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diy 10 channel amp for art installation?

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Anonymous
February 24, 2005 12:31:11 PM

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

I am trying to figure out the best way to power ten 3" speakers for an
audio installation project that I am working on.

I have an audio card that has 10 outputs (5 stereo outs) and need to be
able to feed these signals to the 10 speakers. I have been looking
around various newsgroups and websites to figure out the best way to
tackle this. I don't have much experience with circuits (I am a
programmer), but I am willing to learn whatever I need to make this
happen. If building something would be prohibitively difficult and/or
expensive, I am also willing to purchase something that would do the
job. I don't have much money to spend on this, though.

Any pointers or links to information would be very much appreciated.

When I'm done with this, I'll post pictures/explanations for anyone
that is interested.

Many, many thanks.

stevie
Anonymous
February 25, 2005 3:02:32 PM

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

"steviec" <steviec@gmail.com> writes:

> I am trying to figure out the best way to power ten 3" speakers for an
> audio installation project that I am working on.
>
> I have an audio card that has 10 outputs (5 stereo outs) and need to be
> able to feed these signals to the 10 speakers. I have been looking
> around various newsgroups and websites to figure out the best way to
> tackle this. I don't have much experience with circuits (I am a
> programmer), but I am willing to learn whatever I need to make this
> happen. If building something would be prohibitively difficult and/or
> expensive, I am also willing to purchase something that would do the
> job. I don't have much money to spend on this, though.
>
> Any pointers or links to information would be very much appreciated.
>
> When I'm done with this, I'll post pictures/explanations for anyone
> that is interested.

You have not listed specifications like how much power you need
for those speakers and what is the price range of the system.

Here are some ideas that come to my mind how this could be done:

1. Buy or sent five stereo PA amplifiers and put then to a suitable
rack or just stack them on top of each other
- built using ready made components
- this is a way to go if you need lots of power
- price range depends on the power range, statring from
somethign like 150-200 Euros/dollars per amplifier
Some examples:
http://www.netzmarkt.de/thomann/alesis_ra150_prodinfo.h...
http://www.netzmarkt.de/thomann/the_tamp_ta450ii_endstu...

2. Get ten one channel amplifier modules, install then all to
one place or put them where the speakers are
- price range stats form something like 50-60 Euros/dollars per module
Some examples:
http://www.netzmarkt.de/thomann/the_tamp_pm40c_endstufe...

3. Get two home hifi AV amplifier (5.1 channel amplifiers) that have
analogue 5.1 channel input
- use first amplifier to drive five speakers and second the rest
- the price range start from something like 300-400 euros/dollars per
amplifier (unless you can find some really cheap deal)

4. Get some amplifier electronics kits, build suitable power supply
for them and put them to suitable case
- you need to know about electronics to do this safely
- if you can find cheap kits and do not need lots of power
could be economical, on high power system definatelu not worh of the
problem because chinese made PA amplifiers are available very cheaply
(building the same based on kits is more expensive)

5. Get five cheap car stereo amplifiers and power supply for them
- could be useful on quite low poer system if you can get cheap
car amplifiers
- please not that the power rating on cheap car amplifiers might not
tell truth (they give out considerably less power out than they promise)
- the high power 12V power supply needed to power those amplifiers
is a considerably expensive

Those are my ideas.



--
Tomi Engdahl (http://www.iki.fi/then/)
Take a look at my electronics web links and documents at
http://www.epanorama.net/
Anonymous
February 26, 2005 8:22:47 PM

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

If eight watts per channel is OK then I would use the little
power-amp-on-an IC that looks like a regulator IC with more pins. They
mount on a plate with a plastic bolt and a mica or rubber insulator
with a little thermal paste. This is sold as a Gaincard/Gainclone to hi
fi people and some like it.
Anonymous
February 27, 2005 5:33:25 PM

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

I have auditioned Gainclones with a couple of relatively efficient
speakers including my own LaScalas. They are , as I expected, somewhat
dull sounding with poor articulation and snarky sibilants. However,
considering that they are a single little speck of silicon costing a
tiny amount to produce, that they are even the amplifier they are is
remarkable. I had them at the same time as I had the homebrew (someone
else's) WE91 clones and the comparison was interesting. Power output
from 100 Hz to 10 KHz was about the same. Measured THD was better on
the Gainclone. Overall which was better? For full range music, the
Gainclone. However female vocals where you only really cared about the
voice of the singer, the WE91 had an edge. But not that much.

I believe NatSemi could do better and when they do the results will be
more impressive. But for what they are the 3886 is pretty remarkable
and for many non-high-end applications are a clear-cut winner. The
question is whether enough buyers want really excellent as opposed to
okay sound. If they do and NatSemi apply themselves the results could
inspire a new era of DIY active speaker building. I don't see eight
watts as relevant for woofer driving but for tweeters could be
remarkable. Mcintosh's Power Guard patents run out in 2007 AFAIK so
this, or perhaps provision for use of feedback sense coils as found on
cutter heads in tweeter drivers, could be a big advance.
February 27, 2005 9:25:14 PM

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

calcerise@hotmail.com wrote:
> If eight watts per channel is OK then I would use the little
> power-amp-on-an IC that looks like a regulator IC with more pins. They
> mount on a plate with a plastic bolt and a mica or rubber insulator
> with a little thermal paste. This is sold as a Gaincard/Gainclone to hi
> fi people and some like it.

