Op amp advice

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

For you op-amp experts I need some advice...

Just got a new (old) mixing console, Peavey/AMR 2400, and there is a
noticeable level of noise in the master module when I pull up the faders,
even though there is no signal from any of the channels. I called Peavey's
tech dept and they suggested replacing the op-amps in the master module, as
they age they lose their tolerances and can cause noise (it sounds like
white noise). The manual shows that it contains a bunch of 5532's, a few TL
074's, a few TL 072's, and a 741. I did a search at Digikey's website, and
found that there seems to be many "versions" of each chip, each with a
difference suffix to the chip number. I can physically replace the chips,
but determining the right version is beyond my expertise.

What would the difference be for each version, and which do you think would
be best for my application Or would it really matter? Tried Google for the
answer but not finding anything concrete.

Thanks in advace,

Matt

--
---
Matt Macchiarolo
mlmacchiarolo at comcast dot net
AIM screen name RTI1182

"We must not confuse dissent with disloyalty." -Edward R. Murrow

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

On Sat, 13 Nov 2004 15:45:26 +0000, Pooh Bear
<rabbitsfriendsandrelations@hotmail.com> wrote:

>Matt Macchiarolo wrote:
>
>> For you op-amp experts I need some advice...
>>
>> Just got a new (old) mixing console, Peavey/AMR 2400, and there is a
>> noticeable level of noise in the master module when I pull up the faders,
>> even though there is no signal from any of the channels. I called Peavey's
>> tech dept and they suggested replacing the op-amps in the master module, as
>> they age they lose their tolerances and can cause noise (it sounds like
>> white noise).
>
>That's total rubbish.
>
>I'd only expect on op-amp to go noisy if there was a manufacturing or
>encapsualation defect.
>
>> The manual shows that it contains a bunch of 5532's, a few TL
>> 074's, a few TL 072's, and a 741. I did a search at Digikey's website, and
>> found that there seems to be many "versions" of each chip, each with a
>> difference suffix to the chip number. I can physically replace the chips,
>> but determining the right version is beyond my expertise.
>
>The suffixes relate to commercial / industrial / military temperature range and
>the package ( dual in line / SMT etc ).
>
>TL072s in this product are likely to be TL072CP in TI ( Texas Instruments who
>originated them ) speak - commercial plastic 8 pin dil - but the suffixes vary
>from manufacturer to manufacturer.
>
>
>> What would the difference be for each version, and which do you think would
>> be best for my application Or would it really matter? Tried Google for the
>> answer but not finding anything concrete.
>
>Well you need the commercial type in the same package as you want to replace.
>
>I don't expect you're going to go anywhere with this though. Old products
>didn't have today's noise specs and it isn't just the op-amps. 'Thermal noise'
>from resistors can't be 'replaced out' for example. Older designs paid less
>attention to thermal noise issues.
>
>Peavey also weren't exactly known as great mixing console makers, so don't
>expect too much anyway.
>
>The 5532 is actually quite quiet and is still in very regular use. TL072s are
>somewhat noisier by todays's standards but still have their applications.
>
>Random replacement really isn't going to buy you much. You'd have to find the
>noisiest areas and substitute better parts to be honest ( assuming that it
>would make a difference over the thermal noise ).
>
>
>Graham
>
Further to Grahams's excellent advice, I will make some slightly
educated guesses:

The noise was always there. Our expectations have gotten higher.

The first op-amp in the channel, with the smallest (mic level) input
signal, is the biggest contributor to the noise. If it's a TL072,
consider replacing it with a newer, quieter design.

Do any of our experts have a suggestion for a TL072 replacement in
this application? I'm not familiar with the schematic of this mixer,
so I won't even venture a guess.

Mike T.

