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Would you build this DIY project?

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Anonymous
November 12, 2004 11:48:21 PM

Archived from groups: rec.audio.pro (More info?)

Hi folks:

Let me launch a trial balloon here. Is this a DIY project that appeals to
you?

It's a microphone preamp, solid state, transformer in (Jensen),
transformerless balanced +4dBu out with a separate -10dBV unbalanced out. IC
based, up to 8 channels in a 2U case, plus separate power pack. Phantom on
all channels, 100Hz rolloff selectable on all channels, otherwise no EQ.
Designed to be comparable to the Sytek in price, performance and feature
set, but with transformer-coupled inputs. All parts obtainable (to North
Americans, at any rate) from Digi-Key and Allied Electronics, except for the
transformers, which come directly from Jensen. On-card regulation. Like the
Sytek, there are some optional choices in what ICs you use.

Approximate costs are as follows. These include everything except the cases,
which are up to you. At the moment I'm assuming the PC boards would cost
$25.00 / ea.; that's the biggest unknown in the equation. I can't really
fill that in until I design the boards, and I'm not gonna do that until I
find out whether anybody's interested. (Also, of course, price of the boards
will vary depending on how many I order.) There are options which will raise
the price, and some that will lower it, but this is the basic design.

Each input channel: $220.00

Power Supply: $120.00

So a 4-channel unit would cost almost exactly $1k, not counting boxes. An
8-channel would be $1880, ditto. I'd make my slice selling the PC boards and
writing it up for the magazines.

Any interest?

Peace,
Paul

More about : build diy project

Anonymous
November 12, 2004 11:48:22 PM

Archived from groups: rec.audio.pro (More info?)

"Paul Stamler" wrote ...
> Let me launch a trial balloon here. Is this a DIY project that
> appeals to you?

Yes, it would appeal to me as a DIY project.
I'd appreciate a bit more detail on the $220/channel costing.
Anonymous
November 12, 2004 11:48:22 PM

Archived from groups: rec.audio.pro (More info?)

In article <pk9ld.891630$Gx4.439542@bgtnsc04-news.ops.worldnet.att.net> pstamlerhell@pobox.com writes:

> Let me launch a trial balloon here. Is this a DIY project that appeals to
> you?
>
> It's a microphone preamp, solid state, transformer in (Jensen),
> transformerless balanced +4dBu out with a separate -10dBV unbalanced out. IC
> based, up to 8 channels in a 2U case, plus separate power pack. Phantom on
> all channels, 100Hz rolloff selectable on all channels, otherwise no EQ.
> Designed to be comparable to the Sytek in price, performance and feature
> set, but with transformer-coupled inputs.

> So a 4-channel unit would cost almost exactly $1k, not counting boxes. An
> 8-channel would be $1880, ditto. I'd make my slice selling the PC boards and
> writing it up for the magazines.

I think that the average DIYer today would find that to be too much
cash to put into a project, particularly since it involves a case and
considerable metalworking skill to make a unit that looks decent. You
might sell about ten, and you know what Recording pays for articles.
<g>




--
I'm really Mike Rivers (mrivers@d-and-d.com)
However, until the spam goes away or Hell freezes over,
lots of IP addresses are blocked from this system. If
you e-mail me and it bounces, use your secret decoder ring
and reach me here: double-m-eleven-double-zero at yahoo
Related resources
Anonymous
November 12, 2004 11:48:22 PM

Archived from groups: rec.audio.pro (More info?)

How much to build the powersupply? I assume we'd be building it. I'd be
interested. I love reading the DIY also. Still want to piece together a
few of Scott Dorsey's passive EQ's. I hope it'd sound pretty awesome
220 per channel is a bit of cash. I won't say steep but it is a DIY
project for almost 2 grand. (If you do 8 channels)

mark me down for interest peaked.

On 2004-11-12 12:48:21 -0800, "Paul Stamler" <pstamlerhell@pobox.com> said:

> Hi folks:
>
> Let me launch a trial balloon here. Is this a DIY project that appeals to
> you?
>
> It's a microphone preamp, solid state, transformer in (Jensen),
> transformerless balanced +4dBu out with a separate -10dBV unbalanced out. IC
> based, up to 8 channels in a 2U case, plus separate power pack. Phantom on
> all channels, 100Hz rolloff selectable on all channels, otherwise no EQ.
> Designed to be comparable to the Sytek in price, performance and feature
> set, but with transformer-coupled inputs. All parts obtainable (to North
> Americans, at any rate) from Digi-Key and Allied Electronics, except for the
> transformers, which come directly from Jensen. On-card regulation. Like the
> Sytek, there are some optional choices in what ICs you use.
>
> Approximate costs are as follows. These include everything except the cases,
> which are up to you. At the moment I'm assuming the PC boards would cost
> $25.00 / ea.; that's the biggest unknown in the equation. I can't really
> fill that in until I design the boards, and I'm not gonna do that until I
> find out whether anybody's interested. (Also, of course, price of the boards
> will vary depending on how many I order.) There are options which will raise
> the price, and some that will lower it, but this is the basic design.
>
> Each input channel: $220.00
>
> Power Supply: $120.00
>
> So a 4-channel unit would cost almost exactly $1k, not counting boxes. An
> 8-channel would be $1880, ditto. I'd make my slice selling the PC boards and
> writing it up for the magazines.
>
> Any interest?
>
> Peace,
> Paul
Anonymous
November 12, 2004 11:48:23 PM

Archived from groups: rec.audio.pro (More info?)

You could probably find a suitable Bud box for it. I do agree the
pricing is something to consider still.

cheers

garrett


On 2004-11-12 17:37:14 -0800, mrivers@d-and-d.com (Mike Rivers) said:
> I think that the average DIYer today would find that to be too much
> cash to put into a project, particularly since it involves a case and
> considerable metalworking skill to make a unit that looks decent. You
> might sell about ten, and you know what Recording pays for articles.
> <g>
Anonymous
November 13, 2004 1:19:11 AM

Archived from groups: rec.audio.pro (More info?)

In article <znr1100301967k@trad>, Mike Rivers <mrivers@d-and-d.com> wrote:
>
>I think that the average DIYer today would find that to be too much
>cash to put into a project, particularly since it involves a case and
>considerable metalworking skill to make a unit that looks decent. You
>might sell about ten, and you know what Recording pays for articles.
><g>

Skip the input transformer. Go transformerless with the THAT large area
transistors, and save fifty bucks a channel that way.

Get prepunched cases available from SESCOM or one of the other custom
cabinet guys. That's the real rub on these things and it's also a substantial
part of the total cost.
--scott
--
"C'est un Nagra. C'est suisse, et tres, tres precis."
November 13, 2004 1:53:41 AM

Archived from groups: rec.audio.pro (More info?)

Mike Rivers wrote:

> I think that the average DIYer today would find that to be too much
> cash to put into a project, particularly since it involves a case and
> considerable metalworking skill to make a unit that looks decent.

Very true. With the RNP going for $475 new, what's the point (unless you
just absolutely HAVE to have transformers). And why would you reall NEED
transformers at that price point, since Shure 57s behave themselves pretty
well with the RNP?
Anonymous
November 13, 2004 5:27:27 AM

Archived from groups: rec.audio.pro (More info?)

