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Crossover distortion puzzle.

12/11/2004 2:50 PM
SteveG	Crossover distortion puzzle. Hi I have a 2xEL84 amp that closely resembles a Matchless Spitfire, but with a stepped attenuator post PI MV. The sound is fine, except at very high input signal/gain levels, where there is a brittleness to the distortion, and an unmusically related note that accompanies the 'normal' sound of the amp. Scoping the output revealed a huge amount of crossover distortion which disappears at lower volume levels. Anodes are at 312v, cathode resistor is 120R. Oh, and when one side of the PI output is grounded, all problems disappear, and it becomes the loudest, best sounding 5 Watter I've ever heard! Anyone have any thoughts? -Steve

12/11/2004 2:50 PM

SteveG

Crossover distortion puzzle.

Hi

I have a 2xEL84 amp that closely resembles a Matchless Spitfire, but with a stepped attenuator post PI MV.

The sound is fine, except at very high input signal/gain levels, where there is a brittleness to the distortion, and an unmusically related note that accompanies the 'normal' sound of the amp.

Scoping the output revealed a huge amount of crossover distortion which disappears at lower volume levels.

Anodes are at 312v, cathode resistor is 120R.

Oh, and when one side of the PI output is grounded, all problems disappear, and it becomes the loudest, best sounding 5 Watter I've ever heard!

Anyone have any thoughts?

-Steve

Replies:

Dr. Photon check the bypassing of the cathode ... -- 12/13/2004 12:12 AM
Dirty George It sounds like blocking distortion ... -- 12/13/2004 2:23 PM