178.223.3.115
This Post Has Been Edited by the Author
In Reply to: RE: FWIW the GRAAF GM 200 and the GM 20 are quite different. posted by Lew on February 01, 2012 at 13:18:26
Hi Lew !
From my attached link you can download more accurate schematic of Graff GM 20 power Amp .
There is obviously that input differencial stage (6922 tube) is AC bootstraped to output Circlotron power bridge , formed around of two 6c33c-b power tube .
Input differencial stage (6922 tube) DC B+ feed is sourced from the same output power two floating B1/2+ power supply .
Two separate DC bipolar supply sources is designed to be B+ source for two drivers EF184 tubes (+297V ), differencialy conected .
And - 250 V source is designed to be the B- supply for both differencial input and driver stage , and in the same time is source for negative B- Bias supply for output Circlotron power stage .
It is my personal opinion that model Graff GM200 is designed in simmilar way , more or less .
Best Regards !
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Enlightened Evolution-Astral Projection
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