You might try bouncing this around at the 'lab' forum at prodigy. There
is a lot of pro audio DIY stuff going on there.

http://www.prodigy-pro.com/forum/index.php

Brian



Paul Stamler wrote:
> Hi folks:
>
> Let me launch a trial balloon here. Is this a DIY project that appeals to
> you?
>
> It's a microphone preamp, solid state, transformer in (Jensen),
> transformerless balanced +4dBu out with a separate -10dBV unbalanced out. IC
> based, up to 8 channels in a 2U case, plus separate power pack. Phantom on
> all channels, 100Hz rolloff selectable on all channels, otherwise no EQ.
> Designed to be comparable to the Sytek in price, performance and feature
> set, but with transformer-coupled inputs. All parts obtainable (to North
> Americans, at any rate) from Digi-Key and Allied Electronics, except for the
> transformers, which come directly from Jensen. On-card regulation. Like the
> Sytek, there are some optional choices in what ICs you use.
>
> Approximate costs are as follows. These include everything except the cases,
> which are up to you. At the moment I'm assuming the PC boards would cost
> $25.00 / ea.; that's the biggest unknown in the equation. I can't really
> fill that in until I design the boards, and I'm not gonna do that until I
> find out whether anybody's interested. (Also, of course, price of the boards
> will vary depending on how many I order.) There are options which will raise
> the price, and some that will lower it, but this is the basic design.
>
> Each input channel: $220.00
>
> Power Supply: $120.00
>
> So a 4-channel unit would cost almost exactly $1k, not counting boxes. An
> 8-channel would be $1880, ditto. I'd make my slice selling the PC boards and
> writing it up for the magazines.
>
> Any interest?
>
> Peace,
> Paul
>
>
Anonymous
November 13, 2004 10:25:53 AM

Archived from groups: rec.audio.pro (More info?)

"Richard Crowley" <rcrowley7@xprt.net> wrote in message
news:10papfq9fbrr228@corp.supernews.com...
> "Paul Stamler" wrote ...
> > Let me launch a trial balloon here. Is this a DIY project that
> > appeals to you?
>
> Yes, it would appeal to me as a DIY project.
> I'd appreciate a bit more detail on the $220/channel costing.

Uh, whoops -- I added something in twice. The cost would be closer to
$175/channel. The design is a slimmed-down version of the "project-r" preamp
I published in Recording several years ago. So 4 channels would cost $700,
plus $140 for the power supply (that just went up -- sorry, this is still
not quite a finished design) and whatever you wanted to spend for the boxes.
$840 total; $1540 for 8 channels.

The $175/channel breaks down this way (all figures rounded to nearest US$):

Circuit board - $25 (that part's guesswork).

Transformer - $67.

Stage 1 - $33-36, depending on choice of chip. The bulk of that cost is the
XLR, level control, and switches for the bass rolloff and the phantom
on/off.

Stage 2 - $15.

Balanced output - $16.

On-card regulators - $18.

About the raw supply for $120: I freely admit it's over-designed. In the
previous design I had a fairly normal power supply (with tons of
capacitance) and a very fancy, two-stage regulator (317/337 pre-regulators
in the box, plus Sulzer-type op-amp+pass-transistor regulators on the cards.
That was fun, but it led some builders to problems; the same circuits that
stayed perfectly stable for me, oscillated like crazy for them. Turns out I
was using an older version of the 5534 chip in the regulators (Signetics),
which is no longer available. The new ones are less stable in that circuit.
Most of the folks who built the preamp ended up using TL071s in the
regulators. But I digress.

The new raw supply is one which pays somewhat fanatical attention to
RFI-proofing, including filtering out the crud that comes from the diodes'
switching off, and it incorporates some interesting things I learned about
capacitors while researching an article which audioXpress will, I hope,
manage to get into print soon. You probably could save several dollars on it
if you have a good source of surplus 48VCT transformers handy. Or surplus
5-pin XLRs, chassis and cable mount, for the umbilicus.

There are other ways of spending less on this design, notably by omitting
the bass rolloff and/or phantom switches. There are a few ways of spending
more, too, and getting higher performance, including fancier opamps in Stage
2 and substituting an LT1085 regulator for the LM317 on each card.

Anyway, that's the bottom line, or family of them: About $175 for each
channel, assuming my PC board number is right, about $140 for the power
supply. Add boxes.

As to Scott's suggestion of going transformerless: Why? For about the same
amount of money I can get 4 or 8 channels of Sytek, which is excellent. The
point of this design is to give a similar level of performance for those of
us who want to use transformer-coupled inputs, for reasons of RFI-proofness,
loading, whatever.


Peace,
Paul
Anonymous
November 13, 2004 10:35:12 AM

Archived from groups: rec.audio.pro (More info?)

"agent86" <maxwellsmart@control.gov> wrote in message
news:1aeld.10637$WC6.2348@bignews3.bellsouth.net...
> Mike Rivers wrote:
>
> > I think that the average DIYer today would find that to be too much
> > cash to put into a project, particularly since it involves a case and
> > considerable metalworking skill to make a unit that looks decent.
>
> Very true. With the RNP going for $475 new, what's the point (unless you
> just absolutely HAVE to have transformers). And why would you reall NEED
> transformers at that price point, since Shure 57s behave themselves pretty
> well with the RNP?

Revised cost estimate:

2 ch.: $490
4 ch.: $840
8 ch.: $1540

The idea is to provide up to 8 channels of preamp in a 2U box (plus the
outboard power supply). 8 in a box for compactness, particularly for people
doing remote work, or for folks who just want 8 identical good-quality
preamps. It seems to be a pretty popular format at several price points; the
one thing I notice, though, is that none of the 8-bangers out there are
transformer-coupled, and some of us like transformers, for (as I mentioned)
RFI-proofing, loading, whatever. So I'm looking to see whether there's a
niche here. There wouldn't be, I don't think, for a manufactured version of
this; the price would be prohibitive. But perhaps as a DIY it might slip in.
So I'm running it up the flagpole.

Peace,
Paul
Anonymous
November 13, 2004 11:16:40 AM

Archived from groups: rec.audio.pro (More info?)

"Paul Stamler" <pstamlerhell@pobox.com> wrote in message news:<pk9ld.891630$Gx4.439542@bgtnsc04-news.ops.worldnet.att.net>...
> Hi folks:
>
> Let me launch a trial balloon here. Is this a DIY project that appeals to
> you?

(snip)

Hi.

I have some general opinions on magazine-published DIY projects, and
this is aimed not only at Mr Stamler but also Mr Dorsey and everyone
else that do these things.

First, I want to be able to get ALL parts at once from one place, and
that must include the chassis. In case you didn't know this, most
people don't have the tools to drill in metal when it comes to the
diameters needed for XLR connectors.
I want to whip out my credit card, order one neat package with
EVERYTHING in it and sit down a couple of hours every sunday to
assemble. I don't have the time or inclination to order parts from 4
different sources, hunt for a suitable chassi, deal with back-orders
and replacements, pay $30 in shipping for 3 resistors etc.
I know you guys don't want to turn your kitchen into a stocking room
for Digi-key parts, but I'm telling you - when I read "You have to
order this and that from here and there plus machine your own case" I
simply flip the page. And I'm not alone.


Second, I don't think anyone is interested in merly "decent" or
"servicable" projects. I think most readers have too much of that
already. We want "really good" or even "outstanding".
To keep price down I think you need to make costly features optional.
Many people couldn't care less about HP-filtering, phase switches,
metering and balanced outputs in a preamp for instance.

Here are some DIY-projects that I would like to see (and if they have
already been published, please tell me which issue they are in):

-Parametric EQ for live use. A clean parametric EQ with very narrow
bands for full-program corrective live use.

-A/D and D/A converter. There is a remarkable black hole in the market
for stand-alone 2ch converters in the sub $1000 area. I'm sure there
are economical reasons for this but if a DIY project could fit in
there it would be wonderful.

-A "Re-amping" capable DI box. In fact, it wouldn't have to be able to
do normal DI at all.

/Magnus
Anonymous
November 13, 2004 2:11:13 PM

Archived from groups: rec.audio.pro (More info?)

In article <2004111217543375249%@news.speakeasy.net> Garrett Cox writes:

> You could probably find a suitable Bud box for it. I do agree the
> pricing is something to consider still.

If you're going to build something that costs $2,000 or more, you want
to put it in a box that makes it look like $2,000, with all the round
holes round, and lined up straight. And you probably want engraved or
silkscreened legends rather than strips of label tape. One of the
things about undertaking a DIY project (and our furniture-building
friends will surely agree) is not just to make something cheap or to
make something that you can't buy easily, but to make something that
you're proud of - whether it's a mic preamp, a custom cable, or a set
of shelves to store your backups.

