Jumping channels on an AC30 heritage or using an A/B box?

[Dr. Tweedbucket]

I haven't tried this yet, but imagine that you could jumper the EF86 and 12AX7 channels together and blend them, right? I also was thinking of rigging up A/B switch to Y adapter to select either channel. Does anyone make a decent Y adapter?

What works the best with these amps?