DC offset with Electrocompaniet AWII

[legarem]

Hello

Dc offset can't be nulled on one side of an Electrocompaniet AWII. If I load the input with a 100K resistor, I can do it. I thought replacing R5 with 200 ohms to have more range with the pot. Here is the front end schematic. There was a service bulletin with upgrades that have been done. C1 and R4 are now replaced with a jumper. C2 is replaced with 1K resistor. Thanks

 

[audiofan]

Can we seemore of the circuit ???

 

[legarem]

Here it is.

 

[knutn]

R4 must be equal to R1 and can not be removed from the circuit.

 

[legarem]

This is what I suspected. Here is the service bulletin which contains errors. Thanks

 

[legarem]

I used a 22K for R4 and it's worse.

 

[knutn]

C1 and C2 can not be removed (if using in balanced mode).