Howling Feedback on High Gain amps problem AXE MK II

[romanianreaper]

This was my first thought.

Are your pickups potted?

I was going to ask the same thing. I just got new pickups and they howl more than my other guitars.

 

[jonhep]

Also check your input levels. I have found turning those down can get rid of this type of problem with certain guitars

 

[Rexxyboy]

Not sure if my pickups are potted, i use Suhr Aldridge pickups in my Jackson and my Les Paul, similar to a Dimarzio Super Distortion. My Axe FX input level is Zero.

 

[KevinP]

I had this same issue using a 2 x 12 with a poweramp at a recent festival style show. Turning down the axe output to around 8-9 o'clock and then turning the power amp up took care of it. The Axe was mounted in a 6 space shock rack with the poweramp right below it, and the 2 x 12 sitting on the top of the rack. I won't be using this setup again hopefully, so not too worried about it. BTW amps were basically any recto modern and the dizzy stuff.

 

[Rexxyboy]

Tmro is the day i set up in a rehearsal space and make ton of noise, will report in! Its funny, at the last gig i left my high gain rhythm patch on with my guitar volume down during a drum solo - i leant over to my my FR212 and i could hear drums coming thru my speaker, not super loud, but noticeable. Picking up a longer 4 metre speakon lead today so i can move the rack around if need be.

 

[Rex]

Its funny, at the last gig i left my high gain rhythm patch on with my guitar volume down during a drum solo - i leant over to my my FR212 and i could hear drums coming thru my speaker, not super loud, but noticeable.

If you could hear the drums in your speaker—and the sound wan't drowned out by the drum kit—that's either way too much gain or a microphonic pickup. Have you tried another guitar?

 

[Rexxyboy]

If you could hear the drums in your speaker—and the sound wan't drowned out by the drum kit—that's either way too much gain or a microphonic pickup. Have you tried another guitar?

It was a drum solo, so my guitar volume and volume pedal were off, just the drums playing on their own, just the axe fx doing its microphonic thing!

Your patch tweak did help Rex so thanks again mate. As well as that I bought the longer speakon cable today and put the rack a metre or more to the side, ran it up brutally loud, so far so good here in my small bright gear room But, i'll get it to rehearsal room on Wednesday where i can be sure.

I tried my Les Paul which has the same pickup, and apart from more thickness and body, it sounded pretty much the same as the USA Jackson. There are loud subs under the stage at the regular gig i do, i don't think that's helping my cause, but hey, its all rock'n'roll eh !

 

[raymitchell]

It may seem elementary or silly, and it may be that you've tried this already but, since you were hearing bits of drum solo coming through the cab with the volume pedal rolled off and the guitar's volume rolled off as well, that would make me try different cables from the Axe Fx to the inputs on the Matrix.

Additionally, I'd try different cables from the guitar to the Axe (or from the wireless to the Axe if you're using a wireless). Oh, and speaking of a wireless, if you happen to be using one, bypass it and plug straight into the Axe. Also, if you are indeed using a wireless, which model are you using and have you adjusted the bodypack's output by any chance? I'm asking this because I know some players will juice the bodypack output or the wireless output in order to make it hit the frontend of an amp a bit harder.

Another thing you could try is making up or buying some TRS to TS cables and use them to feed the Matrix. I've eliminated some really goofy squeals and oddball hums in the past by using isolation transformers inline between two pieces of gear that, theoretically shouldn't need isolation transformers between them at all.

Another goofy question, do the Axe and Matrix touch each other in the rack? Have you tried the old Friedman trick of sanding the finish off the back of the rack ears on the Axe Fx and the Matrix so they make full contact with the rack rails? Do the rack ears or rails have any sort of coating or finish on them?

I know some of my suggestions may seem a bit extreme but, what you're describing is giving me flashbacks to chasing bad cables and/or ground loops from my days of building guitar racks with multiple preamps, pedals, and effects units.

From what I've read here, and after looking at your preset file, I don't see anything in particular that should be causing you any issues.

 

[KevinP]

When I was having the howling issue I went as far as turning off my wireless transmitter on the guitar and unplugging it, and still had the issue. That tells me for sure it wasn't the guitar, but rather the Axe picking things up. But my output volume was up a lot, so turning it down did solve it.

