#1
so my bv120 is producing wicked feedback on the gain channel and a hum on the clean channel when i have the reverb tank plugged in. i have unplugged the reverb tank and the hum goes away but the feedback is still there on the gain channel. i have also checked every single preamp tube by going through and swapping out each tube one at a time. and the feedback is still there.
i did notice an imperfection in the glass on one power tube down by where it plugs into the socket. could this be the issue. it looks cracked. im running a matched quad of ruby 6l6gcm-str power tubes. i have a couple groove tube 6l6's sitting around for spares could i pull the one in question and put in one of the GT's to see if the problem goes away? or would this damage my amp and screw up the bias?

the feedback is only an issue when i boost it with my super overdrive. even with the gain on the overdrive all the way down it produces the feedback.

and if this tube is the issue could i order another ruby 6l6gcm-str and just pop it in or would i have to get the bias checked?

thanks in advance
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Michael Kelly Custom Shop Plum Telecaster
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#3
yeah i have one on my board and i use it. noise has never been an issue till 2 days ago. the feedback is there for a second before the gate kicks in.
Live Rig
Michael Kelly Custom Shop Plum Telecaster
Michael Kelly Custom Shop Plum Patriot


EVH 5153 50w
Jet City 2x12
Custom Board

It is NOT trash metal it is tHrash metal...get it right
#4
if the glass of a tube is cracked you need to replace it. if you can see little spots of white on the glass you definitely need to replace it. proper bias is important but you wont mess your amp up playing with a mismatched tube set if they're all 6l6, especially if you only have it that way for a few weeks of use. anyone who tells you otherwise is just trying to scare you
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Last edited by ItsThatDude at Aug 9, 2011,
#5
im about 99 percent sure that the tube has cracked and thats why it is screetching so bad. i mean hell it still sounds fine until i stop playing and wait that second for my noise gate to kick in.
there are no white spots on it but i know it needs to be replaced.
now the main question i have is if i throw one of those groove tubes in there till dougstubes sends me my replacement. will it screw up the bias? dougstubes just emailed me back asking for the label info on the box so they can get a new one out to me ASAP. they are going to match one up to my current set of tubes so i dont have to rebias
Live Rig
Michael Kelly Custom Shop Plum Telecaster
Michael Kelly Custom Shop Plum Patriot


EVH 5153 50w
Jet City 2x12
Custom Board

It is NOT trash metal it is tHrash metal...get it right
#6
ok so i just swapped out the tube in question and the feedback was still there. perhaps use detoxit on all my connections?
Live Rig
Michael Kelly Custom Shop Plum Telecaster
Michael Kelly Custom Shop Plum Patriot


EVH 5153 50w
Jet City 2x12
Custom Board

It is NOT trash metal it is tHrash metal...get it right
#7
id really like to get this figured out.
could my boss super overdrive be going bad? or would it be boosting an already bad signal?
Live Rig
Michael Kelly Custom Shop Plum Telecaster
Michael Kelly Custom Shop Plum Patriot


EVH 5153 50w
Jet City 2x12
Custom Board

It is NOT trash metal it is tHrash metal...get it right