Gallien Krueger 800RB Hi Channel Problem
G.K. 800RB .Varied volume and lots of distortion on hi channel.. Line out to another amp ok. Cleaned hi channel pot, still distorted.
Signal to effects return, distortion.. Low side works great. Distortion with biamp in or out. Thanks
G.K. 800RB .Varied volume and lots of distortion on hi channel.. Line out to another amp ok. Cleaned hi channel pot, still distorted.
Signal to effects return, distortion.. Low side works great. Distortion with biamp in or out. Thanks
By channel you mean the lower power power amp, the 100 watt, usually used for higher freq cab? I assume so.
If you do not have the schematic, call GK and get it. There are more than one version of this amp, though all similar. Can you identify which you have? Any board numbers or date ID on the boards would help.
But in general:
Scope the output, what does the distortion look like? Half waveform missing? Uneven clipping? Even clipping? Crossover distortion? Other?
Is there DC offset more than a quarter of a volt?
The +/-60 and +/-80v power rails come from different supplies, not dropping resistors, so verify both rails are getting to that amp circuit.
The power amp schematic has some DC voltages scattered around it, how close are yours?
If you do not have the schematic, call GK and get it. There are more than one version of this amp, though all similar. Can you identify which you have? Any board numbers or date ID on the boards would help.
But in general:
Scope the output, what does the distortion look like? Half waveform missing? Uneven clipping? Even clipping? Crossover distortion? Other?
Is there DC offset more than a quarter of a volt?
The +/-60 and +/-80v power rails come from different supplies, not dropping resistors, so verify both rails are getting to that amp circuit.
The power amp schematic has some DC voltages scattered around it, how close are yours?
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