TDA2030 or something like it?
Anonymous
February 27, 2005 9:25:15 PM

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

"Sander" <Big_Scary_Man@hotmail.com> wrote in message
news:ypnUd.3475$Mw3.1186@amstwist00

> calcerise@hotmail.com wrote:
>> If eight watts per channel is OK then I would use the little
>> power-amp-on-an IC that looks like a regulator IC with more pins.
>> They mount on a plate with a plastic bolt and a mica or rubber
>> insulator with a little thermal paste. This is sold as a
>> Gaincard/Gainclone to hi fi people and some like it.

> TDA2030 or something like it?

Various sources place the active core of the Gaincard/Gainclone as being
either a LM3875 or LM3886.

Here are some other highly-respected source of info about LM3886 power amps:

http://www.linkwitzlab.com/images/graphics/3886amp.gif

http://www.national.com/pf/LM/LM3886.html

http://www.national.com/an/AN/AN-1192.pdf
Anonymous
February 28, 2005 10:36:59 AM

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

<calcerise@hotmail.com> wrote in message
news:1109543605.290631.130770@l41g2000cwc.googlegroups.com

> I have auditioned Gainclones with a couple of relatively efficient
> speakers including my own LaScalas. They are , as I expected, somewhat
> dull sounding with poor articulation and snarky sibilants.

Hmm, sounds like typical LaScala performance to me. I wouldn't blame the
amps for not automagically turning old has-been turkeys like the LaScalas
into something that would be competitive in the 21st century.

> However,
> considering that they are a single little speck of silicon costing a
> tiny amount to produce, that they are even the amplifier they are is
> remarkable.

Wow how out-of-date are you, Cal? It's perfectly reasonable to expect one of
these specs of silicon to put out significant amounts of clean power and
easily pass a straight-wire-bypass test.

> I had them at the same time as I had the homebrew (someone
> else's) WE91 clones and the comparison was interesting.

Only to a conservator in an audio museum.

>Power output from 100 Hz to 10 KHz was about the same. Measured THD was
better on
> the Gainclone.

I'd seriously hope so! BTW, any modern amp that can't best an ancient
turkey like a WE91 should be immediately repaired or trash-canned.

> Overall which was better? For full range music, the
> Gainclone. However female vocals where you only really cared about the
> voice of the singer, the WE91 had an edge. But not that much.

If female vocals are substandard in the WE91 test system, blame the
speakers, blame the amp, blame the recording, but don't blame modern
technology!

> I believe NatSemi could do better and when they do the results will
> be more impressive. But for what they are the 3886 is pretty
> remarkable and for many non-high-end applications are a clear-cut
> winner. The question is whether enough buyers want really excellent
> as opposed to okay sound.

As opposed to totally obsolete sound?

> If they do and NatSemi apply themselves the
> results could inspire a new era of DIY active speaker building. I
> don't see eight watts as relevant for woofer driving but for
> tweeters could be remarkable.

Cal's inability to discern the true capabilities of the 3886 noted. heck, I
posted a link to a 3886 AN with a 200 wpc amp described in detail on pp
12-13.

Here it is again for the learning-disabled:

http://www.national.com/an/AN/AN-1192.pdf

>Mcintosh's Power Guard patents run out
> in 2007 AFAIK so this, or perhaps provision for use of feedback sense
> coils as found on cutter heads in tweeter drivers, could be a big
> advance.
Anonymous
February 28, 2005 8:54:41 PM

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

My LaScalas perform very well with a variety of amplifiers, both tube
and solid state. I find they reveal the sonic faults of amplifiers all
too well. They are not the ultimate speaker but my listening room isn't
the ultimate listening room either. In general I like them but would be
the first to state that other speakers can elipse them in many
respects. Most are horn loaded to some extent and some use coax
drivers. These design concepts went away because of economics and not
sound.

The fact is that the admittedly shitty-read that phrase over again,
admittedly shitty- WE91, a terrible amplifier in many respects, did
certain things better than did the NatSemi chip. Not so many that I
would prefer it overall. But the fact is that on my LaScalas,through
the WEs you can hear Susannah McCorkle enunciate every word on her Leo
Robin album and with the Gainclones her sibilants sound snarky and
'queefy'. On Keely Smith's 'Keely Sings Sinatra', her rendition of
"My Way" (a song which I think unsuited to female singers anyway, but
beside the point) about half the chorus is mumblesville through the
gainclones and all too comprehensible through the 91s. The imaging of
this disc, like a lot of Concord Jazz releases, is a little surreal to
begin with and the 91s make them sound a little less artificial.

Amplifiers better than these make either one a less than desirable
choice but that, as with most things in life, is a point you are
apparently incapable of comprehending.

If you like the sound of five-way Boston Bland chimp coffins with foam
surrounded drivers being driven by amps more usually found in PA racks,
well, bully for you. However it differs in measurement, it doesn't
necessarily sound better.
!