Voltage Selector Marshall 2204

[BesaMoogie]

Hi,
I have a Marshall JCM800 2204 that runs on a low plate voltage of 360V. The voltage selector is set at 240V, my wall voltage is approx. 230V (EU). Is there anything else to consider when setting the voltage selector at 220V to get a higher plate voltage other than rebiasing the output tubes?
Thanks!

 

[Chubbs]

Your heater voltage is going to probably be too high and not sound great. And depending on your dropping resistors everything in the preamp will be over the “ideal” voltages. My guess is things are going to sound quite harsh. Unless you go the route of a step up transformer for the powertubes.

 

[SpiderWars]

Hi,
I have a Marshall JCM800 2204 that runs on a low plate voltage of 360V. The voltage selector is set at 240V, my wall voltage is approx. 230V (EU). Is there anything else to consider when setting the voltage selector at 220V to get a higher plate voltage other than rebiasing the output tubes?
Thanks!

Since you seem to be comfortable with measuring voltages I think its worth a shot. Just get everything all set up to measure beforehand and be prepared to shut down. 360vdc is pretty low but many of the 50W Marshalls had really low voltages like that. Your B+ rail will be IMO at better voltages, that's not an issue just rebias. But check your heaters like @Chubbs said.

 

[BesaMoogie]

Thanks for the advice. I measured the heater voltage. It was 6.02 VAC at the 240V setting and 6.57 VAC at the 220V setting. PV went up from 360V to 390V.