this post was submitted on 25 Oct 2023
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How to Dimension a Power Supply for an Audio Amplifier ? (discuss.tchncs.de)
submitted 1 year ago by megrania@discuss.tchncs.de to c/askelectronics@discuss.tchncs.de
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Hi,

I recently bought a few pre-made amplifier modules for an 8-channel amplifier project (for a sound installation).

The amp is based on the TDA7294 chip and is rated 85W nominal. Now I'm looking for a power supply, but I'm a bit lost (this isn't really my strongest field, to put it mildly).

Do I just need to add up the output power, 8*85W = 680W, or could I get away with using something smaller, like a 300W or 300VA?

Also, the seller said that you need to use CV power supplies, CC won't work and kill the circuit. Does that mean a switching supply can't be used?

It looks like the module has a rectifier and smoothing caps integrated, so I could potentially just use a transformer, right?

Best, N

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[โ€“] ignotum@lemmy.world 2 points 1 year ago (1 children)

Disclaimer: not at all an expert on this, this is just my thoughts based on what i've heard, please correct me if i'm wrong

  • Normal power supplies are CV, so you don't have to worry too much about that, CC supplies are a bit more niche

  • If you want to be able to run the amps at full power, you'll have to add up all their rated powers and find a psu that is rated for that, it could also be wise to go with one slightly larger as well, as power supplies tend to get a bit noisy when they're close to the limit (the voltage they give out gets noisy that is) which reduces the audio quality

  • what are the input for the amps? You say they have built in rectifiers and everything? Can they be aupplied by mains directly? What is the max input voltage?

[โ€“] megrania@discuss.tchncs.de 1 points 1 year ago

Hmm they are rated for 12V to 32V, and the seller recommends using a toroidal transformer to achieve the symmetric power it needs.