 

[Kriig]

It was a drum solo, so my guitar volume and volume pedal were off, just the drums playing on their own, just the axe fx doing its microphonic thing!

Your patch tweak did help Rex so thanks again mate. As well as that I bought the longer speakon cable today and put the rack a metre or more to the side, ran it up brutally loud, so far so good here in my small bright gear room But, i'll get it to rehearsal room on Wednesday where i can be sure.

I tried my Les Paul which has the same pickup, and apart from more thickness and body, it sounded pretty much the same as the USA Jackson. There are loud subs under the stage at the regular gig i do, i don't think that's helping my cause, but hey, its all rock'n'roll eh !

New cables should be tested .... IMHO.....I've come across cables that pickup sound. Them i throw into the bin

 

[Rex]

Another goofy question, do the Axe and Matrix touch each other in the rack? Have you tried the old Friedman trick of sanding the finish off the back of the rack ears on the Axe Fx and the Matrix so they make full contact with the rack rails? Do the rack ears or rails have any sort of coating or finish on them?

At best, that will have no effect. At worst, you're inviting a ground loop. No need to take abrasives to your gear.

 

[raymitchell]

At best, that will have no effect. At worst, you're inviting a ground loop. No need to take abrasives to your gear.

I understand what you're saying, no question. However, the idea in sanding the backs of the ears of the rack gear and in grinding the finish off your rack rails is this: when building traditional rack systems, when you get everything in the rack on the same page ground-wise, it allows you to track down ground loops much more quickly. When everything has a common ground, then the humming/offending pieces reveal themselves for you. When this happens, you know immediately where to stick an isolation transformer or make up a TRS to TS cable, etc. Dave Friedman is the fella who taught me this technique, and man, did it ever help me get my rack(s) behaving. I was using multiple preamps, effect units, and heads slaved into the rack to boot back then.

I can't imagine needing to take such measures as sanding rack ears and grinding rack rails with an Axe Fx/Matrix rig but, I thought I'd throw all options on the table.

 

[Rex]

The problem is, you still have a ground coming to each piece of equipment through the power cords. If signal ground is isolated from chassis ground on all your equipment, sanding will have no effect. If not, you've introduced a ground loop.

 

[raymitchell]

The problem is, you still have a ground coming to each piece of equipment through the power cords. If signal ground is isolated from chassis ground on all your equipment, sanding will have no effect. If not, you've introduced a ground loop.

The idea is to get all chassis grounds on a common ground. Then, debug audio from there.

 

[Rexxyboy]

Reporting back in! Its been a couple of weeks between gigs. The howling has gone now on the loud high gains. It was combination of Rex's gain re-structuring, angling the FR212 back and a metre closer, and having the rack off to one side instead of on top the cab. I 've reverted to the Friedman HBE amp model, sneaked the gain back up to 6, so far so good. Rex in your experience what is a good AMP block parameter to get sweetness on lead tones? Gain tone is great for rhythm, just lacking juice and sustain / squish for lead, Lead tone is a NULL Filter block with 4db before my delay block.

 

[Rex]

Victory! Congratulations!

Rex in your experience what is a good AMP block parameter to get sweetness on lead tones? Gain tone is great for rhythm, just lacking juice and sustain / squish for lead, Lead tone is a NULL Filter block with 4db before my delay block.

That depends on what "sweetness" means to you. To me, lead-tone sweetness means singing mids and a high-end that's rolled back a bit compared to your rhythm tone. There are lots of ways to get there. Here are a few ideas to get you started:

Try playing your leads on your neck pickup. Depending on what you're shooting for, that may be all you need.

Go into the Amp block's GEQ page. Pick one slider (one of the mid sliders is a good place to start). Move it up and down, making note of whether the movement gets you closer to the sound you're shooting for or farther away from it. Leave it at the position that gets you the closest. Repeat for each slider.

To add a strong, fat push to your leads, drop a Filter block in front of the amp. Set it to Peaking mode, at around 800 Hz, with a low Q, and Gain around 4 or 5. Nudge those values around a bit to find what you like best.​