Can't bias 6L6 low enough in ST-70 with Dynakitparts bias mod.

I just installed the Dynakitparts bias/balance control kit in my ST-70. I am using 6L6GC tubes. I can balance them OK but can only bias down to .7 or .8 volts as measured in the octal socket. Do I need to change the bias resistors for these tubes?

-Mark

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Thanks. I'll give it a shot.

Better but still too high. I have to drop the main voltage down to 100V to get .38V bias. I guess it's time to remove the bottom and check voltages. I have an assembly manual but I was hoping this was an easy mod.
Oh well, I guess that's why this hobby is interesting - troubleshooting.

I replaced the selenium rectifier with a diode and found on another post that I should reduce the two 10K resistors to 5K. I did so then put the 5AR4 back in. I can now get the bias down to 45ma at 115V main voltage. If a little's good, a lot's better so I paralleled another pair of 5K's in. One side will go as low as 32ma but the other side won't go lower than 42ma. I think it has more to do with the tubes now since the bias supply is the same for both sides. So for my sound test I guess I will bias both sides to 42ma.
 
I was hoping to use my supply of 6L6GC's but I may end up buying a quad of EL34's.

Update. Connected a pre and speakers. Sounded OK. Checked bias and balance again after things had warmed up. Tweaked the balance a bit. Bias current now reading 32ma. Lots of adjustment now. Moved up to 40ma. Sounds good. Still need to replace the can cap.

I found lots of info here, just had to modify me search a little.