There are a couple of companies that advertise in the trade magazines
that custom-punched engraved panels but that's still pretty expensive.
Markertek is one. Hammond makes a nice rack-mount case for
construction projects. A 2-space one runs between $55 and $90
depending on depth and venting.

Power supplies are probably best bought given the difficulty with
finding suitable transformers. That would be in the $100-150 range for
bi-polar 15 to 24 volts plus a single 48 volt supply. You'd need a
chassis or case for those, too.


--
I'm really Mike Rivers (mrivers@d-and-d.com)
However, until the spam goes away or Hell freezes over,
lots of IP addresses are blocked from this system. If
you e-mail me and it bounces, use your secret decoder ring
and reach me here: double-m-eleven-double-zero at yahoo
Anonymous
November 13, 2004 2:17:46 PM

Archived from groups: rec.audio.pro (More info?)

In article <d087955e.0411130816.249b589@posting.google.com>,
magnus_jansen@yahoo.com (Magnus Jans?n) wrote:

> "Paul Stamler" <pstamlerhell@pobox.com> wrote in message
news:<pk9ld.891630$Gx4.439542@bgtnsc04-news.ops.worldnet.att.net>...
> > Hi folks:
> >
> > Let me launch a trial balloon here. Is this a DIY project that appeals to
> > you?
>
> (snip)

[snip]
> Second, I don't think anyone is interested in merly "decent" or
> "servicable" projects. I think most readers have too much of that
> already. We want "really good" or even "outstanding".

This comment hits at the key (potential) problem I see with this project.
Conceptually, it seems similar to the Seventh Circle and Hamptone kits.
The difference seems to be that you are suggesting "comparable to Sytek"
performance. I haven't used the Sytek, but most commenters here suggest
it's "mid-range" in quality. The Seventh Circle preamps aim for "Neve" and
"API" quality, which is clearly a step up. Those guys also offer complete
kits with all the parts, including chassis.

These comments are not meant to dog your idea, just pointing out what's
available and (somewhat) comparable to your idea. It seems to me that,
while the other guys do have a higher cost per channel, they are offering
complete kits and (alleged) higher quality. For myself, given the only
moderate cost differences between your suggested kit and the others, I
would probably buy the Hamptone or Seventh Circle kits; if I'm going to
take the time to build it, I want something as good as (or
better/different) than what I have now (API).

Hamptone and 7C also seem to offer pretty good tech support; are you
looking to do this as an ongoing business where the sales volume is strong
enough to provide comparable support? If not, the other alternative might
be to offer a "PC board only" kit, or a kit with the board and a few
critical parts.

--
Jedd Haas - Artist
http://www.gallerytungsten.com
http://www.epsno.com
Anonymous
November 13, 2004 3:58:12 PM

Archived from groups: rec.audio.pro (More info?)

Magnus Jans?n <magnus_jansen@yahoo.com> wrote:
>
>-Parametric EQ for live use. A clean parametric EQ with very narrow
>bands for full-program corrective live use.

I can't do this as cheaply as you can buy them right now. I am seeing
Orbans selling for next to nothing on the used market. Nobody seems to
want used parametrics.

>-A/D and D/A converter. There is a remarkable black hole in the market
>for stand-alone 2ch converters in the sub $1000 area. I'm sure there
>are economical reasons for this but if a DIY project could fit in
>there it would be wonderful.

For a D/A, there is Sheldon Stokes' project at www.quadesl.com. I built
one and it sounds great. Tell him you want him to do an A/D as well. I
keep bugging him about that and it's not high on his list.

>-A "Re-amping" capable DI box. In fact, it wouldn't have to be able to
>do normal DI at all.

Hell, that is an easy article that will take an afternoon to whip out.
It's a Tamura transformer and a couple resistors.
--scott

--
"C'est un Nagra. C'est suisse, et tres, tres precis."
November 13, 2004 4:44:33 PM

Archived from groups: rec.audio.pro (More info?)

Personally, I wouldn't mind what it looked like as long as it sounded
good and the 1500 or 1800 I spent was justified. I think the purpose
for me would be just usability. No bling or whatever.

cheers

garrett


On 2004-11-13 08:11:13 -0800, mrivers@d-and-d.com (Mike Rivers) said:
>>
>
> If you're going to build something that costs $2,000 or more, you want
> to put it in a box that makes it look like $2,000, with all the round
> holes round, and lined up straight. And you probably want engraved or
> silkscreened legends rather than strips of label tape. One of the
> things about undertaking a DIY project (and our furniture-building
> friends will surely agree) is not just to make something cheap or to
> make something that you can't buy easily, but to make something that
> you're proud of - whether it's a mic preamp, a custom cable, or a set
> of shelves to store your backups.
>
> There are a couple of companies that advertise in the trade magazines
> that custom-punched engraved panels but that's still pretty expensive.
> Markertek is one. Hammond makes a nice rack-mount case for
> construction projects. A 2-space one runs between $55 and $90
> depending on depth and venting.
>
> Power supplies are probably best bought given the difficulty with
> finding suitable transformers. That would be in the $100-150 range for
> bi-polar 15 to 24 volts plus a single 48 volt supply. You'd need a
> chassis or case for those, too.
November 13, 2004 5:26:05 PM

Archived from groups: rec.audio.pro (More info?)

....

and I'd make sure the design was RFI proof for the input and output as
well as the power supply.

I think RFI suseptability is one of the biggest weakness of commercial
gear.

If you create a bullet proof design RFI wse, it would have appeal.

That means ground the XLR connector shield pin and shell DIRECTLY to
the metal chassis for starters.


Mark
November 13, 2004 6:30:31 PM

Archived from groups: rec.audio.pro (More info?)

Paul Stamler wrote:

> Revised cost estimate:
>
> 2 ch.: $490
> 4 ch.: $840
> 8 ch.: $1540
>
> The idea is to provide up to 8 channels of preamp in a 2U box (plus the
> outboard power supply). 8 in a box for compactness, particularly for
> people doing remote work, or for folks who just want 8 identical
> good-quality preamps. It seems to be a pretty popular format at several
> price points; the one thing I notice, though, is that none of the
> 8-bangers out there are transformer-coupled, and some of us like
> transformers, for (as I mentioned) RFI-proofing, loading, whatever. So I'm
> looking to see whether there's a niche here. There wouldn't be, I don't
> think, for a manufactured version of this; the price would be prohibitive.
> But perhaps as a DIY it might slip in. So I'm running it up the flagpole.

What's street on the 8 channel Presonus these days? The Full Compass
catalog copy says "Jensen", but IIRC, they had switched to a cheaper
transformer sometime back.

I'm one of those who likes transformers too. But I've come to the
conclusion that the most cost effective avenue (for me) is to save up for a
GR or a Hardy (since I am determined to get one eventually anyway).
Obviously, everybody's situation is different. But I kind of think most
people would sooner buy a complete functional unit than build it IF what
they need is available at anywhere close to the same cost.

But good luck with it anyway.
Anonymous
November 13, 2004 6:30:32 PM

Archived from groups: rec.audio.pro (More info?)

"agent86" <maxwellsmart@control.gov> wrote in message
news:o Lsld.21427$z3.19754@bignews5.bellsouth.net...
>
> What's street on the 8 channel Presonus these days? The Full Compass
> catalog copy says "Jensen", but IIRC, they had switched to a cheaper
> transformer sometime back.

I assume you mean the M80, since the other Presonus 8-channel units don't
have transformers. The M80 can be had new for around $1400.

Hal Laurent
Baltimore
Anonymous
November 13, 2004 9:00:45 PM

Archived from groups: rec.audio.pro (More info?)

