Mark IV clicking sound under playing, HELP!!!

[scottieL]

My mark IVa has begun to produce a noticeable clicking sound under my playing, have checked it all out and its not my guitars or effects. Also it has started to hum loudly even with humbuckers, and dimarzio noiseless single coils. Any ideas as to what might be wrong would be greatly appreciated.

 

[MrMarkIII]

It's probably a tube. Get a known good 12AX7, and switch out the pre-amp tubes, one-at-a-time, starting with V1, the tube closest to the input jack. Switch tube, then test the sound. No change? Put the old one back where it was. Next tube. Consult the manual for further info.

 

[MesaDCLP]

Sounds crazy, but mine was doing it too one day. I realized it was my pickups detecting the second hand on my watch!!! haha
Good luck.

 

[scottieL]

wish it were that simple, but I wasn't wearing a watch

 

[primal]

I have read that a hum that starts to increase over time can be unbalanced power tubes, which could mean they are going bad.

With the hum, see if it only happens in Simulclass. If it happens in both simulclass and class A, swap your inner power tubes with your outer ones (PROVIDED YOU ARE USING ALL 6L6's, don't do this if you have EL 34 mixed in).

If you can get to to only happen in Simulclass (this is the hum) then you'll need to replace atleast one set of power tubes.

I had this exact problem with my Mark IV. I had a noticeable hum in Simulclass only. I swapped the inner set with the outer set and all of a sudden I had a noticable hum always! I just said the hell with it and replaced all my power tubes.

The Clicking. I guess it could be related. Is it only when you play? If that is the case it is probably a preamp tube. I have had problems with preamp tubes (on my Roadking) where the sound would sort of click in and out when I played. the problem was there when I wasn't playing, you just couldn't notice it then.

 

[scottieL]

the clicking occurs whenever the volume pot on my guitar is past half.