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How to Dimension a Power Supply for an Audio Amplifier ? (discuss.tchncs.de)

submitted 1 year ago by [email protected] to c/[email protected]

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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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[–] [email protected] 3 points 1 year ago* (last edited 1 year ago) (1 children)

When I look around then this amp, taking your statement with the rectifier, needs symetrical AC supply as an input.

For a mono amp the transformer would be 120W / 2x25V per amp. You need more because of the loss the amp includes

Depending on your setup and build maybe several transformers would be better. Or you add all up to 960W trafo.

[–] [email protected] 1 points 1 year ago

The idea is to have an 8-channel power amplifier in one box ...

I still have to source the right trafo, but one large one would be both lighter and cheaper (new) than, say 4 small ones. An argument to use multiple would potentially be that peaks on individual channels might have less impact on the other channels. Still working on it ...