# Pictures of that 'clipping' we've heard so much about



## CBRworm (Sep 1, 2006)

I am getting ready to renovate an old reciever of mine (30 years old). I wanted to capture some performance parameters before and after. I will say that I have never turned this reciever up this loud before, and probably never will again. Surprinsingly during my testing it didn't really get any hotter than it does at normal levels (it's always very hot). I ran it near clipping with music and sines for over an hour. Also surprising that nothing broke - but that was kind of my point, if something was going to break I wanted to find it now before I go inside. 

I had it connected to a JL 12W6V2, dual 4 ohm in a 1cf sealed box - 1 VC connected to each channel - the reciever is rated to be 4 ohm stable, although it doesn't say for how long.

I drove it to clipping with music, which interestingly I could just barely hear although on the scope it looks like I should have been able to hear it quite well. Along with the woofer I had a resistor and cap and tweeter connected to one set of leads thinking that I would hear the tweeter distort. I also had the alpine tweeter protector light bulb in line with the tweeter so I wouldn't cook my last alpine XT tweeter.

After that I disconnected the tweeter and drove it with a 40hz sine wave. The clipping was very visible there - still not really audible.

I did a good bit of other testing and the results were so good that I am tempted to not open it up. I figured you guys would only be interested in seeing the pictures of what destroys our equipment.

So here are a couple pictures of my scope during very hard clipping during music and also with a 40hz sine wave. I expected there to be some imbalance between the + and - side, but the numbers actually came out quite good. I did a bunch of different tones, but when I got to 100hz I blew the 10 amp fuse. Luckily after replacing it everything still works. 

I know most of the technical guys have there own scopes and have seen this plenty before, but for those who don't understand it - here's a good visual reference.

At the clipping point it is putting out just about 400 watts. Obviously it is not useable, but the potential is there. But I was able to do a continuous good solid 240 watts per channel at 4 ohms well below the clipping threshold with both music and sines. 

Today it comes apart for refurb.

The first picture was some hip hop music that had a continuous bass line of about 70hz.


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## Abaddon (Aug 28, 2007)

Sweeeet... we have the same scope!

I prefer the 30 year old Phosphor based one that I have access to at work though... I find that it displays clipping in a much more realistic fashion...


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## CBRworm (Sep 1, 2006)

Yeah, I've been through a few over the years. For my use the size can't be beat. Now instead of having to take things out to the workbench, I just bring the scope to what I am working on.


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## Abaddon (Aug 28, 2007)

I picked mine up for $50 when a local engineering company went under.

I don't think it was ever used...


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## CBRworm (Sep 1, 2006)

That's awesome. I wish I could find deals like that.


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