Channel 2 odd noise

[dmcguitar]

So I've had my mark for a few months now and can't seem to figure out this odd distortion I great on channel 2. Ch 1 seems fine, and 3 maybe affected but there is so much gain that it is masked. I notice it the most on edge and crunch.settings of the dials don't matter much. I have tried 2 different vert recto cabs and my 23"express cab and the found is still there, also there with my EMG loaded LP, ebmm jp6, ibanez rg (all guitars really) I can only describe it as what a ripped speaker might sound like, or if you put a piece of paper in front of a loud amp... Or possibly the sound a snare drum with the snare very loose

Can anyone check if they hear this and if its part of the amps sound, or if maybe I have an issue... It is quite evident when I play an open g string, and the notes on that string..

Also I have swapped out with el34 tubes, doesn't help, I have a new recto tube (which cleared up a different issue, this sound was there for both) and I have one by one swapped the preamp tubes with a new one that mesa shipped me, but never noticed a change as it went into the different spots.


unrelated, do I have to leave the preamp tube covers on?

Thanks

 

[eudaimonia02912]

My first thought was that it has to be the pre-amp tube in V2. You're having a problem only on channel 2, V2 only affects channel 2, and your problem sounds like a tube problem. However, if you've tried swapping all the tubes, then I'm unsure.

 

[dmcguitar]

I'll try v2 again and post back...that's one of the three in the triangle formation right? I have a replacement 12ax7 and some other type of that tube, called a spax7 or something like that...any ideas of the differences

Thanks

 

[eudaimonia02912]

Facing the inside of the amp from behind, the pre-amp tubes are arranged like this:

7 6 5 4 2/3 1

V2 and V3 are stacked together, with V2 closer to the front of the amp (farther away from you when changing tubes from behind) and V3 closer to the back of the amp (closer to you as you change tubes).


The SPAX7 is selected for low noise; otherwise it's the same as a regular 12AX7. It's best used in early gain stages like V1 to lower the noise floor of the amp.

 

[dmcguitar]

doesnt seem to be a tube issue, but something inherent in the amp. I put the spx7 in the 2 slot and found no difference. So i went to GC and played a MKV head through a vert 2x12 and a MKV combo (both pretty new to the store, not mine) and found that I got the same annoying noise, so I believe it is probably bad choice in knob settings that makes it more apparent.

With that said. Any thoughts on dialing in Ch 2 for edge or crunch? I am looking for a good rush type crunch. say the late 80's presto - counterparts era. "show don't tell" comes to mind. any ideas, am i barking up the wrong tree with my mark V? do i just need to add chorus to the crunch or something?

I have a EBMM BFR JP6 if that helps.

thanks all!