Wax potting vintage pickups

[impaJah]

I've copied and pasted this same post at the BYOC forum when someone recommended this place for better/quicker feedback (lol and it's a question about feedback too ha!) Please forgive my laziness!!

So here's the deal, I recently got a 60's japanese Zim Gar. It's got a great clean tone. Now I like distortion as well and when I run it through my Shredder (distortion pedal) and really ramp up the distortion there's an insane amount of feedback all the time. I was thinking this was because these old guitar pickups weren't wax potted because the technique wasn't invented yet. I did some searching on google and strangely I couldn't find anything on people wax potting vintage pick ups. Maybe everybody's more sentimental than I am about old stuff? I don't care I just don't want to ruin the pickups if I do this.

What I want to know is if wax potting is possible on older pickups and if this is likely the reason for the insane feedback? Are there any other solutions?

Thanks!

p.s. I came up with the bright idea that if I got a strong magnet I could just hover it over the pickups and it would be enough to overload the input on the electromagnets, thus eliminating the feedback. Well the magnet came in today and I tried hovering it over those pickups as the incessant feedback drone filled the room and when I tried moving it closer (since it wasn't working) the magnet snapped to the pickups with such intensity that I flinched back as if a gun had gone off. Now you all can have no doubt that waving a magnet over pickups will not effect them in any significant way!

[copperheadroads]

I've copied and pasted this same post at the BYOC forum when someone recommended this place for better/quicker feedback (lol and it's a question about feedback too ha!) Please forgive my laziness!!

So here's the deal, I recently got a 60's japanese Zim Gar. It's got a great clean tone. Now I like distortion as well and when I run it through my Shredder (distortion pedal) and really ramp up the distortion there's an insane amount of feedback all the time. I was thinking this was because these old guitar pickups weren't wax potted because the technique wasn't invented yet. I did some searching on google and strangely I couldn't find anything on people wax potting vintage pick ups. Maybe everybody's more sentimental than I am about old stuff? I don't care I just don't want to ruin the pickups if I do this.

What I want to know is if wax potting is possible on older pickups and if this is likely the reason for the insane feedback? Are there any other solutions?

Thanks!

p.s. I came up with the bright idea that if I got a strong magnet I could just hover it over the pickups and it would be enough to overload the input on the electromagnets, thus eliminating the feedback. Well the magnet came in today and I tried hovering it over those pickups as the incessant feedback drone filled the room and when I tried moving it closer (since it wasn't working) the magnet snapped to the pickups with such intensity that I flinched back as if a gun had gone off. Now you all can have no doubt that waving a magnet over pickups will not effect them in any significant way!

If it squeals & it undesirable then pot it (whether you worried about the vintage value & how potting an unpotted pup could affect it's value of it ,is up to you )
Magnets/recharging wont prevent feedback but recharge the magnets & possible make it stronger & possibly loose some of the vintage tone

[impaJah]

If it squeals & it undesirable then pot it (whether you worried about the vintage value & how potting an unpotted pup could affect it's value of it ,is up to you )
Magnets/recharging wont prevent feedback but recharge the magnets & possible make it stronger & possibly loose some of the vintage tone

I know these next questions are probably very obvious to you but I want to confirm everything because I don't want to mess this up.

So the problem probably is that these pickups aren't wax potted (being that it's a guitar from the 60's)?

Are there any problems or difficulties I should look out for wax potting vintage pickups?

Will it get rid of all feedback or just the incessant kind that overpowers everything? I would still like to have some feedback for instance when I put the guitar close the speaker.

Thank you very much for the reply copperheadroads!! I really appreciate it!!!!

[Stratz]

So the problem probably is that these pickups aren't wax potted (being that it's a guitar from the 60's)?

Are there any problems or difficulties I should look out for wax potting vintage pickups?

I would still like to have some feedback for instance when I put the guitar close the speaker.

Wax potting of guitar pickups has been a common practice since long before the sixty's.
If you pot your pickups you will still get the desireable feedback but the microphonic (bad) feedback will be gone.

If you used a permanent (neodymium) magnet and it stuck to the pickups then there's a very good chance that you altered the strength and possibly even the polarity of the magnet or magnets which would cause some very undesirable results.

The strength (Gauss level) of the magnets is critical to the pickups sound and performance.

