I have a problem with a simms watt. Its a 100 watt, but has been fitted with KT77's. There are also a few differences to the schematic, there is no bias tap on the transformer but instead is taken from one of the HT's via a resistor then just one one pot with reversed diode then split via two resistors then to the power valves via resistors. The amp arrived to me with the pot maxed out giving -80v, although the schematics suggest -50v. Is this normal or has this been done for the kt77's? AT the moment I'm getting a very low thin sounding output, is this a result of the -ve bias being too high? What is the effect of the -ve bias being set wrongly?
AS you've probably guessed I'm new to all this though have worked on loads of different ss gear so please be patient.
Cheers Just