Tube Depot has KT150's for 144.95. They are Tung Sol, so not sure if they are good enough for your amp.
Back in the day, we used 6550's, which were pretty good tubes, and KT88's as well. Tube Depot as those as well.
Cheers!
Why are people paying these stupid tube prices?
Just ordered a set of 4 KT150 power tubes for $139.00 each yes it is more than a year ago but $350.00 each $1400.00 for a quad.
Simply crazy dude.
www.tubestore.com