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

"Mike T." wrote:

> On Sat, 13 Nov 2004 15:45:26 +0000, Pooh Bear
> <rabbitsfriendsandrelations@hotmail.com> wrote:
>
> >Matt Macchiarolo wrote:
> >
> >> For you op-amp experts I need some advice...
> >>
> >> Just got a new (old) mixing console, Peavey/AMR 2400, and there is a
> >> noticeable level of noise in the master module when I pull up the faders,
> >> even though there is no signal from any of the channels. I called Peavey's
> >> tech dept and they suggested replacing the op-amps in the master module, as
> >> they age they lose their tolerances and can cause noise (it sounds like
> >> white noise).
> >
> >That's total rubbish.
> >
> >I'd only expect on op-amp to go noisy if there was a manufacturing or
> >encapsualation defect.
> >
> >> The manual shows that it contains a bunch of 5532's, a few TL
> >> 074's, a few TL 072's, and a 741. I did a search at Digikey's website, and
> >> found that there seems to be many "versions" of each chip, each with a
> >> difference suffix to the chip number. I can physically replace the chips,
> >> but determining the right version is beyond my expertise.
> >
> >The suffixes relate to commercial / industrial / military temperature range and
> >the package ( dual in line / SMT etc ).
> >
> >TL072s in this product are likely to be TL072CP in TI ( Texas Instruments who
> >originated them ) speak - commercial plastic 8 pin dil - but the suffixes vary
> >from manufacturer to manufacturer.
> >
> >
> >> What would the difference be for each version, and which do you think would
> >> be best for my application Or would it really matter? Tried Google for the
> >> answer but not finding anything concrete.
> >
> >Well you need the commercial type in the same package as you want to replace.
> >
> >I don't expect you're going to go anywhere with this though. Old products
> >didn't have today's noise specs and it isn't just the op-amps. 'Thermal noise'
> >from resistors can't be 'replaced out' for example. Older designs paid less
> >attention to thermal noise issues.
> >
> >Peavey also weren't exactly known as great mixing console makers, so don't
> >expect too much anyway.
> >
> >The 5532 is actually quite quiet and is still in very regular use. TL072s are
> >somewhat noisier by todays's standards but still have their applications.
> >
> >Random replacement really isn't going to buy you much. You'd have to find the
> >noisiest areas and substitute better parts to be honest ( assuming that it
> >would make a difference over the thermal noise ).
> >
> >
> >Graham
>
> Further to Grahams's excellent advice, I will make some slightly
> educated guesses:
>
> The noise was always there. Our expectations have gotten higher.

Pretty likely !


> The first op-amp in the channel, with the smallest (mic level) input
> signal, is the biggest contributor to the noise. If it's a TL072,
> consider replacing it with a newer, quieter design.

EEEK !!! I hope no mic stage goes straight into a TL07x. You *should* find some
transistors there. I'm pretty certain it won't be a transformer input mic stage btw
( cost reasons ).


> Do any of our experts have a suggestion for a TL072 replacement in
> this application? I'm not familiar with the schematic of this mixer,
> so I won't even venture a guess.

I was trying to think of one. There's nothing in the 'commodity' ( i.e. affordable !
) IC market that I can think of immediately that is also bi-fet but I have a
nagging feeling somewhere there's something with a *slightly* lower noise figure.
Don't use bi-fets much these days,!

The more esoteric devices from Burr-Brown ( now TI ) and Analog Devices will have
lower noise figures for sure.

Thing is - there's no guarantee that there'll be a useful improvement until you
diagnose the root cause of the noise sources. You could end up spending more bucks
than a new Behringer costs.


Graham

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

Thanks for all the advice, folks.

Channel faders are all down. I am still in the process of connecting the
console to the rest of the studio, but I did get a mix through it, and
that's when I noticed the noise.

The noise seems to be only coming from the master module, the input channels
are actually pretty quiet. According to the previous owner, the master
module was affected with a power surge at one time that blew out the fuse
resistors in the power input circuit to the module...could this have
affected the op amps as well?

