Looking for a good clipping circuit for 1000 watt audio amp.

Huh? Why would you want to do that?

Wouldn't it make a great deal more sense to clip at one of your low-level audio stages, where it is relatively easy to implement a variable clipping level adjustment, such as those commonly used in radio and TV broadcasting applications.

Perhaps I'm missing something.

Harry C.

Yes Harry, you are missing something. You'd never want to clip the signal source, how would you deliver clean power to an amp otherwise?!?

First off to the OP, you can't implement such 'protection', it isn't that bad when an amplifier clips. The top and bottom of the waveform literally get clipped, and until you get into gross clipping that is audible, the setbacks are not noticable.

You want PEAK transients to get through, and often enough, these peak transients clip the power supply.

A clipping circuit is usually a indicator (LED) telling you that the amplifier is clipping. Protection on the output is another story. You don't want it to unlatch the outputs like that, if there is hardly any protection, your amp may not even have open load protection!?!?

Put the amp on a circuit capable of running the amp at full power, apply a test signal

1khz lets say, then turn up the gain and observe the output on a scope while it is connected to a resistor load capable of dissapating the power. Once you see the waveform clip, you can set this as a reference lets say to a LED VU meter (ie: Dorrough Loudness Monitor Type 40-A).

Or you can monitor the voltage on the output, and then design a circuit to light a LED when the AC V gets to that point, however, this won't be entirely accurate.

check out

and see how a professional amplifier mutes the input when a total short across the output occurs, and how it actually eliminates clipping without loosing the peak transients from coming through.

hope that helps.

source, how

Right, me bad! I used the term "clipping" rather than the proper term "limiting".

We do this in broadcasting simply because if you don't you will overmodulate and splatter crap all over the airwave spectrum, and in response the FCC will hit you with a stiff fine.

In audio work it really doesn't make much difference, because when the amplifier and speakers are driven to their clipping or cut-off limits and distortion artifacts result occur, today's listners don't even notice it, since it's so much a part of today's sounds!

I really don't look forward to the days when audio amplifier designers begin to imprelement the audio signal processing utilities that have been standard equipment in the radio broadcasters repotoire for the past 30 years, since that would invite a "wall of sound" that would abolutely negate any posibility of a relaxing drink and seductive conversation with an attractive female, at least at most places I know. :-)

The normal equipment line up at the transmitter of a typical rock station consists of (brand name or generic equivalent) a GE "Stay Level" amplifier feeding into an RCA Peak Limiter/Clipper amp, likely followed by a Gates Absolute Clipper. This lineup with keep you at between 92 and 99% modulation all of the time while safe from the FCC. Of course your audio signal sounds like crap, but today who cares in view of the crap that it is being receive in! Right?

Harry C.

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Thanks for the information, currently I have no speaker protection in my amps at all. They are very stable at the moment but I figure I'm asking for trouble. I probably asked the wrong question, I really need some sort of speaker protection that I can easily incorporate in to my current amps. Thanks

My Bryston 3B has no protection on the output, it is a high current amplifier a true workhorse.

To eliminate problems at the output stage, you can use an outboard compressor/limiter/expander on the input.

I wouldn't put in any type of protection on the output stage of an amp, the more passive components on the output, the more chance you will hear it.

Ideally, a decent amp with a high damping factor and well damped speakers (high mechanical Q) will be able to shake off just about anything your amp sends it. AS LONG as it isn't DC!! That is a whole other type of protection, once an amp goes DC, it will literally fry everything after it.

Being in the professional audio industry for so long, I've only blown one woofer (18") and it was because it was severely fatigued (like I am at the moment!).

What type of amps do you have?