New tubes in Rogue M-180 Monoblocks

Roscoe,
I'm not sure what's going on with your amp, but Mark was perfectly clear that you should bias the KT-120s at 40 mA in the M-180 monoblocks, and that's what the meter should read. The M-180 manual says nothing about the meter being off, which frankly does not make sense.

Indeed, I meant KT-90, not KT-80. Thanks for the correction, Mechans.

I understand the only "modification" necessary is swapping the top plate in the Cronus amp as the tube holes are not big enough to accommodate the KT-120. I'm not sure whether other Rogue integrated amps would work with this tube. However, the M-180 monoblocks already came with holes big enough so that it's as simple as swapping the tubes. No circuit modifications are needed.

Daverz,

Are you sure about the biasing? I was told by both Mark and Nick at Rogue the KT-120 should be biased at 40 mA, just like the KT-90. Are we talking the M-180 monoblocks or the Cronus integrated amp? The Cronus is to be biased at 35 mA, but the M-180 at 40 mA.

Daverz,
I emailed Mark yesterday to clarify this. He'll probably respond sometime next week since it's a holiday weekend. I'm relatively new to tubes so I'm not sure how to determine correct bias other than knowing when it's quite off; the sound just isn't right. I've searched some of the old threads regarding biasing, but didn't find much general information on the subject applicable to all equipment. Essentially, the advice is to adhere to the manufacturer's instructions, which certainly makes sense.

In the meantime, how do you like the sound at 35 mA? Did you have them biased at 40 mA long enough to make a comparison?

I got a confirmation from Rogue that the KT-120 should be biased at 40 mA in the bigger Rogue amps, not 35 mA.

Since I don't know that much about tubes in general, I have to ask: what sonic benefits are to be gained from biasing tubes higher than the recommended setting?