"William Sommerwerck" <williams@nwlink.com> wrote in message
news:10pchf7dlorcgdc@corp.supernews.com...
> > Just got a new (old) mixing console, Peavey/AMR 2400,
> > and there is a noticeable level of noise in the master
> > module when I pull up the faders, even though there is
> > no signal from any of the channels.
>
> Where are the channel faders? Are they all the way up/down, or at "normal"
> operating positions?
>
> Almost any electronics will produce audible noise under the "wrong"
conditions.
> Is everything (including your monitor amps) set up as it would be when
making a
> recording?
>

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

> According to the previous owner, the master module was affected
> with a power surge at one time that blew out the fuse resistors in
> the power input circuit to the module... could this have affected
> the op amps as well?

I don't know, but such a failure calls for some careful troubleshooting (such as
using an AC voltmeter to see if one stage is particularly noisy).

Assuming the master module uses inexpensive tab-case regulators, it wouldn't
hurt to replace them. Whether a wholesale replacement of other components is
justified, I don't know.

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

Paul Stamler wrote:

> "Mike T." <miket@invalid.net> wrote in message
> news:nadcp01i2kmtvc6gcciitt0nndqi61toik@4ax.com...
>
> >> Further to Grahams's excellent advice, I will make some slightly
> > educated guesses:
> >
> > The noise was always there. Our expectations have gotten higher.
> >
> > The first op-amp in the channel, with the smallest (mic level) input
> > signal, is the biggest contributor to the noise. If it's a TL072,
> > consider replacing it with a newer, quieter design.
> >
> > Do any of our experts have a suggestion for a TL072 replacement in
> > this application? I'm not familiar with the schematic of this mixer,
> > so I won't even venture a guess.
>
> I don't know the schematic of this mixer either, but I'd guess that the
> TL072 isn't the first opamp in the chain; that's probably a 5532.
>
> But I'm not clear on one thing: you heard the noise just pushing up the
> master faders, or pushing up the master *and* the channel faders? If the
> latter, what was plugged into the inputs?
>
> If the answer is, "Nothing", then try this experiment. Push up the master
> and one channel fader. Listen to and/or measure the noise. Now pull down the
> channel fader and plug a dummy XLR plug into the microphone input, with a
> 150-ohm metal film resistor soldered between pins 2 and 3. Push the fader
> back up. If the noise is a lot less, stop worrying. You were hearing the
> sound of an open-circuit input, which will almost always be worse than one
> with something plugged in. And since you won't be opening a fader on a
> channel with nothing plugged into it, you can relax.

Good point.

I'm aware that many 'music / guitar shops' make exactly this kind of mistake
when demoing mixers.

They say " you're mixer's noisy ". Actually of course - it's the absence of the
150-200 ohm source resistance that makes the circuit noisy as we know. But
*they* don't get it.

Graham

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

Scott Dorsey wrote:

> Eric K. Weber <eric-nospam@webermusic.com> wrote:
> >Have a look at www.ti.com , they may be different package styles or
> >temperature ranges. Op amps getting noisy with age seems unlikely....
> >although there might be lower noise units that are pin compatible. You may
> >wish to check the power supply noise level.... With your meter on AC
> >millivolts measure the ripple on your DC power supply.... less than 10 MV
> >should be expected... good supply run about 2 MV for a 24VDC or lower
> >supply.
>
> TI never could make decent op-amps. While it does seem very unlikely,
> I could see op-amps getting noisy as they age if they have package
> contamination problems... and if anyone has package contamination issues,
> it would be TI. They had to buy out Burr-Brown because they couldn't make
> decent linear stuff in-house.

A certain person I know reputedly bought a batch of 'cheap' TL071/2s that
allegedly may have been immersed in salt water ( salvaged cargo ).

They went noisy it seems !


Graham

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

It's just the master faders. No channel faders are up.

