I have re-tubed my TT presignature with all ne matched el84 valves and need to set bias. Thesere are two trimmers inside.
I can only find information on the signature model and wonder if anyone has a service sheet or any information on how to set the bias properly?
I can only find information on the signature model and wonder if anyone has a service sheet or any information on how to set the bias properly?
Have you seen the recent thread on the Unysis on HifiWigwam. It includes a schematic. 'Signature' version but I don't think the basic design changed much. If you're asking what was the original operating point, I seem to remember it was rather 'hot', but you can try a range of ballpark values and see what you prefer.
Thanks STE Factory setting was 25mV as per the QC label inside. Equates to a negative bias of approx -13v . All good at present.