Advice on Adafruit 2.8w Class D amplifiers


#1

Hi,

I’m working on an art project for which I need 6 independent channels of audio amplification. Adafruit TS2012 looks like what I need but even after visiting the Adafruit website I’m not clear on a few things.

  1. It looks as though using a breadboard is the simplest way to wire it up. Is it possible to wire up 3 amps side by side on the same breadboard? Would this create interference or problems with independent power?

  2. there’s reference to the amp having fully ‘differential’ outputs. what does this mean? I’ve never heard an amp described in these terms before

  3. a 5v, 2amp PSU is recommended and I notice that Adafruit make a product like this. However, would there be a problem with using an old USB hub? For powering 3 amps this would be neater and cheaper so I wonder why USB isn’t mentioned as a potential solution?

Many thanks in advance

David


#2
  1. I’d test on a breadboard and then solder the whole thing together on either protoboard or directly with wires. Breadboards are generally terrible for any kind of permanent setup since they fall apart, introduce noise and capacitance and additional failure points. I imagine this would be bad for audio.

  2. It’s probably not relevant for your setup, but the amplifier amplifies the difference between two input signals.

If you have a differential input ( like “balanced” XLR ) you can pass the two signals right into the amp and take advantages of the benefits of differential - IE: It’s amplifying the difference between the two signal lines, any noise introduced will generally be the same in each line so it wont get amplified.

If you have just one signal line per channel, you can just tie the R- or L- to ground, and the difference between ground and your input signal will be what’s amplified.

  1. I wouldn’t be confident in an old USB hubs ability to provide enough power, it really depends on the hub. This is also a fairly atypical use of a HUB, they’re not really designed to distribute power even if they do work. You’d also have to splice a bunch of USB cables to turn the USB ports into something you could connect to the amps.

I’d personally use a barrel jack adaptor and something like a 5v 4A mains supply: https://www.adafruit.com/products/1466


#3

Many thanks Gadgetoid, that’s a really helpful response.
David


#4

Hi Gadgetoid/ All,

Was following up your suggestion on the adafruit 5v PSU. I’m in UK and this product doesn’t seem to be stocked by Pimoroni. Reluctant to have this shipped all the way from states (and i need 3). Can anybody suggest alternatives easily available in UK?

DP


#5

I’d give this a go:

http://makersify.com/products/adafruit-5v-10a-switching-power-supply

Plus:

And a few of:

This is about as makeshift a power distribution setup as you can get, and I’m not qualified to know whether it will just melt :D

But it’s tidy!


#6

Thanks so much for this!

David