2204 Bias Splitter resistors 220k vs 150k

[john l]

My understanding is that 150ks will accommodate both 6550s and EL34 types so I was thinking of swapping the 220ks for 150ks and adding an internal swtich that will alter the range resistor so I can use either type. That said, marshall used 220ks there for a reason and I wondering if Ill be missing anything sonically when using EL34s with the 150ks.

[statorvane]

I did this on my son's JCM800 clone a few years back, replaced the 220K w/ 150K. Got this idea from the Tone Lizard http://www.tone-lizard.com/Ultimate_JCM800.htm Marshall probably used what Leo did with the 5F6-A and kept them when they switched to EL34s. They replaced them for the 6550s issued in the States.

I don't play his amp that much, but I really didn't notice a difference between values. My son rarely cranks it.