#1
i just put new ruby preamp tubes in my dual rectifier and a few days after i put them while i was practicing with my band, it just stopped playing. i put it on standby for a second and then turned it back on and it was fine. then, just now, i was practicing and pretty much out of nowhere the sound turned to ****. its distorted in a terrible way. im guessing its a problem with the tubes. i checked to make sure all the preamp tubes were in all the way and they were. i noticed two of the power tubes were emitting a blue glow. this means theyre going bad right? is that the problem? if not what could it be?
Jackson DK2M White
Mesa Dual Rec(2 channel)
Carvin V212
#3
Blue glow is normal, all of my tubes glow blue. When they start glowing bright red you have a problem. Maybe your bias is off?
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#4
the bias can't be off its not adjustable and its been fine the entire time i've had it. i don't think its the pick-ups either since they've not been adjusted in any way. is it possible i got a bad set of preamp tubes?
Jackson DK2M White
Mesa Dual Rec(2 channel)
Carvin V212
#5
Hmm, are all of your powertubes glowing? Double check to see if all the preamp tubes are in all the way. It is possible that you got a bad preamp tube.
I don't give a shit if you listen to me or not
#6
only two of the powertubes are glowing and the other two are just normal orange. and i check and all the preamp tubes are in good.
Jackson DK2M White
Mesa Dual Rec(2 channel)
Carvin V212
#7
If you still have the old tubes and they're in decent condition you could switch one tube at a time and see if it's one of the tubes. Otherwise it may be something wrong in the electronics.
I don't give a shit if you listen to me or not
#8
i checked all the preamp tubes and they are all fine. i don't have any old power tubes to check those with. they all look like they are glowing fine though so im not sure if thats it. the rectifier tubes also seem to be fine. is there something in the electronics that could just go bad? i took it to a show last saturday and it played fine, practiced with it sunday and it was fine, and then last night it was just terrible.
Jackson DK2M White
Mesa Dual Rec(2 channel)
Carvin V212
#9
You can test for a bad power tube by removing the inner 2 or outer 2 tubes (while the amp is off), & see if it sounds OK running on 2 tubes. If it sounds good running on just the inner 2 tubes, then sub the other 2 tubes into the inner tube sockets & see if it sounds good (this way, you can also rule out tube sockets being faulty). Then repeat with the outer 2 tube sockets if no problems show up. If you decide to run your amp w/ only 2 power tubes for any length of time (I run my SLO w/ 2 tubes all the time so I can crank it more), just decrease the impedance on the amp's output.
For example, set the amp impedance to 8 ohms if you're using a 16 ohm cab. You have to do this if you pull a pair of tubes.
Edit: After re-reading your last post, I'd find it hard to believe that a tube would be such an intermittent problem. Possibly loose pin sockets where the tubes seat?? If the problem persists, you should probably have a tech look at it.
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Last edited by riffhog at Feb 6, 2008,
#10
also like, the notes just decay away, like there is a decrease in sustain. it sounds similar to a noise suppressor that is turned up too much and cuts off the notes.
Jackson DK2M White
Mesa Dual Rec(2 channel)
Carvin V212
#11
I'm pretty sure that blue glow is a glow between electrodes caused by ionized gas and is harmless. I could be wrong though.
#12
alright so now i think its the entire red channel. i switched the channel cloning over to the orange modern high gain and it sounds perfectly fine. can you guys tell me about how much it would cost to fix?
Jackson DK2M White
Mesa Dual Rec(2 channel)
Carvin V212