Turned out to be a lovely piece of equipment. So far I've only replaced the filter caps but plan on updating the rest of the caps.
In the meantime, I'm hooked. The amp sounds simply wonderful, which is why I haven't rushed to update anything else.
Moving forward a year.
My son was using my old HK870 power amp and it is slowly dying. I found an ST-70 in pretty good shape and it will be his for the holidays.
The EL-34s (may be the originals) appear weak and will be replaced.
I am aware of the power supply issue and it will be taken care of.
I wondering what to do with the 7199 tubes. Should I use them until they die or replace them?
What seems to be the best tube to replace them with?