Yes indeed - not much around on these amps, strangely. I'm just about to replace the vales on one side of mine (9100). But I'm keeping it stock so 5881/6L6. What was the bias before you changed it or what do you recommend?
I don’t remember what the bias was but, I always believe as using the plate voltage and the bias at 70%. I have a few videos explaining that. You also have to balance the 12At7
@@conjering I'll check your other vids - never done this before. I haven't got a tube base adaptor for the smaller valves, why would I need to adjust those if they are not being changed? I'll let you know how I get on anyway!
Are there any screen resistors that can be installed to this amp that can handle both 5881 and el34 ? that way if you want to go back to either tube type there's no need to mod again
The simple answer is no. Marshall told me the output transformers on this amp is meant for EL34’s so changing the screen resistors to 1k will be the correct way
Awesome video! Thanks!
The 5881 heater filament draws 0.9A and the EL34 draws 1.5A. Are you sure the power transformer can handle the increased heater current?
Yes, I thought the same thing, but Marshall tech in England said it was good to go
Yes indeed - not much around on these amps, strangely.
I'm just about to replace the vales on one side of mine (9100). But I'm keeping it stock so 5881/6L6. What was the bias before you changed it or what do you recommend?
I don’t remember what the bias was but, I always believe as using the plate voltage and the bias at 70%. I have a few videos explaining that. You also have to balance the 12At7
@@conjering I'll check your other vids - never done this before. I haven't got a tube base adaptor for the smaller valves, why would I need to adjust those if they are not being changed? I'll let you know how I get on anyway!
Are there any screen resistors that can be installed to this amp that can handle both 5881 and el34 ? that way if you want to go back to either tube type there's no need to mod again
The simple answer is no. Marshall told me the output transformers on this amp is meant for EL34’s so changing the screen resistors to 1k will be the correct way