High squeel feedback (also on clean)

[ShredZ]

I have this strange issue with my amp on certain guitars. It is a very high squeeling feedback noise coming through (even when playing) with distortion, but it also occurs on the clean channel in some cases. I don't mind feedback, but this is something beyond feedback. Guess sonic youth might like it or something.

Some guitars (notably my les paul standard faded and my schecter c-1 fr custom) have it really bad, like even when you just slide across the high b string when using the bridge pickup. My jackson soloist doesn't have the issue. I tried plugging in a guitar with SD blackouts and the feedback doesn't occur, but the sound is extremely dull compared to say a parallel axis distortion pickup or the TB-4 in the soloist. I had this issue on both an engl ritchie blackmoore head and on a fryette sig-x. These aren't exactly dodgy amplifiers or dodgy guitars/pickups. Can anyone shed some light on what might be causing this ?

Bad cable, tube, speaker, power issues ? I tried plugging straight into the amp and swapping guitar cable and speaker cable, but to no avail. Is the power grid just completely screwing me over, are the tubes too close to the power plug (they are litteraly only a few inches from it). Even the basic furman doesn't seem to have any effect.


If I want to get rid of it I have to set my NS-2 noise gate or the one in my G-Major 2 quite low on the threshold which is up to a point my harmonics are being dampened way too easily.

Any suggestion is welcome as this is really preventing me from enjoying what should be some very high quality gear. :banghead: (ow yea, speaker cab is a marshal 1960AV with the stock V30's in it)

 

[Funkfingers]

Re: High squeel feedback (also on clean)

Er, you have not stated what loudspeaker enclosure(s) you use with the amp heads.

If it is the same cab and cable with both amplifiers, try another speaker cable. (You are using proper loudspeaker cable and NOT an instrument cable, aren't you?!)

 

[ShredZ]

Re: High squeel feedback (also on clean)

Yup, I've tried 2 different kinds of speaker cable, one basic 2-wire "unshielded" and one with gold-plated jacks and a thick cable. The blackmoore was with engl V60 standard cab, the fryette on the 1960AV cab.

Er, you have not stated what loudspeaker enclosure(s) you use with the amp heads.

If it is the same cab and cable with both amplifiers, try another speaker cable. (You are using proper loudspeaker cable and NOT an instrument cable, aren't you?!)

 

[erksin]

Re: High squeel feedback (also on clean)

Sounds like either a microphonic preamp tube or you're using unpotted pickups with your high gain which will most definitely create squeal.

 

[ShredZ]

Re: High squeel feedback (also on clean)

I'll look into the pickup issue, but you'd expect the custom custom in the schecter or the gibson pickups to be properly taken care of.

If it is a microphonic preamp tube, how do I find out which one to swap or should I just move it around the room to see where it doesn't pick up whatever it's picking up ?

Sounds like either a microphonic preamp tube or you're using unpotted pickups with your high gain which will most definitely create squeal.

 

[post toastie]

Re: High squeel feedback (also on clean)

Cone Cry ?

 

[Chickenwings]

Re: High squeel feedback (also on clean)

tubes.
its a tube amp. when things go bad its nearly always the tubes. Checking the tubes is the first thing anyone should really do when thing start to go pear shaped.
heres a couple of things you can do:
try gently tapping on each of the preamp tubes with a chopstick or something. See which one is ringing.
swap out each preamp tube with a known good one and see the results.
if either of these find your problem then great! the job is done!
....but its proabably due for a full new set and keep the old (working) ones as spares for a gig.

 

[whatshisname]

Re: High squeel feedback (also on clean)

tubes.
its a tube amp. when things go bad its nearly always the tubes. Checking the tubes is the first thing anyone should really do when thing start to go pear shaped.
heres a couple of things you can do:
try gently tapping on each of the preamp tubes with a chopstick or something. See which one is ringing.
swap out each preamp tube with a known good one and see the results.
if either of these find your problem then great! the job is done!
....but its proabably due for a full new set and keep the old (working) ones as spares for a gig.

Gibson175 has got it covered. :approve:

 

[Warheart]

Re: High squeel feedback (also on clean)

+1 to Gibson175.

Assuming it still makes the noise when your guitar isn't plugged into the amp.

 

[erksin]

Re: High squeel feedback (also on clean)

Well he's having it in multiple amps with multiple guitars - unless he's having an extraordinary run of bad luck or just plain boosting the living **** out of his preamps, it isn't necessarily a tube issue.

Are you running through the same cab each time? The cone cry thing is certainly a possiblility, but I don't know why the noise gate would quash that.

 

[Chickenwings]

Re: High squeel feedback (also on clean)

Well he's having it in multiple amps with multiple guitars - unless he's having an extraordinary run of bad luck or just plain boosting the living **** out of his preamps, it isn't necessarily a tube issue.

Are you running through the same cab each time? The cone cry thing is certainly a possiblility, but I don't know why the noise gate would quash that.

nah its just one amp and multiple guitars....read his thread

 

[erksin]

Re: High squeel feedback (also on clean)

"Some guitars (notably my les paul standard faded and my schecter c-1 fr custom) have it really bad...

I had this issue on both an engl ritchie blackmoore head and on a fryette sig-x. These aren't exactly dodgy amplifiers or dodgy guitars/pickups."

Sounds like multiple amps and guitars to me.

 

[woemoejack]

Re: High squeel feedback (also on clean)

I've had a similar thing happen to me and it was a micro-phonic tube. My amp has a cooling fan on the transformer and you could hear it coming in the signal, really high pitched noise, always there. Swapped out one bad tube, voila.

 

[Chickenwings]

Re: High squeel feedback (also on clean)

"Some guitars (notably my les paul standard faded and my schecter c-1 fr custom) have it really bad...

I had this issue on both an engl ritchie blackmoore head and on a fryette sig-x. These aren't exactly dodgy amplifiers or dodgy guitars/pickups."

Sounds like multiple amps and guitars to me.

yeah fair enough!

I still reckon fisrt thing he should eliminate is the possibility of a microphonic tube in the preamp section.

 

[ShredZ]

Re: High squeel feedback (also on clean)

I'm gonna check the tubes tomorrow, since plugging the worst squeeling guitar into our other guitarist's dual rectifier on serious gain only yielded what you'd consider regular feedback.

yeah fair enough!

I still reckon fisrt thing he should eliminate is the possibility of a microphonic tube in the preamp section.