"Pooh Bear" <rabbitsfriendsandrelations@hotmail.com> wrote in message
news:41965AC5.10E3F8CA@hotmail.com...
> Paul Stamler wrote:
>
> > "Mike T." <miket@invalid.net> wrote in message
> > news:nadcp01i2kmtvc6gcciitt0nndqi61toik@4ax.com...
> >
> > >> Further to Grahams's excellent advice, I will make some slightly
> > > educated guesses:
> > >
> > > The noise was always there. Our expectations have gotten higher.
> > >
> > > The first op-amp in the channel, with the smallest (mic level) input
> > > signal, is the biggest contributor to the noise. If it's a TL072,
> > > consider replacing it with a newer, quieter design.
> > >
> > > Do any of our experts have a suggestion for a TL072 replacement in
> > > this application? I'm not familiar with the schematic of this mixer,
> > > so I won't even venture a guess.
> >
> > I don't know the schematic of this mixer either, but I'd guess that the
> > TL072 isn't the first opamp in the chain; that's probably a 5532.
> >
> > But I'm not clear on one thing: you heard the noise just pushing up the
> > master faders, or pushing up the master *and* the channel faders? If the
> > latter, what was plugged into the inputs?
> >
> > If the answer is, "Nothing", then try this experiment. Push up the
master
> > and one channel fader. Listen to and/or measure the noise. Now pull down
the
> > channel fader and plug a dummy XLR plug into the microphone input, with
a
> > 150-ohm metal film resistor soldered between pins 2 and 3. Push the
fader
> > back up. If the noise is a lot less, stop worrying. You were hearing the
> > sound of an open-circuit input, which will almost always be worse than
one
> > with something plugged in. And since you won't be opening a fader on a
> > channel with nothing plugged into it, you can relax.
>
> Good point.
>
> I'm aware that many 'music / guitar shops' make exactly this kind of
mistake
> when demoing mixers.
>
> They say " you're mixer's noisy ". Actually of course - it's the absence
of the
> 150-200 ohm source resistance that makes the circuit noisy as we know. But
> *they* don't get it.
>
> Graham
>

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

"Pooh Bear" <rabbitsfriendsandrelations@hotmail.com> wrote in message
news:41965D7A.9B3592BC@hotmail.com...

>
> What's the 741 doing btw ?
>

Don't have the slightest idea, reading schematics is like Greek to me.
Though it's there and there is only one. Perhaps something to do with the
mono switch?

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

Matt Macchiarolo wrote:

> "Pooh Bear" <rabbitsfriendsandrelations@hotmail.com> wrote in message
> news:41965D7A.9B3592BC@hotmail.com...
>
> >
> > What's the 741 doing btw ?
> >
>
> Don't have the slightest idea, reading schematics is like Greek to me.
> Though it's there and there is only one. Perhaps something to do with the
> mono switch?

If you have the schematics - can you scan them ( master section a tleast )
and post in alt.binaries.schematics.electronics ?

I'll take a look. Would be able to advise better.


Graham

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

I don't have a scanner, got a fax machine?

"Pooh Bear" <rabbitsfriendsandrelations@hotmail.com> wrote in message
news:419669EF.54C938CF@hotmail.com...
>
> Matt Macchiarolo wrote:
>
> > "Pooh Bear" <rabbitsfriendsandrelations@hotmail.com> wrote in message
> > news:41965D7A.9B3592BC@hotmail.com...
> >
> > >
> > > What's the 741 doing btw ?
> > >
> >
> > Don't have the slightest idea, reading schematics is like Greek to me.
> > Though it's there and there is only one. Perhaps something to do with
the
> > mono switch?
>
> If you have the schematics - can you scan them ( master section a tleast )
> and post in alt.binaries.schematics.electronics ?
>
> I'll take a look. Would be able to advise better.
>
>
> Graham
>
>

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

"Pooh Bear" <rabbitsfriendsandrelations@hotmail.com> wrote in message
news:41966C94.8848FA35@hotmail.com...
>
> Matt Macchiarolo wrote:
>
> > I don't have a scanner, got a fax machine?
>
> Yup.
>

Fax is transmitting. I won't give out your fax number. :-)

741 is in section A-4 of the lower schematic (Left Bus).

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

So I am learning.