"Paul Stamler" <pstamlerhell@pobox.com> wrote in message
news:p k9ld.891630$Gx4.439542@bgtnsc04-news.ops.worldnet.att.net...
> Hi folks:
>
> Let me launch a trial balloon here. Is this a DIY project that
appeals to
> you?
>
> It's a microphone preamp, solid state, transformer in (Jensen),
> transformerless balanced +4dBu out with a separate -10dBV unbalanced
out. IC
> based, up to 8 channels in a 2U case, plus separate power pack.
Phantom on
> all channels, 100Hz rolloff selectable on all channels, otherwise no
EQ.
> Designed to be comparable to the Sytek in price, performance and
feature
> set, but with transformer-coupled inputs. All parts obtainable (to
North
> Americans, at any rate) from Digi-Key and Allied Electronics, except
for the
> transformers, which come directly from Jensen. On-card regulation.
Like the
> Sytek, there are some optional choices in what ICs you use.
>
> Approximate costs are as follows. These include everything except
the cases,
> which are up to you. At the moment I'm assuming the PC boards would
cost
> $25.00 / ea.; that's the biggest unknown in the equation. I can't
really
> fill that in until I design the boards, and I'm not gonna do that
until I
> find out whether anybody's interested. (Also, of course, price of
the boards
> will vary depending on how many I order.) There are options which
will raise
> the price, and some that will lower it, but this is the basic
design.
>
> Each input channel: $220.00
>
> Power Supply: $120.00
>
> So a 4-channel unit would cost almost exactly $1k, not counting
boxes. An
> 8-channel would be $1880, ditto. I'd make my slice selling the PC
boards and
> writing it up for the magazines.

None whatsoever. There are already too many high-priced mike preamps
on the market (from the point of view of manufacturers.) If you want
to design something useful, come up with a battery operated unit at
$50/channel.

Norm Strong
Anonymous
November 13, 2004 9:00:46 PM

Archived from groups: rec.audio.pro (More info?)

normanstrong wrote:

> If you want
> to design something useful, come up with a battery operated unit at
> $50/channel.

My sentiment as well. No rolloff necessasary, 60 dB gain,
-130 dBu A weighted Ein noise, phantom power.

What I'm dying for is a four channel as per above but with a
form of gain control that will allow any number of channels
to be ganged and operated with a single control. Some kind
precision voltage controled pot on each channel if such a
thing exists.


Bob
--

"Things should be described as simply as possible, but no
simpler."

A. Einstein
Anonymous
November 13, 2004 9:04:05 PM

Archived from groups: rec.audio.pro (More info?)

<Garrett Cox> wrote in message
news:2004111217503816807%@news.speakeasy.net...
> How much to build the powersupply? I assume we'd be building it. I'd
be
> interested. I love reading the DIY also. Still want to piece
together a
> few of Scott Dorsey's passive EQ's. I hope it'd sound pretty awesome
> 220 per channel is a bit of cash. I won't say steep but it is a DIY
> project for almost 2 grand. (If you do 8 channels)
>
> mark me down for interest peaked.
>
> On 2004-11-12 12:48:21 -0800, "Paul Stamler"
<pstamlerhell@pobox.com> said:
>
> > Hi folks:
> >
> > Let me launch a trial balloon here. Is this a DIY project that
appeals to
> > you?
> >
> > It's a microphone preamp, solid state, transformer in (Jensen),
> > transformerless balanced +4dBu out with a separate -10dBV
unbalanced out. IC
> > based, up to 8 channels in a 2U case, plus separate power pack.
Phantom on
> > all channels, 100Hz rolloff selectable on all channels, otherwise
no EQ.
> > Designed to be comparable to the Sytek in price, performance and
feature
> > set, but with transformer-coupled inputs. All parts obtainable (to
North
> > Americans, at any rate) from Digi-Key and Allied Electronics,
except for the
> > transformers, which come directly from Jensen. On-card regulation.
Like the
> > Sytek, there are some optional choices in what ICs you use.
> >
> > Approximate costs are as follows. These include everything except
the cases,
> > which are up to you. At the moment I'm assuming the PC boards
would cost
> > $25.00 / ea.; that's the biggest unknown in the equation. I can't
really
> > fill that in until I design the boards, and I'm not gonna do that
until I
> > find out whether anybody's interested. (Also, of course, price of
the boards
> > will vary depending on how many I order.) There are options which
will raise
> > the price, and some that will lower it, but this is the basic
design.
> >
> > Each input channel: $220.00
> >
> > Power Supply: $120.00
> >
> > So a 4-channel unit would cost almost exactly $1k, not counting
boxes. An
> > 8-channel would be $1880, ditto. I'd make my slice selling the PC
boards and
> > writing it up for the magazines.
> >
> > Any interest?
> >
> > Peace,
> > Paul
>
>
Anonymous
November 13, 2004 9:04:50 PM

Archived from groups: rec.audio.pro (More info?)

<Garrett Cox> wrote in message
news:2004111217503816807%@news.speakeasy.net...
> How much to build the powersupply? I assume we'd be building it. I'd
be
> interested. I love reading the DIY also. Still want to piece
together a
> few of Scott Dorsey's passive EQ's. I hope it'd sound pretty awesome
> 220 per channel is a bit of cash. I won't say steep but it is a DIY
> project for almost 2 grand. (If you do 8 channels)
>
> mark me down for interest peaked.

I think the word you're looking for there is 'piqued'.
Anonymous
November 13, 2004 9:41:02 PM

Archived from groups: rec.audio.pro (More info?)

"Mike Rivers" <mrivers@d-and-d.com> wrote in message
news:znr1100355094k@trad...

> There are a couple of companies that advertise in the trade magazines
> that custom-punched engraved panels but that's still pretty expensive.
> Markertek is one. Hammond makes a nice rack-mount case for
> construction projects. A 2-space one runs between $55 and $90
> depending on depth and venting.

Sescom sells some for about $35. They offer a custom punching service too.

> Power supplies are probably best bought given the difficulty with
> finding suitable transformers. That would be in the $100-150 range for
> bi-polar 15 to 24 volts plus a single 48 volt supply. You'd need a
> chassis or case for those, too.

Not really necessary; in this design I used 48VCT transformers from Allied
Electronics. They carry several brands, including their house brand,
Stancor, Hammond & Parallax. Decent transformers were very hard to find a
few years ago, but they've gotten easier recently. And the commercial
supplies don't take the extra pains to suppress RFI.

Peace,
Paul
Anonymous
November 13, 2004 9:48:57 PM

Archived from groups: rec.audio.pro (More info?)

"Magnus Jans?n" <magnus_jansen@yahoo.com> wrote in message
news:D 087955e.0411130816.249b589@posting.google.com...

> First, I want to be able to get ALL parts at once from one place, and
> that must include the chassis. In case you didn't know this, most
> people don't have the tools to drill in metal when it comes to the
> diameters needed for XLR connectors.
> I want to whip out my credit card, order one neat package with
> EVERYTHING in it and sit down a couple of hours every sunday to
> assemble. I don't have the time or inclination to order parts from 4
> different sources, hunt for a suitable chassi, deal with back-orders
> and replacements, pay $30 in shipping for 3 resistors etc.
> I know you guys don't want to turn your kitchen into a stocking room
> for Digi-key parts, but I'm telling you - when I read "You have to
> order this and that from here and there plus machine your own case" I
> simply flip the page. And I'm not alone.

You sure aren't. I'd love to be able to spec something exactly that way. So
far, though, I haven't found *any* dealer that has everything. If I could, I
would specify them that way in a microsecond.

> Second, I don't think anyone is interested in merly "decent" or
> "servicable" projects. I think most readers have too much of that
> already. We want "really good" or even "outstanding".
> To keep price down I think you need to make costly features optional.
> Many people couldn't care less about HP-filtering, phase switches,
> metering and balanced outputs in a preamp for instance.

Very good point. In this design, you can leave out whatever you don't want;
leaving out the high-pass filter will save $5-something per channel (the
price of the switch), leaving out the balanced outputs will save about $16
per channel. By leaving the phantom on all the time (global on/off switching
only), you save another $5-something. So a stripped-down version would cost
about $148 a channel.

> Here are some DIY-projects that I would like to see (and if they have
> already been published, please tell me which issue they are in):
>
> -Parametric EQ for live use. A clean parametric EQ with very narrow
> bands for full-program corrective live use.
>
> -A/D and D/A converter. There is a remarkable black hole in the market
> for stand-alone 2ch converters in the sub $1000 area. I'm sure there
> are economical reasons for this but if a DIY project could fit in
> there it would be wonderful.
>
> -A "Re-amping" capable DI box. In fact, it wouldn't have to be able to
> do normal DI at all.

