Time for a pre-amp retube... bummer

[devilrob1979]

Actually it's not a bummer as I've been wanting to put a Dougstubes cocktail in my Mark IV but now it's becoming a necessity. My lead channel is squealing like a pig anytime there's a pause in playing. This occurs with the presence at zero and the gain set from anywhere from 2 and up. Nothing like a little micrphonic pre-amp tube action. Good Lord it's horrid.

 

[mule#1]

I'll second that! I just retubed the preamp tubes and I'm doing the power tubes tonight!

 

[ANIMATED SUSPENSION]

Does the squealing stop if you turn off the volume on the guitar ?? If it does it's not a preamp tube problem.The treble control will have way more effect on squealing than the presence too. Try reducing it and compensating with the graphic.

 

[devilrob1979]

Why's the thing squealing so much then? It's doing it with all of my guitars and my co-guitarist's who uses EMGs so I don't think it's a noise issue. Any thoughts?

 

[guitardude05]

ive always had this problem with my mark iv on the lead channel. its just the high gain i guess... but my friends p.o.s. randall doesnt squeall at all at over 2x the volume i can put the mark.

my solution: noise gate... still dont have one :lol:

 

[devilrob1979]

Hmmm, so is a Rocktron Hush the favorite still?

 

[disassembled]

You can move your preamp tubes around to see if that gets rid of the microphonic squeal. I would say swap out V4 or V3 with V1 or maybe V5 instead of V4. This will buy you some time instead of forcing you to retube. Does your amp have the extra tube?

Greg

 

[devilrob1979]

Yeah my amp has all 5 pre-amp tubes and I had planned on swapping around to isolate the problem.