Mark IV squealing any ideas????

[mule#1]

Hopefully you guy's can help! my IV is squealing whenever I take my fingers of the strings badly. Could I need new tubes? From the back the 2 6L6's to the right glow with a little blue around the glass (so class A and Simul tubes are affected) or could it be 12AX7's? Any ideas. I plug the same Les Paul into the same cab(EV's) using my 50+ and it is fine. Any ideas are appreciated.

 

[eet fuk]

I HIGHLY recommend the ISP Decimator pedal in front of the amp. With gain and volume and distance from the amp, there's no escaping the feedback. Unless you're a weak and farty R2 kinda guy. KIDDING. With the decimator, I could stand right next to my cab and between sudden chord stops, ZERO feedback with the pedal only on 3-4. And it kills tone the least of all gates, I tried em all.

 

[bryan_kilco]

I HIGHLY recommend the ISP Decimator pedal in front of the amp. With gain and volume and distance from the amp, there's no escaping the feedback. Unless you're a weak and farty R2 kinda guy. KIDDING. With the decimator, I could stand right next to my cab and between sudden chord stops, ZERO feedback with the pedal only on 3-4. And it kills tone the least of all gates, I tried em all.

I run a Boss NS-2 before my amp and it works wonders. Heard good things about those Decimators though.

 

[eet fuk]

I have the ns2 for my other amps. Decimator blows it away for the mkIV, though, IMO.
I somehow missed that part about the orig post taking the hands off the strings and getting the problem. NOPE, no problem, that's just how it is, potentially with a gate too even for ultra high gain leads. Muting is the key.

 

[MesieBooga]

Most likely a preamp tube. Check V1 1st- replace it w/ a new one (Groove Tube 12ax7M's are cool)

 

[stoz]

How about turning the gain down a tad, does that stop it?

 

[eet fuk]

Turning down the gain, stepping away from the amp, and turning down the volume all will diminish feedback. The JVM guys have this "problem" in spades. Oh yeah, good call on swapping preamp tubes to find a potential culprit squealer. I have had a great deal on an amp due to mere faulty preamp tubes. One quick swap, and presto! New amp. The gas hitting me for a mkIV is at an all time high. I'm afraid you guys are going to have to put up with me for awhile.

 

[mule#1]

Yeah...turning down the gain and swapping tubes did the trick. Thanks for the replies!