One I'd like to see, and don't have the requisite knowledge to design, would
be a really good word clock generator for a couple of hundred bucks. Scott,
are you lisening?

Peace,
Paul
Anonymous
November 13, 2004 9:48:58 PM

Archived from groups: rec.audio.pro (More info?)

On 13 Nov 2004 17:06:49 -0500, kludge@panix.com (Scott Dorsey) wrote:

>
>The long-awaited tube mike preamp article that I promised Nick Batzdorf
>back when he was editing Recording has still not come out yet, and finding
>a single parts source is half of the problem there. I have it down to six
>suppliers but that's way too many.

Would that be the transformerless input :-)


Frank /~ http://newmex.com/f10
@/
Anonymous
November 13, 2004 9:58:49 PM

Archived from groups: rec.audio.pro (More info?)

"Jedd Haas" <jnh@epsno.com> wrote in message
news:jnh-1311041117460001@192.168.0.101...

> > Second, I don't think anyone is interested in merly "decent" or
> > "servicable" projects. I think most readers have too much of that
> > already. We want "really good" or even "outstanding".
>
> This comment hits at the key (potential) problem I see with this project.
> Conceptually, it seems similar to the Seventh Circle and Hamptone kits.
> The difference seems to be that you are suggesting "comparable to Sytek"
> performance. I haven't used the Sytek, but most commenters here suggest
> it's "mid-range" in quality. The Seventh Circle preamps aim for "Neve" and
> "API" quality, which is clearly a step up. Those guys also offer complete
> kits with all the parts, including chassis.
>
> These comments are not meant to dog your idea, just pointing out what's
> available and (somewhat) comparable to your idea. It seems to me that,
> while the other guys do have a higher cost per channel, they are offering
> complete kits and (alleged) higher quality. For myself, given the only
> moderate cost differences between your suggested kit and the others, I
> would probably buy the Hamptone or Seventh Circle kits; if I'm going to
> take the time to build it, I want something as good as (or
> better/different) than what I have now (API).

The Hamptone is in a different category; it's a "color" preamp rather than
an attempt at a neutral preamp. This, like the Sytek, aims for neutral. I
haven't checked out the Seventh Circle units.

This project doesn't aim at the stars. If you want the stars in a neutral
sort of way, I say buy a rack full of Great River preamps. They're
superb-sounding, and you get a warranty from a well-established company.
This project has a different ambition; I'd put the quality one notch below
Great River (which is still damned good -- I've made some very nice
recordings using this circuit). The tradeoff is convenience (2RU for 8
channels rather than 8) and cost. Like I say, it's a niche.

> Hamptone and 7C also seem to offer pretty good tech support; are you
> looking to do this as an ongoing business where the sales volume is strong
> enough to provide comparable support? If not, the other alternative might
> be to offer a "PC board only" kit, or a kit with the board and a few
> critical parts.

One of the latter options. I'd sell, I think, PC boards and matched
resistors for the phantom power. And I'd provide lots of hand-holding to
anyone with problems; I just spent several months online debugging one of
the older designs with a guy who built it and had problems. Eventually I had
him ship it to me, and it spent a lot of time on my bench. (That was how I
found out the newer batches of 5534s aren't as stable in regulators.) I'd do
that for anyone who bought a PC board from me, for sure.

Peace,
Paul
Anonymous
November 13, 2004 9:58:50 PM

Archived from groups: rec.audio.pro (More info?)

"Paul Stamler" <pstamlerhell@pobox.com> wrote in message
news:JPsld.15735$7i4.1249@bgtnsc05-news.ops.worldnet.att.net...

> This project doesn't aim at the stars. If you want the stars in a neutral
> sort of way, I say buy a rack full of Great River preamps. They're
> superb-sounding, and you get a warranty from a well-established company.
> This project has a different ambition; I'd put the quality one notch below
> Great River (which is still damned good -- I've made some very nice
> recordings using this circuit). The tradeoff is convenience (2RU for 8
> channels rather than 8) and cost. Like I say, it's a niche.

You don't need 8RU for 8 channels of Great River (or Hardy). A pair
of the four-channel versions of either will fit in 2RU. As will 8 channels
of Sytek.

Hal Laurent
Baltimore
Anonymous
November 13, 2004 10:03:38 PM

Archived from groups: rec.audio.pro (More info?)

<Garrett> wrote:

> You could probably find a suitable Bud box for it. I do agree the
> pricing is something to consider still.

> On 2004-11-12 17:37:14 -0800, mrivers@d-and-d.com (Mike Rivers) said:
> > I think that the average DIYer today would find that to be too much
> > cash to put into a project, particularly since it involves a case and
> > considerable metalworking skill to make a unit that looks decent. You
> > might sell about ten, and you know what Recording pays for articles.
> > <g>

I think people think they want to build a great preamp project that
costs less in total per channel than the price of a jensen input
transformer. <g>

--
ha
Anonymous
November 13, 2004 10:08:58 PM

Archived from groups: rec.audio.pro (More info?)

In article <d087955e.0411130816.249b589@posting.google.com> magnus_jansen@yahoo.com writes:

> I have some general opinions on magazine-published DIY projects, and
> this is aimed not only at Mr Stamler but also Mr Dorsey and everyone
> else that do these things.
>
> First, I want to be able to get ALL parts at once from one place, and
> that must include the chassis.

That's really nice, but unless someone is willing to put together a
complete kit, it really can't be done. Paia used to do this but they
don't seem to be quite so active in that area these days. Understand
that this requires a substantial investment when it comes to
metalwork. They can often use resistors, capacitors and op amp chips
for multiple products but they can't punch a chassis for an 8-channel
mic preamp and use it for a compressor.

> In case you didn't know this, most
> people don't have the tools to drill in metal when it comes to the
> diameters needed for XLR connectors.

Actually that isn't too difficult. If you're going to build a $2,000
preamp, you're probably into building things and you don't have to
start out by buying every tool that you need, because you already have
a decent shop. A good start for audio projects is a set of Greenlee
chassis punches for male and female XLR connectors, about $40 a piece.
I'll admit that this can make a single channel project a bit
expensive, but DIY projects are addictive. If you do one, you'll
probably do several.

But I understand completely where you're coming from. When I was in
high school I worked summers and Saturdays in the tool crib of a
machine shop and I built some lovely ham radio gear because I had
access to brakes and punches for making the chassis. It made a big
difference in projects that I started over having to use a ready-made
chassis that was too big, too small, too deep, or too shallow, and had
to make holes for tube sockets by drilling a bunch of holes around the
circumference of a circle and filing out the scrap. Today I have a
drill press but no brake, so I don't do as much DIY as I used to.

> I want to whip out my credit card, order one neat package with
> EVERYTHING in it and sit down a couple of hours every sunday to
> assemble.

Too bad you're too young to have ever built a Heathkit. But they went
out of business because eventually it wasn't cost effective to put
together and document a kit. You could buy the equivalent a whole lot
cheaper. A technician who used to work with me built a Heathkit color
TV and a Heathkit microwave oven, and had Heathkit oscilloscopes and
signal generators in his home TV service shop. In 1965 you could save
money by building the kit, but today you can buy better commercial
products for a fraction of the cost of the Heathkits, even in 1965
dollars.

> Second, I don't think anyone is interested in merly "decent" or
> "servicable" projects. I think most readers have too much of that
> already. We want "really good" or even "outstanding".

This is why I didn't think Paul's project would be a smashing success.
On the other hand, a project like Scott's Oktava mic modifications
that involve a simple circuit board that he can provide, a handful of
parts, and only small hand tools are pretty popular.

> To keep price down I think you need to make costly features optional.
> Many people couldn't care less about HP-filtering, phase switches,
> metering and balanced outputs in a preamp for instance.