"Mike Rivers" <mrivers@d-and-d.com> wrote in message
news:znr1100362543k@trad...
>
> In article <tPCdnQ1GnOAzhQvcRVn-sQ@comcast.com> matt@nospamplease.com
writes:
>
> > Just got a new (old) mixing console, Peavey/AMR 2400, and there is a
> > noticeable level of noise in the master module when I pull up the
faders,
> > even though there is no signal from any of the channels. I called
Peavey's
> > tech dept and they suggested replacing the op-amps in the master module,
as
> > they age they lose their tolerances and can cause noise (it sounds like
> > white noise).
>
> Yeah, Peavey's advice sounds like white noise, or just plain horse
> manure. I've never heard of op amps that "age" and "lose their
> tolerance." More likely it's a bad resistor, a bad capacitor, a bad
> switch, or a bad solder joint. Could even be a dirty connector
> contact. While there may be better sounding op amps available today,
> take care of the real source of the noise first or you'll still have
> it after you replace the chips.
>
>
> --
> 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

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

Thanks Pooh! Next time I'm in the UK I will buy you a pint of Greene King!
Until then I will raise a glass of Old Speckled Hen to you!

Both schematics are on one page, 8.5x11...fairly tiny.

Those op amps are U1A and U1B, a=left b=right. . Those are the summing amps,
correct? You don't think the U5's (section D-4) could be a factor? All those
are 5532's. The manual includes a PCB diagram so I can find those pretty
easily.

If you were to replace those resistors, what would you recommend?

And what does that 741 do?
"Pooh Bear" <rabbitsfriendsandrelations@hotmail.com> wrote in message
news:41967593.7EBCA191@hotmail.com...
>
> Matt Macchiarolo wrote:
>
> > "Pooh Bear" <rabbitsfriendsandrelations@hotmail.com> wrote in message
> > news:41966C94.8848FA35@hotmail.com...
> > >
> > > Matt Macchiarolo wrote:
> > >
> > > > I don't have a scanner, got a fax machine?
> > >
> > > Yup.
> >
> > Fax is transmitting. I won't give out your fax number. :-)
> >
> > 741 is in section A-4 of the lower schematic (Left Bus).
>
> Ok - got it.
>
> Is that the size you got it ? A bit on the tiny side. Having trouble
> reading it.
>
> The good news is that the 741 clearly isn't in the audio path ( as I
> suspected ).
>
> I'm having trouble reading the U numbers but the ICs for the bus amps are
> the ones ( one on each page ) that are on the top left hand corner - note
> the connections to BUS GND and a 10UH inductor. Looks like one half of
> the dual op-amp is the bus amp - the other half is the fader buffer -
> pretty classic.
>
> If *anything* is going to make a difference - it's them !
>
> The resistor values around the bus amps aren't *too* bad regarding
> thermal noise but I would use lower. But that's a re-design.
>
>
> Graham
>
>
>
>
>

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

Matt Macchiarolo wrote:

> Thanks Pooh! Next time I'm in the UK I will buy you a pint of Greene King!
> Until then I will raise a glass of Old Speckled Hen to you!

Cheers then !


> Both schematics are on one page, 8.5x11...fairly tiny.
>
> Those op amps are U1A and U1B, a=left b=right. . Those are the summing amps,
> correct?

Ok - wondered if that might be so.

> You don't think the U5's (section D-4) could be a factor? All those
> are 5532's. The manual includes a PCB diagram so I can find those pretty
> easily.

The other op-amps operate at high signal levels so the noise contribution there
won't be an issue.

No need to replace.

> If you were to replace those resistors, what would you recommend?

Well, I'd most likely use something like 4k7 feedback Rs in place of 22k. You
can't do that without altering the channel values though or the gain structure
gets screwed.


> And what does that 741 do?

Given the quality of the fax it's tricky to say. Is there a peak led there
though. Maybe that's it ?

TI's part number for the DIL 5532 is NE5532AP btw.

http://focus.ti.com/docs/prod/fold [...] 5532a.html - log in as a tech and
request samples !

