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Does anyone know this setup




I have an ST70 that I built custion, years ago.... It includes an SDS70 Cap board and a PC3U. EL34's and 6922's


The board I have was without any bias options. However I found that I had removed the connections
V1 pin 8 to V2 pin 1
V6 pin 1 to V7 pin 8
and replaced the 15.6 ohm resistors on each side with 10 ohms to ground on each of the four tubes . the same as the DC balance option wiring in the PC3U instructions.

Ill assume electrically, that I should set 1.0v on the bias port up from on each side of the amp.

Why did I do this though. Im sure I had a good reason. But am I now just reading the values of one tube to set the bias in the hopes that the EL34's on each side are perfectly balanced?

Am I wrong but didnt the connection between the tubes read an average voltage drop in support of the bias when using a 15.6 ohm resistor for a reading of 1.56v


If I set the bias now to 1.0v.... what am I really reading? just the front tubes on each side.


help!

Jordan






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Topic - Does anyone know this setup - jrubin 15:41:09 08/23/15 (7)

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