I wrote an article in Recording a while back about developing your own
DIY project (using a monitor switcher as an example) in which I
explained exactly that concept - but the point of my article was that
YOU could make those decisions. It's not difficult to find application
notes for transfomrers and op amps that will get you a decent mic
preamp and you can make it "really good" or even "outstanding" by the
way you apply what's in those application notes. If you want someone
to make those decisions for you, you have to accept his take on what's
good for you.

> Here are some DIY-projects that I would like to see (and if they have
> already been published, please tell me which issue they are in):
>
> -Parametric EQ for live use. A clean parametric EQ with very narrow
> bands for full-program corrective live use.

Paia had a kit for one many years ago, and it's probalby still in
their catalog. I built one and I still use it occasionally.

> -A/D and D/A converter. There is a remarkable black hole in the market
> for stand-alone 2ch converters in the sub $1000 area. I'm sure there
> are economical reasons for this but if a DIY project could fit in
> there it would be wonderful.

This is one of those areas (like mic preamps - see John La Grou's
recent postings on the subject) where "art" comes into play. Again,
there are application notes for perfectly good A/D and D/A chips that
will get you the functions with reasonably good performance. But in
order to make it really great, you need a nice clean power supply, a
low jitter clock source, and good analog circuitry around the chip.
That's about four application notes. If you want someone to combine
those, experiment with optimizing components and circuit board layout,
finding sources for all the parts, and punching a chassis, who's going
to pay for it?

> -A "Re-amping" capable DI box. In fact, it wouldn't have to be able to
> do normal DI at all.

This is a perfectly good example of a project that you could develop
yourself. All you need to do is understand what you need to
accomplish. Package it as pretty or as ugly as you wish.


--
I'm really Mike Rivers (mrivers@d-and-d.com)
However, until the spam goes away or Hell freezes over,
lots of IP addresses are blocked from this system. If
you e-mail me and it bounces, use your secret decoder ring
and reach me here: double-m-eleven-double-zero at yahoo
Anonymous
November 13, 2004 10:08:59 PM

Archived from groups: rec.audio.pro (More info?)

Mike Rivers wrote:
> In article <d087955e.0411130816.249b589@posting.google.com> magnus_jansen@yahoo.com writes:
>
>> In case you didn't know this, most
>> people don't have the tools to drill in metal when it comes to
>> the diameters needed for XLR connectors.
>
>
> Actually that isn't too difficult. If you're going to build a $2,000
> preamp, you're probably into building things and you don't have to
> start out by buying every tool that you need, because you already have
> a decent shop. A good start for audio projects is a set of Greenlee
> chassis punches for male and female XLR connectors, about $40 a piece.

I thought these punches were more like $200-250 each? You are talking about the ones with the slots for the mounting screws, right?
Anonymous
November 13, 2004 11:04:44 PM

Archived from groups: rec.audio.pro (More info?)

Mark <makolber@yahoo.com> wrote:
>
>and I'd make sure the design was RFI proof for the input and output as
>well as the power supply.

With an input transformer, that's easy to do. High CMRR and low-pass
filtering are free in the bargain.

>I think RFI suseptability is one of the biggest weakness of commercial
>gear.

That's because people are willing to put up with bad design. It's not just
that transformers are expensive; just looking at the number of internal
ground loops on some commercial boxes out there is amazing.

>If you create a bullet proof design RFI wse, it would have appeal.
>
>That means ground the XLR connector shield pin and shell DIRECTLY to
>the metal chassis for starters.

Not necessarily. Check out Deane Jensen's recent papers on the "Pin 1
Problem."
--scott

--
"C'est un Nagra. C'est suisse, et tres, tres precis."
Anonymous
November 13, 2004 11:12:45 PM

Archived from groups: rec.audio.pro (More info?)

Frank Vuotto <deepthrob@hotmail.com> wrote:
>On 13 Nov 2004 17:06:49 -0500, kludge@panix.com (Scott Dorsey) wrote:
>
>>The long-awaited tube mike preamp article that I promised Nick Batzdorf
>>back when he was editing Recording has still not come out yet, and finding
>>a single parts source is half of the problem there. I have it down to six
>>suppliers but that's way too many.
>
>Would that be the transformerless input :-)

Not at the price point Recording wants for DIY projects. If I could do a
transformerless one for cheap, that would eliminate one of the six suppliers
(which is Lundahl). I played around a little bit with a transformerless
grounded-grid design with a bunch of paralleled tubes, and it sounded good,
but it required a lot of trimming and selected tubes in order to get it
quiet and with low distortion. Actually winds up costing _more_ than a
transformer input, what with all the more expensive input tubes and the
trimpots.

About half of the cost of the preamp actually is in the power supply, and I
worked very hard to try and bring the power supply parts cost down and try
and do it entirely with Digi-Key parts. I was not able to do so. Everything
I did to cut corners in the supply wound up affecting the sound too much.
--scott

--
"C'est un Nagra. C'est suisse, et tres, tres precis."
Anonymous
November 14, 2004 12:42:01 AM

Archived from groups: rec.audio.pro (More info?)

On 2004-11-13, Mike Rivers <mrivers@d-and-d.com> wrote:

> If you're going to build something that costs $2,000 or more, you want
> to put it in a box that makes it look like $2,000, with all the round
> holes round, and lined up straight. And you probably want engraved or
> silkscreened legends rather than strips of label tape.

A nice front panel is easy! You don't have to have a CNC mill yourself,
and you don't have to struggle with the dremel. Check out Front Panel
Express, or Schaeffer AG. The cost depends on the complexity of your
panel, but it is quite reasonable, and cheap enough to be used on
countless low budget DIY synth projects that I've seen.
Anonymous
November 14, 2004 1:47:43 AM

Archived from groups: rec.audio.pro (More info?)

Mark wrote:

> ...
>
> and I'd make sure the design was RFI proof for the input and output as
> well as the power supply.
>
> I think RFI suseptability is one of the biggest weakness of commercial
> gear.
>
> If you create a bullet proof design RFI wse, it would have appeal.
>
> That means ground the XLR connector shield pin and shell DIRECTLY to
> the metal chassis for starters.

Does anyone *not* do that these days ?

Just asking. Been there done that - had the EMI course ( as part of his
consultancy ) over the years from a wonderful Hungarian ? expert.

He thinks the EMI regs are bonkers ( as in totally over the top ) btw !


Graham
November 14, 2004 4:27:02 AM

Archived from groups: rec.audio.pro (More info?)

Sorry yes "piqued" Had a few drinks and was in a hurry. Piqued.

cheers

garrett

On 2004-11-13 10:04:50 -0800, "normanstrong" <normanstrong@comcast.net> said:

>
> <Garrett Cox> wrote in message
> news:2004111217503816807%@news.speakeasy.net...
>> How much to build the powersupply? I assume we'd be building it. I'd
> be
>> interested. I love reading the DIY also. Still want to piece
> together a
>> few of Scott Dorsey's passive EQ's. I hope it'd sound pretty awesome
>> 220 per channel is a bit of cash. I won't say steep but it is a DIY
>> project for almost 2 grand. (If you do 8 channels)
>>
>> mark me down for interest peaked.
>
> I think the word you're looking for there is 'piqued'.
Anonymous
November 14, 2004 7:35:11 AM

Archived from groups: rec.audio.pro (More info?)

On Fri, 12 Nov 2004 20:48:21 GMT, "Paul Stamler"
<pstamlerhell@pobox.com> wrote:

>Hi folks:
>
>Let me launch a trial balloon here. Is this a DIY project that appeals to
>you?
>
>It's a microphone preamp, solid state, transformer in (Jensen),

>...

> I'd make my slice selling the PC boards and
>writing it up for the magazines.

Speaking of PC boards, would it be all thru-hole, or any surface
mount? You're of course aware that more and more parts are only
available in SMT thesedays, and some people won't want to solder SMT
parts (even though the .050 pitch pins aren't hard). Or does it depend
on IC options? You could make a dual thru-hole/surface mount layout
for the chips that come in both.
FWIW, I probably won't build it, though I may buy the magazine you
publish it in.