Philips / Signetics have stopped making it. NJR / JRC ( New Japan Radio
Corporation ) also source it.


Graham

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

I'll swap out those 5532's poohbear indicated, and see if it helps...I'll
try the power supply if that doesn't help. Though if it was a power supply
issue it would probably be evident on all channels, and it doesn't seem to
be.

"Eric K. Weber" <eric-nospam@webermusic.com> wrote in message
news:T8vld.26$a91.4552@news.uswest.net...
> Is this noise the same on both channels.... if so it's more likely either
a
> power supply issue or a design issue.
>
> Rgds:
> Eric
>
> "Pooh Bear" <rabbitsfriendsandrelations@hotmail.com> wrote in message
> news:419661E3.49193E00@hotmail.com...
> >
> > Matt Macchiarolo wrote:
> >
> > > It's just the master faders. No channel faders are up.
> >
> > Ok - sounds like noisy bus amps.
> >
> > Most likely a / some 5532s. There's going to be some circuitry following
> them
> > though that could also be influencing things.
> >
> > If you can identify the op-amp that's the bus mix section - then
selective
> > replacement as a test would make sense.
> >
> > I guess it's possible a chip's gone noisy - but it's rare. Maybe the
> Peavey guys
> > know something they're not letting on about ?
> >
> >
> > Graham
> >
> >
>
>

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

It should scale to A4 with no problem.... and if he is calling from the
USA.. it's

011 44 1727 765452

011 international prefix...
44 UK country code....

Rgds:
Eric

"Pooh Bear" <rabbitsfriendsandrelations@hotmail.com> wrote in message
news:41966C94.8848FA35@hotmail.com...
>
> Matt Macchiarolo wrote:
>
> > I don't have a scanner, got a fax machine?
>
> Yup.
>
> My bad to post it here but here goes ( dial international access ) ( then
UK
> code - 44 ) followed by 1727 then 765452.
>
> Plain paper fax btw. Only understands A4 ( international ) paper size -
not some
> of the funny US sizes. Try one page first to see how it goes.
>
>
> Graham
>
>

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

Well I just pulled the master module and it looks like it has been modded..
the 5532 in question seems to have been replaced with an LT1358, and some of
the others were replaced with TLE2082's, along with some other components
that were added. This console had 5 input channels modified by Audio
Upgrades, it looks as if the master module has been modified as well...looks
like I'll be calling Jim again.

Thanks for everyone's help!

Matt

"Matt Macchiarolo" <matt@nospamplease.com> wrote in message
news:T9ydnTbcLIFoGQvcRVn-gA@comcast.com...
> > > Those op amps are U1A and U1B, a=left b=right. . Those are the summing
> amps,
> > > correct?
> >
> > Ok - wondered if that might be so.
>
> According to the signal path diagram, they correspond to the summing amps.
> >
> > > You don't think the U5's (section D-4) could be a factor? All those
> > > are 5532's. The manual includes a PCB diagram so I can find those
pretty
> > > easily.
> >
> > The other op-amps operate at high signal levels so the noise
contribution
> there
> > won't be an issue.
> >
> > No need to replace.
> >
> > > If you were to replace those resistors, what would you recommend?
> >
> > Well, I'd most likely use something like 4k7 feedback Rs in place of
22k.
> You
> > can't do that without altering the channel values though or the gain
> structure
> > gets screwed.
>
> Gotcha.
> >
> >
> > > And what does that 741 do?
> >
> > Given the quality of the fax it's tricky to say. Is there a peak led
there
> > though. Maybe that's it ?
> >
> Ah yes, that makes sense to be the signal/peak LED circuit, it uses a
> bicolor LED that is green with signal and red when within 3dB of clipping,
> according to the manual...
>
> When I get a chance I'll swap out those 5532's and we'll see what
> happens...thanks for all your help!!
>
>
>

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

"Matt Macchiarolo"
> For you op-amp experts I need some advice...
>
> Just got a new (old) mixing console, Peavey/AMR 2400, and there is a
> noticeable level of noise in the master module when I pull up the faders,
> even though there is no signal from any of the channels.


