Convert Marshall 100watt1959 superlead EL34 to KT88

[cluster]

I'm sure this must have been covered here at some point but I just need some confirmation.

I have 12000 series super lead that I build way back based on Metro Amps dual tap PT which can deliver either 530VDC or 480VDC to the plates depending on the position of the standby switch. It has the traditional 27K bias range resistor and 220k bias feed resistors as spec'd for EL34.

My question is: can I just swap out the 27k bias range resistor to accommodate the KT88s or do I need to also swap out the 220k bias feed resistors for 150k?

The JJ KT88 data sheet says I could use 220k http://www.thetubestore.com/lib/thet...re/JJ-KT88.pdf

Can anyone comment if the 220k would work?

Thanks

[drewl]

The 220k resistors can stay although they did use 150k on some US bound amps fitted with 6550's like my '73 50watt.

If you have enough bias the 27k can also stay.

[cluster]

The 220k resistors can stay although they did use 150k on some US bound amps fitted with 6550's like my '73 50watt.

If you have enough bias the 27k can also stay.

Thank you very much. I'll give that a shot.

Joseph