AC15H1TV question

[terrapin]

I absolutely LOVE this amp, but would like to understand why the EF86 channel is virtually absent of "hum" with both single coils and humbuckers while the Top Boost channel has some "hum" (although minimal) with both single coils and the humbuckers?

Unfortunately of late I mostly play in my music room at home so the amp is set at 7.5 wats and in triode mode.

Is it inherent in the circuitry? Or, is it inherent in the "old" electricity in my little beach house? Or WHAT. It is minimal, but it is there!

I am running good NOS tubes throughout the amp except for the 12AX7's which are Russian made Groove Tubes.

What do you think?

Thanks,
Russ