>
>Any interest?
>
>Peace,
>Paul
>

-----
http://mindspring.com/~benbradley
Anonymous
November 14, 2004 9:59:08 AM

Archived from groups: rec.audio.pro (More info?)

In article <tGsld.15707$7i4.7724@bgtnsc05-news.ops.worldnet.att.net> pstamlerhell@pobox.com writes:

> In this design, you can leave out whatever you don't want;
> leaving out the high-pass filter will save $5-something per channel (the
> price of the switch), leaving out the balanced outputs will save about $16
> per channel. By leaving the phantom on all the time (global on/off switching
> only), you save another $5-something. So a stripped-down version would cost
> about $148 a channel.

Mr. Marketing here . . .

How about presenting it as a two-channel preamp which, I suspect, is
more in demand than an eight-channel preamp. Make a two-channel board
with pads to mount components for phantom powering, the high-pass
filter, and the additional components for the balanced output. Let the
user decide what extra features he wants to add for more flexibility
rather than what features he wants to leave out to save a few bucks.
The power supply will handle up to eight channels worth of boards, so
the preamp can grow as the users' needs grow.

The chassis, panel, and case will remain a stumbling block for many,
however.

--
I'm really Mike Rivers (mrivers@d-and-d.com)
However, until the spam goes away or Hell freezes over,
lots of IP addresses are blocked from this system. If
you e-mail me and it bounces, use your secret decoder ring
and reach me here: double-m-eleven-double-zero at yahoo
Anonymous
November 14, 2004 9:59:09 AM

Archived from groups: rec.audio.pro (More info?)

In article <slrncpcvuj.ldv.fishbowl@radagast.home.conservatory.com> fishbowl@conservatory.com writes:

> A nice front panel is easy! You don't have to have a CNC mill yourself,
> and you don't have to struggle with the dremel. Check out Front Panel
> Express, or Schaeffer AG. The cost depends on the complexity of your
> panel, but it is quite reasonable, and cheap enough to be used on
> countless low budget DIY synth projects that I've seen.

I've heard of this outfit but have never investigated them. Why not
get an estimate for a project like this and pass it on to us? Don't
forget holes for the gain controls, high pass filter and phantom power
switches, might as well add a polarity switch, power supply connector,
and both inputs and outputs. Would you put the inputs on the front
(for convenience) or on the rear (for convenience <g>). That's two
panels, in case you weren't counting.

Do they make aluminum panels suitable for rack mounting that can
support the weight of eight transformers? (yeah, I know, it makes a
difference whether you mount them near the front or back). You'd
probably want a 3/16" or 1/4" thick front panel if that was also the
rack mount point, or at least an 1/8" panel with add-on rack ears.
Then you'd need a chassis and stand-offs to mount the circuit board.
All in all, a fair number of mechanical parts. This is why companies
that build electronic equipment have mechanical engineers working for
them, at least as consultants.




--
I'm really Mike Rivers (mrivers@d-and-d.com)
However, until the spam goes away or Hell freezes over,
lots of IP addresses are blocked from this system. If
you e-mail me and it bounces, use your secret decoder ring
and reach me here: double-m-eleven-double-zero at yahoo
Anonymous
November 14, 2004 9:59:10 AM

Archived from groups: rec.audio.pro (More info?)

In article <2004111313443316807%coxg@usfcaedu> coxg@usfca.edu writes:

> Personally, I wouldn't mind what it looked like as long as it sounded
> good and the 1500 or 1800 I spent was justified. I think the purpose
> for me would be just usability. No bling or whatever.

That's OK if you're doing it just for yourself and don't have a lot of
pride. But if you have a client coming in and you plug a mic into a
ragged looking box, what's he going to think?

--
I'm really Mike Rivers (mrivers@d-and-d.com)
However, until the spam goes away or Hell freezes over,
lots of IP addresses are blocked from this system. If
you e-mail me and it bounces, use your secret decoder ring
and reach me here: double-m-eleven-double-zero at yahoo
Anonymous
November 14, 2004 11:23:50 AM

Archived from groups: rec.audio.pro (More info?)

"Scott Dorsey" <kludge@panix.com> wrote in message
news:cn6bed$m62$1@panix2.panix.com...

> About half of the cost of the preamp actually is in the power supply, and
I
> worked very hard to try and bring the power supply parts cost down and try
> and do it entirely with Digi-Key parts. I was not able to do so.
Everything
> I did to cut corners in the supply wound up affecting the sound too much.

Scott, try Allied. The new catalog has a surprising number of
tube-compatible power transformers. Combine them with Digi-Key plus a tube
supplier and you may bring the number of suppliers down to three.

Peace,
Paul
Anonymous
November 14, 2004 11:30:52 AM

Archived from groups: rec.audio.pro (More info?)

"Ben Bradley" <ben_nospam_bradley@mindspring.com> wrote in message
news:ulndp0167osb1q60a7krmp41c7gskunq56@4ax.com...

> > I'd make my slice selling the PC boards and
> >writing it up for the magazines.
>
> Speaking of PC boards, would it be all thru-hole, or any surface
> mount? You're of course aware that more and more parts are only
> available in SMT thesedays, and some people won't want to solder SMT
> parts (even though the .050 pitch pins aren't hard). Or does it depend
> on IC options? You could make a dual thru-hole/surface mount layout
> for the chips that come in both.

Through-hole. I'm too shaky to solder SMT myself.

The ICs are nothing exotic, and available in 8-DIPs.

Peace,
Paul
Anonymous
November 14, 2004 12:13:15 PM

Archived from groups: rec.audio.pro (More info?)

Kurt Albershardt <kurt@nv.net> wrote:
>Mike Rivers wrote:
>>
>> Actually that isn't too difficult. If you're going to build a $2,000
>> preamp, you're probably into building things and you don't have to
>> start out by buying every tool that you need, because you already have
>> a decent shop. A good start for audio projects is a set of Greenlee
>> chassis punches for male and female XLR connectors, about $40 a piece.
>
>I thought these punches were more like $200-250 each? You are talking about the ones with the slots for the mounting screws, right?

No, he is talking about round Greenless punches, without holes for mounting
screws. You punch the hole, put in the connector, and then drill the screw
holes.

I did not know that there were ANY hand punches that will do all three holes
in one operation! If you know of one, I would really like to know. I have
used a small hydraulic press with custom tooling, a combination that cost a
lot more than $200 and was not convenient to take into the field. A hand punch
that would do all three holes would be wonderful for field modification work.
--scott

--
"C'est un Nagra. C'est suisse, et tres, tres precis."
Anonymous
November 14, 2004 2:03:16 PM

Archived from groups: rec.audio.pro (More info?)

On 14 Nov 2004 06:59:08 -0500, mrivers@d-and-d.com (Mike Rivers)
wrote:

>The chassis, panel, and case will remain a stumbling block for many,
>however.


Amen, even for the experienced it usually takes twice as long to box
a project as it does to put together a circuit or perf board.


Frank /~ http://newmex.com/f10
@/
Anonymous
November 14, 2004 4:11:26 PM

Archived from groups: rec.audio.pro (More info?)

In article <cn6bed$m62$1@panix2.panix.com> kludge@panix.com writes:

> About half of the cost of the preamp actually is in the power supply, and I
> worked very hard to try and bring the power supply parts cost down and try
> and do it entirely with Digi-Key parts. I was not able to do so. Everything
> I did to cut corners in the supply wound up affecting the sound too much.

The difference between Scott and some commercial manufacturers is that
he has the decency not to offer a product where cutting corners affect
the sound too much.


--
I'm really Mike Rivers (mrivers@d-and-d.com)
However, until the spam goes away or Hell freezes over,
lots of IP addresses are blocked from this system. If
you e-mail me and it bounces, use your secret decoder ring
and reach me here: double-m-eleven-double-zero at yahoo
Anonymous
November 14, 2004 4:11:27 PM

Archived from groups: rec.audio.pro (More info?)

