V4 PCB component repair/updating

[beedoola]

In the ampeg, I thought the cooler bias happened to sound best--cooler bias like you have offered HUGE lows, and no mid-range mush. Big, loud, clean, but not harsh. I put back the stock value resistor, and have left it ever since. Note: with blackface style fenders and 6L6GCs, , I tend to like the bias closer to 50- 70% to get more mids I suppose.

I personally agree with this, too. I have a set of JJ 7027A's. These are definitely 30 watt tubes...unlike the original American made 7027A's which were actually 35 watt tubes. With a 528vdc at the plates, the bias on my VT-22 is set at 34ma's. It's a "cool" setting that to me it's win-win situation because the amp sounds right to me, and promotes longevity for the tubes.
BTW, here's my Adjustable Bias Mod:




I should have plenty of range with this setup - should I go insane and invest in a set of some NOS 7027A's...if they even exist! Oh yeah...there's not much of a margin for a shaky screwdriver, so I always use a insulated one!

Which resistor was replaced for the mod and what are the specs of the trim pot? - voltage tolerance?