Microphonic pickup at high gain?

[Morgan138]

After taking a long break from guitar (and going undercover as an upright bassist in country and bluegrass bands) I recently started playing metal again. I don't know if it's that I'm using all different equipment than I used to, or playing with more gain, or just getting fussier, but I've noticed a couple of things that made me wonder whether I have a microphonic pickup:

1. I get a lot of feedback; with a Boss NS-2 I've been able to get rid of most of it but there are times when I swear I can hear it sort of "in the background" while I'm playing, even if I'm picking very tightly and being careful not to leave any strings ringing out.

2. some high notes sustain okay, but others seem to waver out into non-musical feedback annoyingly fast. Initially I thought it might be a dead spot and/or bad intonation, but the guitar sounds very clear and sustains perfectly well when it's unplugged.

3. if I tap on the pickup with a guitar pick it comes through the amp loud and clear.

I'm using an old Ovation Breadwinner (mahogany body, bolt-on) with a Rio Grande Crunchbox in the bridge, through a VTM120 with a full set of new preamp tubes. I remember years ago having similar problems (only much, much worse) with a stock Gibson 490t, and that switching to a DiMarzio Super Distortion made my old SG sound MUCH better, but I thought this Crunchbox was supposed to be a high-gain pickup...

Does anyone have a sense of whether this really does sound like what I'd hear from a microphonic pickup, or does anyone have any experience playing a crunchbox at high gain?

 

[deanbailey]

If you watch the Paul Gilbert instructional DVD (get out of my yard) He shouts into his pickup and it comes through his amp.

I used to do it at a rehearsal too but that was before i knew how ineffective high gain was for rhythms.

 

[RiF]

1. For me it sounds like microphonic tubes in your amp. I have the same effect with my Marshall 6100 head using brand new Electro Harmonix tubes (or even more precise: I never noticed this effect BEFORE the tube replacement). My advise: Ask a tube amp expert which one of the preamp tubes in your amp is responsible the most for microphonic feedback and replace this one with a so-called "low-microphonic" one. These usually have a bit less gain and that's also one of the reasons they are not as microphonic as others.
2. Sorry, dunno...
3. This is perfectly normal. Unfortunately it sounds not good enough to be used as an effect, IMHO.

 

[greyskull]

either you're using too much gain, or your valves or pickup are fucked

 

[ochants76]

thats normal.

 

[Morgan138]

Thanks for all the feedback, everyone! The preamp tubes were my first thought too, but swapping them didn't make any difference - I've never heard of power tubes going microphonic, but is that a possibility as well?

So maybe I'm using too much gain, which certainly seems possible. I'll see if I can dial it back without making some parts sound totally puny - I don't play leads, but do switch around between slow and fast chugging, single string parts, tremolo picking, squeals, etc.

 

[JBroll]

Get the pickups repotted.

Either do it yourself (tons of tutorials here and there, check projectguitar.com and Google any questions you have) or send them off to a pickup maker (Lindy Fralin does this stuff for $10+shipping) and it'll take care of that.

Jeff

 

[Morgan138]

I was reading about potting pickups and it actually looks like fun, but do decent pickup makers really ship badly-potted pickups these days? I wrote Rio Grande to ask about that as politely as I could, but haven't heard back yet...

Might try it anyway though, as a learning experience if nothing else.

 

[JBroll]

You can never be too safe with this stuff - there's not a massive QC conspiracy to ship out microphonic pickups, but basically shit happens and all we can do is wax the balls out of everything and hope to hell it works.

Jeff

 

[Jevil]

I have the same problem with a Rockmaster tube preamp when I turn up the knob to a rehearsing volume.
So I'm still playing with my Pod XT Pro that doesn't sound with feedback even a very high gain and sounds awesome with no speaker simulation.

 

[Morgan138]

Made some progress before practice last night - I reworked my EQ and brought down the overall gain level (blues driver just above unity, high gain preamp knob at 10:00, both gain dipswitches on), and shuffled pedals around so that the preamp was also inside the NS-2's noise reduction loop (don't know why I didn't think of this earlier). I think "too much gain" was the main culprit, but maybe I'll pot those pickups sometime for fun...

Anyhow, thanks for the helpful suggestions.