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How about using a simple step-up transformer to deliver ~240v to the amp (and obviously using the amp's 245v tap)? Been doing this for quite some time with my '69 SC MKIII with no issues…in fact, the amp actually sounds "sweeter" to me @ 245v vs. the 115v setting. Would this help with this...

Thanks, Mark!

My tech and I have discussed changing the screen resistors from the stock 100R 1/2w to 1k 5w to better protect the EL34s…any reason NOT to? The DR504 schematic shows 1k, correct? Any real tone/feel difference?

Thanks, Clayton! :D My tech just replied with this: "I figured out the resistor value. Its 750R. First I tried a blacklight, no good, then a green LED and that worked! So, the values are odd. I haven't come across these values anywhere yet. 750R 10w, 6k8 2w, and 100R 5w. The more common values ...

Update: my tech is currently in the process of restoring this amp, but he has a question for the experts: "I need to know the value of the large green voltage dropping resistor (choke resistor, for lack of a better description). It's a 10w resistor, looks to me like it is common to all MK2 SC ...

Greetings...new member here! :) I recently purchased a Sound City 100 PA Mark 2 amp from a private seller in the UK. I am aware of the Dave Reeves connection with the original SC100 ("Mark 1") amps, as well as his (likely) involvement with the elusive Mark 2 models. The Hylight serial tag ...