I found this link very useful:
it nails the description of my problem:
"Microphonic problems usually appear in the form of a ringing or high pitched squealing that gets worse as the gain or volume is increased thus are more noticeable in the higher gain Lead modes."
Also, I just suffered an extremely irrepressible GAS attack and just bought a 7025 HIGHGRADE TAD Premium Selected for V1, and a 12AX7A/ECC83 TAD Premium Selected for V2 :) just for experimenting
The EH that are coming won't bother anyhow.
Your one-stop shop for troubleshooting noise, hiss and related issues with this High-Gain Monster!