[Diabolical Artificer]

Here's the schematics if anyone's interested and some more pics. Not shown are PSU and aux circuits.

Yesterday was spent improving the clipping indicator by putting a diode and cap on the base of Q1 as recommended by Argus in another thread. One thing that's problematic is that the amp behaves differently when testing with a sinewave say to when playing music, EG the clipping indicator behaves differently with music. It's a minor issue, one easily solved.

One other phenomenon of notes is OP power. When testing with a sinewave OP is 33v before clipping, when playing music OP rarely goes higher than a few volts, so therefore higher than a watt or so. Obviously it will go higher instantaneously on peaks, but I haven't the test gear to capture this.

This is where measuring amp performance is tricky, and the standard nomenclature deceiving, using a SPL meter might be better. Folk like to see numbers on amp specs, but I bet most don't understand what they mean. So it's understandable when subjective terminology creeps in. You can hardly put "bl**dy loud without sounding cr*p" on the amp spec sheet.

The bottom plate was a pain. Marking and drilling the air holes wasn't too hard, but deburring said holes cleanly was a nightmare. In the end I couldn't do it, so had to use a file and sandpaper thus destroying the good finish so I had to paint it.

Andy.