[bikerhifinut]

Thanks guys.
I'll scope the amps and see if they are oscillating at HF, seems odd though that both are doing it and exhibiting identical effects on the same phase. and not on the other.
However it cant do any harm to try 100pF caps from grid to cathode. Would ceramics do or do I need film caps?

I can also try 1k screen grid stoppers, nothing to lose by that. And maybe drop the grid leaks to 470k, I don't need so much gain.

I think i am running the EL34's way too hard though and in the absence of an alternative set of valves I can only try the above solutions. NOS or even used Mullards are so expensive that they never even figured in my plans. I dont believe all new manufacture valves are bad, just theres some out there not so good.

By the way I only spotted the hot spots because I had the amps on while the room was dark. In daylight or under normal artificial light I cant see any problem even close up to the valve bottles.

Onwards and upwards as they say.