Microphonic pickups?

G

guitarjunkie986

New member
Hey all,

I installed a set of SD Distortions in my Ibanez 7421 about 3 years ago and never had any issues over the first year where I played it pretty heavily. It's been stored in its case in a closet for about a year and a half. I took it out for a rehearsal yesterday and it was pretty much unusable due to screeching feedback anytime the lead channel gain was over 4 or if my overdrive was on. The feedback occurs even if muting the strings and without having even played a note. It occurs on both pickups, all positions. There are no issues with noise or feedback on the clean channel however.

I looked at the wiring and don't see any issues, and everything sounds as expected on clean and dirty (with the exception of the feedback while not playing). I tested with 2 different amps and the same issue occurs with this guitar. All of my other guitars are fine with the same gain levels and settings. Should I just rewire everything? Replace pots and output jack? I find it odd that there'd be an issue with both pickups when it wasn't an issue before.
 
Re: Microphonic pickups?

Normally the wax potting of a pickup does not go bad over a short period. Were you using different amp settings or a new pedal in the interim?
 
Re: Microphonic pickups?

My setup is a bit different than when I last used this particular guitar, but it is similar. When I last used it I was playing through a Peavey 6505+, boosted with an SD 805. I'm currently using a 6505, boosting with an Airis Effects Savage Drive. I'm not adding any gain with the boost, just using them to tighten things up. The feedback occurs even without using the boost though, and I have other guitars that have pickups similar in output that don't have this problem (DiMarzio Blaze Custom, SD Custom 5, EMG 81, etc). This guitar hasn't been subjected to any extreme temps or humidity so I wouldn't expect it to be a potting issue even though the symptoms kind of point to the pickups.
 
Re: Microphonic pickups?

Something like a loose bridge is normally manifested as something like a ringing after notes. Since your bridge is fairly simple I don't think it would have shifted much if it was unused. There's probably foam underneath the pickups in a direct mount and it wouldn't have deteriorated much since last use so I'm not sure that would be it either? Are the pickups loose? What do the solder joints look like are they smooth silvery puddles or are they dark globs? Repotting the pickups isn't hard but you might as well elimintate everything else first.
 
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Re: Microphonic pickups?

First of all...quit looking at your guitar. Unless you have evil gremlins or your house is haunted by poltergeists, nothing AT ALL in your guitar will change from being stored unused for a year or two. The only things that have changed are your booster and your amp settings.

Some pups under certain gain and boost settings will squeal, others will not. If you don't want the pups in that guitar to squeal, you need to change some settings.

Several years ago I used to eat Fuji apples in the afternoon for a snack. I just recently started eating grapefruit as a snack and now my mouth is all sour and prickly. My eating habits are similar and the snacks are both fruit. What's wrong with my mouth? It didn't used to do this. And when I eat different types of apples this doesn't happen. Maybe I need to go to a doctor and have my mouth checked.
 
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Re: Microphonic pickups?

I think this might be an issue of gain staging- hitting the preamp too hard, and then increasing the gain after that.
 
Re: Microphonic pickups?

I find that well made PAF replicas that are unpotted don’t squeal to easily and have the qualities you mentioned. If a pickup is too mucrophonic it can be unpleasant.


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Re: Microphonic pickups?

GuitarDoc said:
First of all...quit looking at your guitar. Unless you have evil gremlins or your house is haunted by poltergeists, nothing AT ALL in your guitar will change from being stored unused for a year or two. The only things that have changed are your booster and your amp settings.

Some pups under certain gain and boost settings will squeal, others will not. If you don't want the pups in that guitar to squeal, you need to change some settings.

Several years ago I used to eat Fuji apples in the afternoon for a snack. I just recently started eating grapefruit as a snack and now my mouth is all sour and prickly. My eating habits are similar and the snacks are both fruit. What's wrong with my mouth? It didn't used to do this. And when I eat different types of apples this doesn't happen. Maybe I need to go to a doctor and have my mouth checked.
Click to expand...

