Preamp/Power tube ?

[LerxstLee]

Glad to be a new MarkV owner and glad to be back using Mesa . I am really happy with this amp. I have had it
five days and know I have barely touched it's abilities. So far so good but I do have a question as I am concerned
about an " issue " , please keep in mind my dealer is two hours each way so I would love to get this resolved without
bringing it back. I know it's covered under warranty but I really don't want to make another four hour plus trip if I can avoid it,
esp. if it is just a tube I could replace.
I was tuning with the mute on, and noticed I could hear the notes coming from the head , not a bleed through the
speakers , it is like a rattling sound of the note from the back of the amp, it is the head version.
It happens on all channels while muted. If I lower the master volume and or gain it stops. The louder I turn it up
the louder the sound from the amp head , while on mute.After listening a bit I think it is mixed in with the sound
while playing. Not a huge rattle , but more like a ringing of the note or chord in the background that you have to listen for.
Before I go digging in trying to figure out what tube/tubes it might be , would someone have a thought where I should start ?
Perhaps someone has ran into this issue and knows the answer.
I am thinking it's a power tube as I can hear it while the mute it on. My next thought would be the P.I. tube if it
is not the power tubes as it is on all channels.
Thanks in advance for you thoughts.
/cheers

 

[xyrium]

Congrats on the new rig!

Have you tried tapping on the power and preamp tubes (where possible) to determine if any are microphonic? That might rule out a tube issue. Here's a solid video from MB on some very basic amp troubleshooting:

http://www.youtube.com/watch?v=wSl-l9aWDHw

 

[LerxstLee]

Thanks for the message. Yes I could tell it was coming from one of the "outside" power tubes.
Really mechanically noisy. I went back to the dealer , they installed a new Pair of outside tubes
and it was fine. Later that night the two middle ones started doing the same thing. Along with
some squealing noise that was not a problem before. I know it was just another set of tubes and
perhaps a preamp tube causing the squealing. It was at that point I took the amp back to the store again
and returned it for a refund. The last thing I wanted to do. I know I would eventually retube this amp with
some NOS tubes but I was concerned at this point about long term reliability and just decided that I am done dealing with problems in
a new amp that has not even been gigged yet with less than 6 hours of play time on it. I really loved the way it sounded along with the vast array of sounds I was just starting to discover.
Now back to the drawing board to find a new amp

 

[domct203]

Thanks for the message. Yes I could tell it was coming from one of the "outside" power tubes.
Really mechanically noisy. I went back to the dealer , they installed a new Pair of outside tubes
and it was fine. Later that night the two middle ones started doing the same thing. Along with
some squealing noise that was not a problem before. I know it was just another set of tubes and
perhaps a preamp tube causing the squealing. It was at that point I took the amp back to the store again
and returned it for a refund. The last thing I wanted to do. I know I would eventually retube this amp with
some NOS tubes but I was concerned at this point about long term reliability and just decided that I am done dealing with problems in
a new amp that has not even been gigged yet with less than 6 hours of play time on it. I really loved the way it sounded along with the vast array of sounds I was just starting to discover.
Now back to the drawing board to find a new amp

It appears that the problems you were dealing with were tube related, not a fault of the amp. What were your "long term reliability" concerns? It sounded like you were very happy with the amp.

Anyway, good luck with your tone quest. Just remember, bad tubes can show up in any brand of tube amp.

Dom