** Bet you have selected every mic channel simultaneously - right ?

Bet you have the monitor speakers next to your ears in a quiet room -
right ?

Bet you have a monitor amp with less than 1 volt input sensitivity -
right ?


Do I sound just a bit cynical ?????

Yep - cos I just spent hours, at the owners insistence, removing a faint
buzzing noise from a studio monitor amp that ONLY EXISTED when the input was
open circuit !!!!!





................. Phil

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

"Matt Macchiarolo"
>
> "Phil Allison"
>> >
>> > Just got a new (old) mixing console, Peavey/AMR 2400, and there is a
>> > noticeable level of noise in the master module when I pull up the
> faders, even though there is no signal from any of the channels.
>>
>>
>> ** Bet you have selected every mic channel simultaneously - right ?
>>
>> Bet you have the monitor speakers next to your ears in a quiet
> > room - right ?
>>
>> Bet you have a monitor amp with less than 1 volt input
>> sensitivity - right ?
>>

> No, no and no.


** So you selected no mic channels at all ???

Have the speakers miles away in a noisy room ????

Have an amp with more than 1 volt sensitivity ?????


> See the rest of this thread.



** The answers to my simple questions are not there.





.............. Phil

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

"Matt Macchiarolo"
>
> Well I just pulled the master module and it looks like it has been
> modded..
> the 5532 in question seems to have been replaced with an LT1358, and some
> of
> the others were replaced with TLE2082's, along with some other components
> that were added.



** The LT1358 and TLE2082 are not low noise ICs - they are high speed
ones.

Some audiophool "gong beater" has been let loose at the desk.






............. Phil

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

"Pooh Bear"
>
> Matt Macchiarolo wrote:
>
>> No, no and no. See the rest of this thread.
>
> Don't bother abour Phil, he's our resident rodent / troll.
>


** Says a pathetic pommy wanker who *failed to ask* the basic questions and
so wasted a lot of ASCII.


> He loves to jump to conclusions based on everyone else being stupider than
> him


** See above - the Pooh Brain just proved that assumption was good again.






.............. Phil

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

"Matt Macchiarolo"

>>
>> Don't bother abour Phil, he's our resident rodent / troll.
>
> Every group seems to have one.
>



** This NG consists of virtually 100 % trolls.

Trolls with names like Dorsey, Rivers, Cain, Ford, Shaw and a cast of
thousands of know nothings.





............ Phil

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

Phil Allison wrote:

> "Matt Macchiarolo"
> >
> > Well I just pulled the master module and it looks like it has been
> > modded..
> > the 5532 in question seems to have been replaced with an LT1358, and some
> > of
> > the others were replaced with TLE2082's, along with some other components
> > that were added.
>
> ** The LT1358 and TLE2082 are not low noise ICs - they are high speed
> ones.
>
> Some audiophool "gong beater" has been let loose at the desk.
>
> ............ Phil

Yup.

I just said as much. Actually, the LT1358 is similar to the NE5532 noise wise
but it's not a part I'd commend for audio.

Good to see you agree.


Graham

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

Matt Macchiarolo wrote:

> "Pooh Bear" <rabbitsfriendsandrelations@hotmail.com> wrote in message
> news:4196ABE2.FD8239CA@hotmail.com...
> >
> > Matt Macchiarolo wrote:
> >
> > > No, no and no. See the rest of this thread.
> >
> > Don't bother abour Phil, he's our resident rodent / troll.
>
> Every group seems to have one.

He's a classic !

Shame really since he's quite knowledgeable. Thing is - he has no
personal ...... errrrrr .. anything

No redeeming features. He just likes to pop shots at others.

Gets boring.

Anyway - I suggest you replace your ICs with the original parts
specified. It may sound better then.

You might also care to kick the arse of the bloke who sold it to you !

The schematics suggest it's one of Peavey's better consoles btw.



Graham