Oversized toroid

[1202_ProgramAlarm]

The LM3875 and LM3886 share a lot of features and quirks. The LM4780 is basically two LM3886 in one package. So for OP's questions about the optimal supply voltage, I suggest reading here: https://neurochrome.com/pages/output-power


I have a small stash of LM3886T/NOPB that I'm selling as an off-the-menu item with my boards. Max one per LM3886DR or MOD86 board. I'll get you hooked up.

Note that the difference in build cost for a Modulus-86 vs LM3886DR adds up to maybe 10% of the total build budget once the power supply, chassis, connectors, etc. are factored in but the Modulus-86 provides vastly better performance due to its built-in error correction circuitry.

Tom

I've already got some parts ordered for the audiosector build, though I'm sure it won't be my last amplifier project! 😉

I'm interested in hearing how this error correction works, I'm only familiar with that in digital communications. Can you share anything there?

 

[PRR]

I'm interested in hearing how this error correction works, I'm only familiar with that in digital communications.

Very different. Start here:
https://www.google.com/search?q=error+correction+malcolm+hawksford
Malcolm may not be the first on this idea, and you may find other gurus you like better, but he has published extensively so is a start-point.

 

[tomchr]

I'm interested in hearing how this error correction works, I'm only familiar with that in digital communications. Can you share anything there?

It's a composite amplifier. You can think of it as two amplifiers in series with a global feedback loop. This results in extremely high loop gain (and resulting stability challenges). Basically you get the power of the power amp with the precision of the controlling opamp. It's an old trick actually. The extremely high loop gain reduces distortion to immeasurable levels and also results in excellent PSRR (and many other nice things).

Tom