Mark IIC+ V1 Tube question

[squreg]

Hi,
I have a question regarding a noisy V1 in my 60W rev NON EQ Mark IIC+. I recently purchased it from a local Music shop and everything works fine. The current pre amp tubes are Sovtek (type? I have no idea) and the power amp has Winged C's.
I have experience with mesa amps (I own a Dual rec, Trip Rec, Mark 5, Blue Angel, Mark III) so I am familiar with changing tubes etc.
I wanted to see if a new tube in V1 would make the amp a little quiter so I bought a brand new Mesa SPAX7 and replaced the Sovtek. And when I fired up the amp the it sounded great but the feed back and microphonics were even worse, to the point where touching the power and standby switched was causing a hi pitch sound. I have never had this "problem" with any of my amps in the past 15 years, I would simply get new Mesa tubes every once and a while and they always worked fine. Here is how I had the amp set

Vol1 set to 8 pushed in
Treb set to 7 pulled
Bass 2 pushed in
Mid 3.5
Master1 set to 2 pushed in
Lead Drive 8 Pulled
Lead Master 4 pulled

Cab was Mesa Recto 212. As I mentioned the tone was great (a little brighter then the old tube as you would expect from a new pre amp tube) but the microphonics were bad, it also picked up some radio, and even with the guitar unplugged the amp would feedback when Vol 1 approached 8. Is there a problem with the new tube, or could it be another tube down the line. Any suggestions would be appreciated.

 

[Boogiebabies]

Your issue should not be limited to just the V1. The V2 for the loop, V3 and V4 for the reverb and the PI could have the same issue. PI's rarely make noise but they still can be the culprit. Try a new tube in each socket until the issue goes away, plus test with the reverb on and off. If the noise goes away, problem solved unless your reverb squeals. The only other reason for a bad squeal could be a bad filter cap allowing AC to the preamp.

 

[squreg]

It does not have a shield, I will try that to see if it helps.
Reverb has no change in the noise so I guess it rules that out.
I will try changing individual tubes (including the power tubes) to see if another one is bad.

Thanks a lot, I will let you know how it goes...

 

[Boogiebabies]

A shield will not help, I actually feel that they not only cause issues but also the tone changes a bit. Call me nuts, but I prefer no shield.

If the tube replacement does not help, pull the chassis and look for yellow goo leaking from
the big blue filter caps. specifically the four 30uf/500V ones. Seeing goo is a 100% failure, but not seeing goo does not mean that the cap is good.