EVH acting up again

[Coma]

Re: EVH acting up again

Sounds like a pedal or guitar pickup problem to me, not amp. You just said the amp is fine with no pedals in front. That should tell you something.
Are your pickups wax potted ?
Are you using a boost pedal ?

I must say its hard to formulate an overall view of whats going on because you're kind of ambiguous in your selective descriptions.
Prolly not intentional but confusing none the less.

Fair enough, there's a lot to keep track of.


Amp won't squeal:
- With any pedal connected alone, between guitar and in front of amp, provided guitar volume knob is at zero.
- With any pedal connected alone, in FX loop, provided guitar volume knob is at zero.
- With guitar plugged straight into amp, provided guitar volume knob is at zero.
- With guitar plugged in and guitar volume knob at ten, as long as amp volume does not surpass roughly 9 o'clock (in this scenario, gain is at 2 o'clock. Lowering or increasing gain will affect at what point on the volume knob the amp starts to squeal).


Amp will squeal:
- With Boss NS2 connected in X-pattern (first pedal path front of amp, pedal loop through amp FX loop), with amp FX loop bypassed, pedal turned off and guitar volume knob at zero.
- With Boss NS2 connected in X-pattern, with amp FX loop active, pedal turned off and guitar volume knob at zero.
- With guitar straight into amp, and amp volume surpassing 9 o'clock (and gain at 2 o'clock).



- I don't know if the pups for my main guitar are potted, but I have tried with 4 different guitars, three of which have actives and one with passives.
- I have tested every pedal individually to rule out any miscreants other than the NS2, they all seem fine.
- I have tried rigging up my entire pedal board in its usual setup with everything turned off and guitar volume knob at zero - then the amp starts to squeal as well, but not until amp volume hits noon.
- I have tried with two different NS2s with matching settings to make sure mine isn't faulty.
- I have tried swapping multiple tubes in V1 and V4 (which is the first tube in line that isn't shared with the other two channels and also the one that makes the most noise when tapped).
- I have NOT tested swapping the tube in V7, which is the tube driving the FX loop.
- Yes, I have a boost (in the FX loop) and a compressor as well (in front of amp) but the amp will squeal regardless of them being turned off.

[FuseG4]

Re: EVH acting up again

Are your loop fx units on isolated power supply? Pretty sure this would make noise all the time not just above certain volume

The fact that moving the amp off the cab fixes sounds like vibration issues for sure though

Did you say if it does this behavior with nothing in the loop at all? I guess you did say it does it with amp loop bypass

Also If you have any other amps you could try testing the preamp of the evh into the power amp of the other, and see if it still does it... Then you could at least see if it's in the preamp, maybe in the loop, or the power amp that way

[chadd]

Re: EVH acting up again

I'd certainly start with tube rolling and go from there. If you have a tube amp, you should always have some spares that you know are good anyway.

Im sorry but in 2020 if people in general see no difference between a 60's/70's JMP Marshall or a made in USA MESA product compared to a Mexican or Chinese made amp/product there is no hope for future generations of musicians.

I use Mesa and Kemper, and I agree that they are built significantly better, but implying that any import amp is junk is a step too far. And I'm certainly not a future generation at this point.

[JMP/HBE]

Re: EVH acting up again

High gain amps compress naturally so you don't need a compressor. Compressors are normally to push acoustic guitars. And you don't need a boost in the loop either the EVH amps have like 8 preamp tubes.


Question : what happens when you take one guitar with one guitar cable & plug it straight into the amp with absolutely 0.00 pedals or anything else ?

Try that and report back.

[Coma]

Re: EVH acting up again

Are your loop fx units on isolated power supply? Pretty sure this would make noise all the time not just above certain volume

The fact that moving the amp off the cab fixes sounds like vibration issues for sure though

Did you say if it does this behavior with nothing in the loop at all? I guess you did say it does it with amp loop bypass

Also If you have any other amps you could try testing the preamp of the evh into the power amp of the other, and see if it still does it... Then you could at least see if it's in the preamp, maybe in the loop, or the power amp that way

Yes, all pedals are on isolated outputs. No daisy chaining anywhere.

I'm inclined towards vibrations being a contributing factor as well. Moving the amp onto the floor and the other end of the rehearsal space doesn't make it go away, but since the amp makes the drum snares on the opposite end of the room rattle, I'm guessing the tubes could too.

Yes, it does squeal with the loop empty, but not when the guitar volume knob is at zero. That only happens with the NS2 connected (with 4 cables. Not when it's just connected in front of the amp).

I do have a small 20 watter I could try that with. Thanks for the tip. I'm guessing I will still need a cab connected to the EVH when running it so as not to blow the OT?

High gain amps compress naturally so you don't need a compressor. Compressors are normally to push acoustic guitars. And you don't need a boost in the loop either the EVH amps have like 8 preamp tubes.