In article <2vnuanF2mp098U1@uni-berlin.de> kurt@nv.net writes:

> > A good start for audio projects is a set of Greenlee
> > chassis punches for male and female XLR connectors, about $40 a piece.
>
> I thought these punches were more like $200-250 each? You are talking about
> the ones with the slots for the mounting screws, right?

No, punches that make 3/4" (male) and 15/16" (female) round holes.
There's a 3/8" bolt that draws the punch through the die, so you have
to be able to drill a 3/8" hole but that's easy enough with a Harry
Homeowner electric hand drill - though getting it in the right place
is a little tricky.

Markertek sells the punches. Look in their catalog under C for
"Chassis Punch" (at least that's how it's listed in the paper catalog
I have here).

Here ya go: http://www.markertek.com/SearchProduct.asp?item=GL730A&...

And on the next page, they have a 2 space rack mount chassis that takes
five of their panel modules front and rear (they come pre-punched for some
things useful like XLR connectors, or blank). The chassis is $65. Panels are
$6 - $10 and come up to triple width.

I took a look at the Sescom web page as Monte suggested and they have a
similar rack mount chassis with what looks like solid front and rear panels
for around $40 that would probably accommodate the preamp. They also
have chassis punches for the microphone connectors that are about half the
price of those from Markertek. Sescom doesn't specify a brand name
(Markertek's are from Greenlee who has been making them for about 50
years) so it's possible that the Sescom ones are Chinese. They're probably
fine for a couple of projects, but may not last through a lifetime of building.




--
I'm really Mike Rivers (mrivers@d-and-d.com)
However, until the spam goes away or Hell freezes over,
lots of IP addresses are blocked from this system. If
you e-mail me and it bounces, use your secret decoder ring
and reach me here: double-m-eleven-double-zero at yahoo
Anonymous
November 14, 2004 6:03:14 PM

Archived from groups: rec.audio.pro (More info?)

In article <cn7p5r$kvo$1@panix2.panix.com> kludge@panix.com writes:

> I did not know that there were ANY hand punches that will do all three holes
> in one operation! If you know of one, I would really like to know.

I think I've seen a DB25 hole punch that also punches the mounting
holes. But it's a prettly clumsy thing, and costs about $100.




--
I'm really Mike Rivers (mrivers@d-and-d.com)
However, until the spam goes away or Hell freezes over,
lots of IP addresses are blocked from this system. If
you e-mail me and it bounces, use your secret decoder ring
and reach me here: double-m-eleven-double-zero at yahoo
Anonymous
November 14, 2004 6:09:40 PM

Archived from groups: rec.audio.pro (More info?)

mrivers@d-and-d.com (Mike Rivers) wrote in message news:<znr1100380037k@trad>...
> In article <d087955e.0411130816.249b589@posting.google.com> magnus_jansen@yahoo.com writes:
>
> > I have some general opinions on magazine-published DIY projects, and
> > this is aimed not only at Mr Stamler but also Mr Dorsey and everyone
> > else that do these things.
> >
> > First, I want to be able to get ALL parts at once from one place, and
> > that must include the chassis.
>
> That's really nice, but unless someone is willing to put together a
> complete kit, it really can't be done. Paia used to do this but they
> don't seem to be quite so active in that area these days. Understand
> that this requires a substantial investment when it comes to
> metalwork. They can often use resistors, capacitors and op amp chips
> for multiple products but they can't punch a chassis for an 8-channel
> mic preamp and use it for a compressor.

Scott Hampton seems to manage just fine. Of course there isn't a
decent business in doing kits, but Mr Dorsey et al arn't making any
money on the kits as it so... As a naive end-user/reader it's hard to
see the difference in not making much money on "hard to get parts for
and then I have to slave away on housing"-kits and not making much
money on "yummy it's just one package to order for off-hours soldering
goodness". Just add the extra labor costs onto the cost of the full
package to take you from "losing money" to "not making much money".

> > Second, I don't think anyone is interested in merly "decent" or
> > "servicable" projects. I think most readers have too much of that
> > already. We want "really good" or even "outstanding".
>
> This is why I didn't think Paul's project would be a smashing success.
> On the other hand, a project like Scott's Oktava mic modifications
> that involve a simple circuit board that he can provide, a handful of
> parts, and only small hand tools are pretty popular.

Yes it's an examplary mod. Unfortunately he does in fact NOT provide
replacement circuit bords as you say, which I kind of whish he did
since he mentions about a million times how easy it is to wreck the
board. I wonder, would there be enough room to make it have a truly
balanced output if one redesigned the board?

> > To keep price down I think you need to make costly features optional.
> > Many people couldn't care less about HP-filtering, phase switches,
> > metering and balanced outputs in a preamp for instance.
>
> I wrote an article in Recording a while back about developing your own
> DIY project (using a monitor switcher as an example) in which I
> explained exactly that concept - but the point of my article was that
> YOU could make those decisions. It's not difficult to find application
> notes for transfomrers and op amps that will get you a decent mic
> preamp and you can make it "really good" or even "outstanding" by the
> way you apply what's in those application notes. If you want someone
> to make those decisions for you, you have to accept his take on what's
> good for you.

The problem is that "DIY" is not a good term for what we are
discussing. It's not so much "Do It Yourself" as "Someone Else Did
Most Of It For Me And Now I Just Paint By Numbers" (SEDMOIFMANIJPBN).
The reason why me and my ilk have to read your articles is because we
are in fact NOT skilled enough to concieve and design these things. We
can however build them. But since we are already pampered rather
heavily it feels ardenous to have to make the final set of decisions
ourselves (housing).


> This is a perfectly good example of a project that you could develop
> yourself. All you need to do is understand what you need to
> accomplish. Package it as pretty or as ugly as you wish.

But I don't want to develop it myself. I want to pay YOU to do it. I
want you to guide me through the design in the assembly notes,
explaining what each thing does, why this is good design practice etc.
So that at the end of assembling I may have learnt something. That's
ALL I want.
If I wanted to become an audio equipment designer of such a caliber
that I could design these things myself then I would study to become
one and not waste time trying to deduct something from a paint by
numbers DIY project.
Anonymous
November 14, 2004 7:09:36 PM

Archived from groups: rec.audio.pro (More info?)

"Paul Stamler" <pstamlerhell@pobox.com> wrote in message news:p k9ld.891630

> Approximate costs are as follows. These include everything except the
> cases,
> which are up to you. At the moment I'm assuming the PC boards would cost
> $25.00 / ea.;


Good so far ....

that's the biggest unknown in the equation. I can't really
> fill that in until I design the boards, and I'm not gonna do that until I
> find out whether anybody's interested. (Also, of course, price of the
> boards
> will vary depending on how many I order.) There are options which will
> raise
> the price, and some that will lower it, but this is the basic design.
>
> Each input channel: $220.00

What is in it that bumps up the cost this much ? Maybe transformer, stepped
swtich, platinum op-amps ?


> Power Supply: $120.00

I'm so would supply own transformer....

> Any interest?

Yep, in the cct board !


geoff
Anonymous
November 14, 2004 7:11:04 PM

Archived from groups: rec.audio.pro (More info?)

"agent86" <maxwellsmart@control.gov> wrote in message
news:1aeld.10637$WC6.2348@bignews3.bellsouth.net...
> Mike Rivers wrote:
>
>> I think that the average DIYer today would find that to be too much
>> cash to put into a project, particularly since it involves a case and
>> considerable metalworking skill to make a unit that looks decent.
>
> Very true. With the RNP going for $475 new, what's the point (unless you
> just absolutely HAVE to have transformers). And why would you reall NEED
> transformers at that price point, since Shure 57s behave themselves pretty
> well with the RNP?


I'd be more interested in variable input impedence.

geoff
Anonymous
November 14, 2004 7:11:05 PM

Archived from groups: rec.audio.pro (More info?)

Geoff Wood wrote:

> I'd be more interested in variable input impedence.

Which reminds me of a question that came up on another
forum. Seems that pre impedences are down in the 2K Ohm and
below range. Have they always been that low and why such a
relatively big load?


Bob
--

"Things should be described as simply as possible, but no
simpler."

A. Einstein
!