RE-BIASING FOR LOW VOLTAGE

[9VOLT1967]

I have a MV100 that I built and am quite happy the the amplifier. I am experimenting with the low voltage transformer tap. I disconnected the high voltage tap that was sending around 512V for the B+ voltage. I reconnected the low voltage tap and had 404V B+. I have EL-34's in the amp so I calculated 17.5 / 404V = .043MV for the new bias setting. The bias spool allows me only .020MV for the bias setting. What do I have to change to get my bias to the desired setting? Thanks in advance.

[9VOLT1967]

I will answer my own question here! Replaced the 27K bias resistor to a 39K and re-biased to new voltage requirement.
V5-40.7 V6-40.2 V7-42.5 V8-41.1

I found a thread where it said, "more current-more resistance"--less current-less resistance". It was recommended to parallel the the resistor, but I happen to have a 1WCF 39K handy so I swapped it out and I still have 25% rotatation left on my bias spool. Thanks!

[RINCON1970]

I was wondering how does it sound at 400 v vs 500 v. I was also looking into running it on a 500-standby 400v set up similar to the 12000.

[9VOLT1967]

I personally like the sound of the low voltage better. It seems to have a warmer breakup of sound. I would have ran the multi-switch, but I have rocker type switches on my amp. I had an amp in the past with the low / high power selector and I always used low power.