I was done chasing guitars and amps. I have four(4) cores and the 50 watt HXDA, 100 watt Lonestar heads and that was that...BUT when this showed up on the usual site(R) for an incredible price, it had to be bought. I'd seen and heard Grissom play thru this rig, so I didn't need to audition it either because I knew what it sounded like, pretty amazing. (unlike a lot of gear endorsers that hawk one thing and play something else all together). All power tubes are the 7189/6P14P-EV and the same with the preamp tubes, JJ brand, 3xecc83, 1xecc81 as listed in the owners manual. Checked the bias: left side test points: 36.5, 39.5; right side test points: 39.0, 38.0. Manual says: +/- 35. "Tubes can be mismatched somewhat, but it is recommended to not vary more than 5 millivolts or so for tonal reasons" per the manual. Dead mint, not a fingerprint on it.