Been a while since I posted here (2006
)I built a JTM45 from parts i sourced myself. Used the build guide from Metropoulos which was a fantastic help.
Move forward to this week, one of my original valve arts KT66's died, lasted 18 years so cant complain about that. I put a pair of gold lion KT66's in there last night. Tested the bias and I'm getting 92mv on both tubes. Mine didn't have a bias trim pot rather just a 47k resistor, at the time of build the bias measured around 35mv. To be honest I have not opened up the amp since building in 2006.
I have ordered a trim pot and 2 new 10uf bias capacitors as they were showing a bit of discoloration at both ends.
I'm getting 427v plate voltage. I'm not going to do anything before fitting the trim pot but was hoping I could get a few pointers where to look for the high bias voltage. I did a lot of reading and research at the time but nothing since so will have to get reacquainted with the whole workings of valve amps again.
Cheers in advance.
Simon