My Moscode again: What is the bias current?

[powerdoc]

One of the Moscode modifying labs commented that a wavering dc offset would not be abnormal so I'll turn my efforts to the bias of the mosfets. Right now the 60 v rail is +/- 120 ma on each channel; this seems low. Is there a correct current standard for this amp?

 

[esgigt]

I understand you own a MOSCODE 300, right? So do I, btw...

The bias current should be in that order, but I always understood that it is not very practical setting it. You could try Kaye Audio Inc: Repairs and Upgrades of Fine Tube Electronics by George Kaye for more info on the amp..

Cheers,
Edwin

 

[powerdoc]

I don't think setting it is an issue; there is a pot for that. Have had a hard time getting Kaye to answer a call or email; I think he may have modded this unit some years ago.

 

[vilfort]

Bias for the MOSFETs are around 140mA to 150mA per pair. So setting the current for the MOSCODE 300 is 280mA to 300mA. I have two of them. And that works. Then set the offset to +/- 10mV across the output (it will drift). Good luck.

D.