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. 

128x128nickrobotron

Rouge builds great gear. Matched tubes are greatly overrated if the bias is used correctly or you amplifier has a reliable auto bias. I would fix it and quit wizzing away money on matched tubes. 

While admittedly a long time ago, I recommended Rogue to a friend. He bought a new amp. Within a short time a tube blew taking out some resisters. It was still under warranty, but they would not cover it. My friend argued with the founded. I think my friend ended up paying for it to be repaired. That is not a good way to get a good reputation. But lots of egg on my face. Rogue never gets my recommendation.

Another vote for Rogue's reliability. I've owned (and still do) two of their preamps RP-7 and RP9 as well as their power amp Stereo 100 for years and have zero issues with them.  Build and sound quality is excellent.  I did have the RP7 upgraded to the RP9, sent it to Rogue for the upgrade with ~2 week TAT.  Rogue is a quality company in my experience.

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

The amp uses KT120s

Per the amp’s manual:

Using the bias tool, slowly turn the screw on the potentiometer that is adjacent
to the switch until the bias meter reads ~ 35 miliamps (mA). Turn the screw
clockwise to lower the bias and counterclockwise to raise the bias. Note that
there are two ends on the bias tool. Using the end with the recessed
screwdriver will greatly facilitate this operation.
9) Flip the switch back into the “run” position thus disengaging the tube from the
meter circuit.
10) Repeat the above steps for each of the tubes in both channels.
As it is a quick operation, the tube bias should be checked on a regular basis. Note
that the bias will change slightly on a day to day basis as the wall voltage
fluctuates. Constant biasing will wear out the bias potentiometers prematurely so
do not adjust the bias unless it is more than 4-5 mA from the correct setting.

The Op didn’t state how many approximate hours he has on the tubes, but unless they are all nearing end of "expected life" , there’s no reason to replace all since each is individually biased. That said, the bigger immediate issue for the Op based upon a google search is that new KT120’s appear to be out of stock at a number of vendors.

 
Not sure I follow this statement by the Op "So much attention went into matched tubes. How am I supposed to just replace one tube and throw out all that paid-for attention to detail? "
 
Other than selecting matched quad when ordering there's not a whole lot of attention required