Help needed with multi-speaker amp project

[steve1977]

Hello,

First post on the forum, thanks for having me.
I'm a fairly experienced audio person, but new to the electronic/circuit side of things.
Basically, I have to set up an audio experiment for a PhD.
9 streams of independent audio are to be fed to 9 different small speakers in a room.
The streams will all come from different tracks on a laptop/daw, which will all be routed to a separate buss, which will be sent to a focusrite interface and outputted via 9 different TRS output leads.
The experiment will look like the figure below.

I have the 9 small passive speakers already . My only problem is that I need to build an amplifier (in the illustration, the sky blue box) to power the 9 different passive speakers.
I've never built an amp before, but I can find plenty of single-channel 1W diagrams that I should be able to follow.
Such as the one below.

My idea is to have a rack-mounted 1U 19" box, containing 9 individual amp channels, but with 9x TRS jack inputs and 9x speaker outputs, while doing away with the 9v batteries.
My questions are mainly about power. Powering each individual channel with a 9v battery may not be convenient as the experiments may last a long time.
Would it be simple enough to build 9 x channels (as above), but instead of batteries then link them all to a mains power source, and if so, does anyone have any diagrams of a similar design I could study?
Failing that, if anyone has any advice, ideas or can see a glaring error in my thinking, then please let me know.

Many thanks.

Steve

 

[LTig]

What are the requirements for one channel amp? Power, Load come to my mind. Do you jeed to build it or is buying an option? What's the budget for all?

 

[steve1977]

What are the requirements for one channel amp? Power, Load come to my mind. Do you jeed to build it or is buying an option? What's the budget for all?

I think 1W per channel will be fine, the speakers are all 8ohms

FR 10 HM - 8 Ohm | Visaton

10 cm (4") fullrange speaker with tweeter cone and European standard basket. Simple fitting in vehicles with cut-outs for 10 cm speakers.

www.visaton.de

I'd like to build it if at all possible, as all the grant money has gone elsewhere!

 

[LTig]

I think 1W per channel will be fine, the speakers are all 8ohms

I'd like to build it if at all possible, as all the grant money has gone elsewhere!

What about a simple amp based on the TDA2003? I found this one (sorry, German language) for less than € 10. With a matching power supply (15 V/ 4A) and a decent housing (19" ?) costs may be around € 200 for 8 amps.

 

[steve1977]

What about a simple amp based on the TDA2003? I found this one (sorry, German language) for less than € 10. With a matching power supply (15 V/ 4A) and a decent housing (19" ?) costs may be around € 200 for 8 amps.

Thanks for that, looks great.
So, I'd just need to add the trs jack inputs and, my other question is , instead of each of the 9 channels having their own 15v power supply, and 9 plugs, could it be wired so there's only one master mains plug?

 

[LTig]

Yes.

 

[steve1977]

Yes.

Ok, that's great, thank you. This is the part where I'm struggling as I'm still new to circuits. I'm not exactly sure how I link the power up.
Could you tell me if I'm on the right lines here...(I'd be amazed if I was)
Do I...Get a large breadboard, install 9 x of the amps you suggested (K4001 kit), then I add on 9x TRS inputs (TRS inputs), then (and this is the bit where I'm especially fuzzy) do I take the twin power wires from each of the 9 amps and connect it to a Power distribution board (Power Distribution )..then take the output from the PDB and connect to a DC adapter input (Female DC input), then just power from a 12v AC/DC wall adapter.
Would that work?

 

[LTig]

Yes with one exception. The power supply must be able to deliver 9 x 0.5A = 4.5 A which is too much for this DC input, I think. Find a matching power supply and use whatever connection it offers.

Edit: this one is quite cheap but you must put it into the housing with the amps (or a separate one) and if you're not familiar with line voltages get someone with experience to do it for you.

Another possibility is to use two weaker wall adapters like this one. One feeds 4 channels the other 5 channels.

 

[steve1977]

Thank you so much for your help

 

[steve1977]

Yes with one exception. The power supply must be able to deliver 9 x 0.5A = 4.5 A which is too much for this DC input, I think. Find a matching power supply and use whatever connection it offers.

Edit: this one is quite cheap but you must put it into the housing with the amps (or a separate one) and if you're not familiar with line voltages get someone with experience to do it for you.

Another possibility is to use two weaker wall adapters like this one. One feeds 4 channels the other 5 channels.

Could something like this work?

12V 5A power supply

 

[LTig]

I checked the datasheet. It's stable from 0 A (no load) to 5 A, safe against over voltage and short cuts and has a ripple of 120 mV. I think this is OK.