Yesterday I started up the DIY Tube ST70, I began using some old Sovtek EL34 tubes..everything went fine, bias was established and steady with no trouble. Disconnected the amp from dummy loads etc and put it into my system. Right channel output way too small, also may have been some tonal differences. Turned of the amp pulled the Sovtek tubes and installed a practically new set of EH 6CA7's, was able to set the bias with no problems. Re installed the amp in the system, turned it on and there was no change to right channel output still way too weak.
This amp has 2 Dynaco cloth lead output transformers that were obtained at the bay. I am wondering if the symptoms I have described are a bad output transformer. Or could the problem be on the driver boards..
Thanks