0
\$\begingroup\$

May I just ask if Class D amplifiers are expected to stay continuously on, flat out, at full power and never have the volume reduced?!

I’ve recently obtained this:

http://www.amplifier.co.uk/images/SDV1042-600_1_ETS.pdf

...It’s my first class D amplifier project and I just expected but I could turn it down with some sort of master volume pot. Am I wrong?

If not then Where would be the best place to connect a master volume on the power amp, please?

\$\endgroup\$
0

3 Answers 3

3
\$\begingroup\$

It is not a job of the power amplifier module to do anything else that to amplify its input and drive the speakers.

Normally you would put the volume control before the input of the power amplifier.

\$\endgroup\$
1
  • \$\begingroup\$ Excellent, confirms my first instinct from a source I trust more than my own knowledge. \$\endgroup\$
    – Hearth
    Commented Apr 7, 2020 at 16:47
2
\$\begingroup\$

I just expected but I could turn it down with some sort of master volume pot. Am I wrong?

For this one, yes.

In a stereotypical amplifier the volume control is placed between the pre-amplifier or in the pre-amplifier itself.

schematic

simulate this circuit – Schematic created using CircuitLab

Figure 1. Volume control placement for a power amplifier. A logarithmic or "audio-taper" is required.

\$\endgroup\$
2
  • \$\begingroup\$ Well I’ll be... \$\endgroup\$
    – merseymale
    Commented Apr 7, 2020 at 16:50
  • \$\begingroup\$ “ You learn something new every day“ I’m used to working with valve/tube amps but the notion that a power amp is plugged into the mains and happily sits ‘unused’, as it were, not drawing current until it receives an audio input is pretty remarkable to me... we live in interesting times! Thank You so much for your insights, everyone \$\endgroup\$
    – merseymale
    Commented Apr 7, 2020 at 16:52
0
\$\begingroup\$

Disclaimer: I'm not an expert on audio, and there may be better ways to do this, and there may be a volume knob somewhere on your class-D amp to begin with, but:

I would put a potentiometer in a position to attenuate the input. If your input is a high-impedance source that wouldn't appreciate this loading, try using an op amp to buffer it before attenuating it.

\$\endgroup\$
1
  • \$\begingroup\$ P.S: there certainly isn’t any form of variable resistor on this amp’s circuit board 👍 \$\endgroup\$
    – merseymale
    Commented Apr 10, 2020 at 12:14

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service and acknowledge you have read our privacy policy.

Not the answer you're looking for? Browse other questions tagged or ask your own question.