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New tubes in Rogue M-180 Monoblocks

I understand the M-180s now ship with the KT-120 power tubes, instead of the KT-80. You can also simply replace the KT-80 with the KT-120 if you already own these amps. I'm curious whether anyone has done it and what their impressions are as far as the difference in sound. Is the over $300 upgrade worth it?
actusreus
actusreus OP
733 posts
 
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.
roscoeiii's avatar
roscoeiii
1,155 posts
 
As I mentioned, the bias meter on the Stereo 90 reads 5mA low. As is stated in the Stereo 90 manual. I don't know about the other Rogue models. But for the Stereo 90, when the meter reads 35mA, the actual value is 40mA. And an actual value of 40mA is also what I was recommended by Rogue.

Other people with KT120 tubes have recommended a higher bias than this.
dhcod
706 posts
 
I have biased my Rogue Atlas as high as 55. It's heaven but hot and I don't suspect the tubes will last more than a year or so but for me it's totally worth it.
roscoeiii's avatar
roscoeiii
1,155 posts
 
Dhcod,

Are these tubes KT120s?
actusreus OP
733 posts
 
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?
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