Not all songs we play use distortion all the way through, the compressor is there to even out clean sections, though I keep it on through some distorted songs as a tone shaper. And yes, I do need a boost to cut through when soloing. There's a Peavey 5150 on top of a 4x12, a Sunn 300T through an 8x10 and a big ol' drum kit playing blasting away at all the bit sof the songs I don't play myself

Question : what happens when you take one guitar with one guitar cable & plug it straight into the amp with absolutely 0.00 pedals or anything else ?

Try that and report back.

I already did. It starts to squeal once volume goes up.

[Jacew]

Re: EVH acting up again

Order a bunch of preamp tubes and test switching them each position. Maybe all at once, if you have thaa kany. To me too, that sounds like obvious tube problem (vibrations, and input gain & sensitivity causing squels).

They are not that expensive and good to have at hand anyway.

[Coma]

Re: EVH acting up again

Order a bunch of preamp tubes and test switching them each position. Maybe all at once, if you have thaa kany. To me too, that sounds like obvious tube problem (vibrations, and input gain & sensitivity causing squels).

They are not that expensive and good to have at hand anyway.

Thing is, I have. When I first started having issues I swapped most of them, so they've all been fairly recently replaced. My assumption was that it's something like the tube socket that's vibrating, but amp tech said he couldn't find any such issues, and I don't know enough about amp design to even know where to start searching if I were to pop it open.

[Rex_Rocker]

Re: EVH acting up again

Maybe it's power tubes! They can go microphonic as well, AFAIK.

[Coma]

Re: EVH acting up again

Maybe it's power tubes! They can go microphonic as well, AFAIK.

Those were all swapped less than a year ago when I had a bunch of repair work done on the power amp. I mean, it's not impossible, I just don't think that's highly likely. It was done by the same guy who did the checkup this time, so I figured he'd probably notice if something was afoul there.

[JMP/HBE]

Re: EVH acting up again

Those were all swapped less than a year ago when I had a bunch of repair work done on the power amp. I mean, it's not impossible, I just don't think that's highly likely. It was done by the same guy who did the checkup this time, so I figured he'd probably notice if something was afoul there.

When you say "bunch of work" explain that.

My guess is maybe with extensive "repairs" something is or got screwed up.
Why did you have the repair work in the first place ?

What problems did were you having back then ?
Did it squeal back then before the repairs ?

Once an amp is damaged & had surgery it opens a whole pandoras box of possible issues.
I will say 90% of tube amp problems are tube related in some way.

[FuseG4]

Re: EVH acting up again

Yes you do need a speaker hooked into whatever power amp you're using
Plus how would you know if it still makes the squeal with no speakers hooked up lol
Microphonic power tubes occurred to me too, never hurts to check, have had microphonic power tubes myself but it wasn't like a squeal as much as I would characterize as a metallic ringing that really clearly got worse on low bassy notes and loud chugging

[Coma]

Re: EVH acting up again

When you say "bunch of work" explain that.

My guess is maybe with extensive "repairs" something is or got screwed up.
Why did you have the repair work in the first place ?

What problems did were you having back then ?
Did it squeal back then before the repairs ?

Once an amp is damaged & had surgery it opens a whole pandoras box of possible issues.
I will say 90% of tube amp problems are tube related in some way.

Amp was burning power tubes (redplating). Either a bunch of components in the power section had fried, taking the tube with them or the hot tube had fried components underneath it. Either way it was smoking and smelled real foul. Had the tubes and busted up components replaced and then the amp re-biased.

It did not squeal before repairs, nor did it squeal directly afterwards.

[Coma]

Re: EVH acting up again

Yes you do need a speaker hooked into whatever power amp you're using
Plus how would you know if it still makes the squeal with no speakers hooked up lol
Microphonic power tubes occurred to me too, never hurts to check, have had microphonic power tubes myself but it wasn't like a squeal as much as I would characterize as a metallic ringing that really clearly got worse on low bassy notes and loud chugging

No, I mean if I'm using the FX loop out from the EVH into the power section of another amp, does the EVH still need to be hooked up to a speaker so its power amp has a load?

It also occured to me that the EVH actually has a line out, though I'm guessing that's located after the power amp.

[ErikH]

Re: EVH acting up again

No, I mean if I'm using the FX loop out from the EVH into the power section of another amp, does the EVH still need to be hooked up to a speaker so its power amp has a load?

It also occured to me that the EVH actually has a line out, though I'm guessing that's located after the power amp.

Yes, it still needs a load or the output transformer will cook. The line out is typically a preamp out, not after the power amp. The power amp out (Speaker outs) level is much too high for line level.

[JMP/HBE]

Re: EVH acting up again

Amp was burning power tubes (redplating). Either a bunch of components in the power section had fried, taking the tube with them or the hot tube had fried components underneath it. Either way it was smoking and smelled real foul. Had the tubes and busted up components replaced and then the amp re-biased.

It did not squeal before repairs, nor did it squeal directly afterwards.

A thermionic valve amp should never get to that point but it happens.

You could have damage to the traces on the PCB or God knows what else permanent damage.

You have to ask yourself how much money am i going to throw at this $500 amp ?

Personally i would get something else thats not SNAFU'd/FUBAR'd.