Check your plate voltage. Is it autobias? if not, confirm your bias current by calculating the plate dissipation with P=IV,
Jerry
Rogue Audio. Reliability issues? Anyone?
I recently have been loving an Atlas Magnum power amplifier. I had a tube go bad, a fuse blow, and now red-plating. All of this could be related. But I am trying to decide if I want to pay shipping both ways ($90 each way), pay Rogue’s $175 bench fee (minimum) and then spend ungodly amounts on tubes that are hard to find.
I have friends, two to be exact, inform me that Rogue is notorious for this crap and their amplifiers are money pits. Is this normal tube stuff? Should I go for it or cut my losses and buy something else. I really love the way it sounds amd I really want to love Rogue.
Showing 3 responses by carlsbad2
@nickrobotron matched tubes is of greatly exaggerated value. Especially if your amp has good bias control. Now you're having trouble with bias (is my guess). This is why I greatly prefer manual bias control. So don't even consider paying for a matched set until you get everything back under control. Your amp will sound fine. Finally, if you are using new production tubes they will be very close to the same. Unmatched NOS tubes that may have even been manufactured in different plants and diferent years can have much more variance. Jerry |
So a post above says they have manual bias. turn the bias down by 10 mA and that should help a lot. If it is a KT88 then maxx plate dissipation is 40 watts. I'd run it at 30 watts and if having problems, I'd use 25 for a while. You need to know your plate voltage. It is pin 3. Either measure it or find a reference for your amp (this is amplifier specific, not tube specific, don't use plate voltage max off the tube data sheet). Then calculate your bias: 25= Voltage x current so bias current = 25/voltage. Jerry |