Best Audio Clipping Ind Circuit

I am driving a 12W audio amp module from a PC soundcard and would like to fit an _adjustable_ clipping indicator.

Would like to keep the circuit as simple as possible. Not a hi-fi application. It's just because the PA speaker is in another room and I cannot hear if distortion occurs.

What are the pro's and cons of the circuits below? Any other suggestions?

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The next is simple, but not adjustable, and would need to be modified for a 12VDC supply.

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(fourth diagram down)

Thnak you for any advice.

Paul Kent

Reply to
Paul kent
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Use a compressor instead, like...

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I use one to level everything out of my Roku Soundbridge before it goes to my sound system... since streaming feeds on the Internet are so variable in amplitude. ...Jim Thompson

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| James E.Thompson, CTO                            |    mens     |
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Reply to
Jim Thompson

Nice, but I want a small circuit I can build into a device. Sorry, if that wasn't clear.

Paul Kent

Reply to
Paul kent

I don't like any of the circuits. I'd be more inclined to characterize the amp and set up a circuit to go off when the clipping limit of either rail is reached.

As an aside, you might want to read up on full power bandwidth. If you had access to AP gear, you can set a distortion target level and it would sweep the frequency, adjusting the audio level to maintain the target distortion. My point is clipping is very gross distortion. Amplifiers go south before reaching the clipping limits.

Reply to
miso

This isn't too bad, but it will vary in sensitivity with the battery voltage. A low power regulator driving R2 and R4 will fix that.

There's a very long list of things wrong with that one.

Same link.

Since this isn't hi-fi, feed the speaker output to a 47 Ohm resistor, then to a bridged rectifier, then to a string of cheap LEDs. The more LEDs in series, the higher the illumination threshold. It will probably be around 8 red, 6 green, or 4 blue/white. 12W RMS into 8 Ohms is the typical quoted output of a bridged amplifier running on 14.4V.

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Reply to
Kevin McMurtrie

I've seen amps with a distortion indicator, basically input compared to a scaled version of output exceeding a limit

-Lasse

Reply to
langwadt

Sorry, it should have been this:

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Fourth circuit down on the page.

Any further comments?

Paul Kent

Reply to
Paul kent

Not bad. A 4.7V zener diode may be wrong for a 12W amp. An adjustable voltage divider may be better.

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Reply to
Kevin McMurtrie

I had long forgotten a circuit I did decades ago to do exactly this. I've just written it up and added it to 4QD TEC:

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Speaker powered Peak Program Indicator

Enjoy!

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Richard Torrens (News)

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I always thought a good way would be to compare the feedback and the input signals. As long as the amp is not clipping, those 2 signals will be virtually identical. When the amp clips the input will exceed the feedback. This will always be true regardless of power supply droops. The two circuits looked like threshold detectors which have no relationship to possible clipping and wouldn't track power supply voltages.

G=B2

Reply to
Glenn Gundlach

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That scheme sounds good, though it will only see low frequency clipping due to delay in the amplifier.

Reply to
miso

Do you get a long enough optical pulse out of the LED to "see" the clipping, or should you throw a small capacitor somewhere in the circuit?

Reply to
Ralph Barone

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