I understand this in principle, but like I mentioned, even taking my pedalboard out of the equation and running directly into the amp with gain set to 4 or less as volume is increased on my 6505 (which certainly isn't over the top) it squeals uncontrollably. The results are the same with my VHT Deliverance with very modest gain levels. I have 12 other guitars (most with high output pickups and one with the same model pickup) and this guitar is the only one that does this. Logic would dictate that there is something up with this guitar. Suggesting that I just shouldn't play at rehearsal volumes, or shouldn't have the gain up to 3 or 4 isn't really a solution. The only thing this guitar is capable of without feedback at the moment are clean tones, which isn't what someone buys a Distortion for.
 
Re: Microphonic pickups?

If you are suggesting that your guitar didn't squeal before you stored it but now it does, well, I guess we have to conclude that your guitar is haunted. I don't have any suggestions for fixing that.
 
Re: Microphonic pickups?

GuitarDoc said:
If you are suggesting that your guitar didn't squeal before you stored it but now it does, well, I guess we have to conclude that your guitar is haunted. I don't have any suggestions for fixing that.
Click to expand...

I was really just kind of asking here to see if anyone had ever had symptoms like this and where to start. I didn’t know if something like this could be caused by a jack or pot that had failed or something else.

I’ll replace the pots and the output jack and rewire everything before I call in an exorcist.
 
Re: Microphonic pickups?

I honestly haven't heard of this happening unless something else about your rig changed since you'd played it. Does it do it though other amps, in other buildings? I'd love to know if you figure it out what it might be, though.
 
Re: Microphonic pickups?

We had a Tele here that had microphonics due to the string tree screw on the headstock getting loose...
 
Re: Microphonic pickups?

It does seem odd because it is BOTH pickups. My only suggestion is to carefully go over the entire guitar with a screwdriver checking to make sure everything is properly snug?
I can't imagine strings causing this but if you haven't already you might try changing them?
I am baffled as you are.
 
Re: Microphonic pickups?

Are your speakers and speaker cabinet the exact same, and are you in the same room, standing the same distance and orientation as the last time you used the guitar without problems? If not, that would be my guess, given all the other variables that were ruled out.
 
Re: Microphonic pickups?

beaubrummels said:
Are your speakers and speaker cabinet the exact same, and are you in the same room, standing the same distance and orientation as the last time you used the guitar without problems? If not, that would be my guess, given all the other variables that were ruled out.
Click to expand...

Occurs with the cab that stays at the rehearsal space, as well as 3 cabs that I have at my house. Obviously if I'm closer to the cab it's worse, but still occurs even 10-12 ft away. I even run a noise gate, but the feedback is strong enough that the gate doesn't clamp down unless I crank the gate up all the way, which is cutting off actual notes as well. I normally only have my gate up to about 10-11 o'clock and it works perfectly for the rest of my guitars.

I went through all the screws and everything seemed to be plenty tight. I should have some time tonight or tomorrow to try a new volume and tone pot and replace the output jack. Just trying to start with components that would affect both pickups.
 
Re: Microphonic pickups?

10-12 feet? How freeking loud are you playing and how big is the room? So if you stand 13 feet it stops?
 
Re: Microphonic pickups?

beaubrummels said:
10-12 feet? How freeking loud are you playing and how big is the room? So if you stand 13 feet it stops?
Click to expand...

At my house I'm in a smaller room and probably only get about 4-5 feet away tops. Our rehearsal space is a basement so it's pretty large. At rehearsal I'm loud enough to compete with a pretty heavy handed drummer. Usually at about 3.5 on the post gain of a 6505. At home though I'm only running around 1.5 on the post.

As far as the noise stopping at 13 feet I'm not sure as I didn't troubleshoot too long at rehearsal. I just switched to another guitar so as not to hold up practice.
 
Re: Microphonic pickups?

The only other thing to try is being way off axis from the cone of the speakers, if you haven’t tried that already.
 
Re: Microphonic pickups?

Did it get super hot where the guitar was stored? Like hot enough to melt the wax potting out of the pickups?
 
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