I recommend that you keep neodymium magnets far away from your pickups.

I don't know how many pickups your model has or if they're single coil or humbuckers but I suggest you contact a pickup builder that will check and possibly restore the Gauss levels.
If you didn't disrupt all of the magnets he may be able to get an average reading from them and then he will be able to restore them to where they were before you put the magnet to them.

[impaJah]

Wax potting of guitar pickups has been a common practice since long before the sixty's.
If you pot your pickups you will still get the desireable feedback but the microphonic (bad) feedback will be gone.

If you used a permanent (neodymium) magnet and it stuck to the pickups then there's a very good chance that you altered the strength and possibly even the polarity of the magnet or magnets which would cause some very undesirable results.

The strength (Gauss level) of the magnets is critical to the pickups sound and performance.

I recommend that you keep neodymium magnets far away from your pickups.

I don't know how many pickups your model has or if they're single coil or humbuckers but I suggest you contact a pickup builder that will check and possibly restore the Gauss levels.
If you didn't disrupt all of the magnets he may be able to get an average reading from them and then he will be able to restore them to where they were before you put the magnet to them.

To be honest I've played it after and it sounds roughly the same. If there's a little extra pickup strength around the middle strings compared to the outer ones then oh well I guess it'll sound unique - but I didn't notice anything since I've played it.

Thanks for the advice about magnets!!!

[SonnyW]

I know these next questions are probably very obvious to you but I want to confirm everything because I don't want to mess this up.

So the problem probably is that these pickups aren't wax potted (being that it's a guitar from the 60's)?

Are there any problems or difficulties I should look out for wax potting vintage pickups?

Will it get rid of all feedback or just the incessant kind that overpowers everything? I would still like to have some feedback for instance when I put the guitar close the speaker.

Thank you very much for the reply copperheadroads!! I really appreciate it!!!!

As far as your question about problems or difficulties wax potting them, it definitely needs to be done at a low temperature and you could run into some problems depending on which pickups it has. Are they the ones that look like the Teisco Gold Foils? There were a lot of the Zim Gar models.

[CRU JONES]

If you like the tone, consider not f'ing with it

If they are anything like the Teisco pickups I have inspected, (which sound awesome!) they are very much a microphone.

Generally speaking:

A microphone is a moving coil in a stationary magnetic field.
An electric guitar pickup is a stationary coil in a moving magnetic field.
...The Teisco Gold foils are a combination of both.

Wax potting is the reason I have been able to take them apart and fix them I have also owned a few perfectly working teisco's and can tell you that the "moving coil" part is sensitive to near 5kHz. The "moving field" part has a corner frequency around 1kHz... Not very high!

Obviously by wax potting you will stop the coil from moving. Sort of like wax potting a SM57

Many of the Teisco guitars have the "pickups" labeled as "mic". They aren't kidding. Maybe your pickup isn't like a Teisco, so take my two cents with a grain of salt.

Cheers,
Ethan

[David Schwab]

p.s. I came up with the bright idea that if I got a strong magnet I could just hover it over the pickups and it would be enough to overload the input on the electromagnets, thus eliminating the feedback. Well the magnet came in today and I tried hovering it over those pickups as the incessant feedback drone filled the room and when I tried moving it closer (since it wasn't working) the magnet snapped to the pickups with such intensity that I flinched back as if a gun had gone off. Now you all can have no doubt that waving a magnet over pickups will not effect them in any significant way!

What electromagnets are you talking about?

Putting a strong neo magnet by the pickup's magnets can discharge them. So it's never a good idea unless you know what you are doing. We use neos to charge up alnicos and they can even recharge some ceramic magnets. But if you do it the wrong way, you can reduce the magnetic strength of the magnet in the pickup to pretty much nothing.

The issue here is these pickups were not wax potted. So that will likely fix the squealing issue.

[SonnyW]

If you like the tone, consider not f'ing with it

If they are anything like the Teisco pickups I have inspected, (which sound awesome!) they are very much a microphone.

Generally speaking:

A microphone is a moving coil in a stationary magnetic field.
An electric guitar pickup is a stationary coil in a moving magnetic field.
...The Teisco Gold foils are a combination of both.

Wax potting is the reason I have been able to take them apart and fix them I have also owned a few perfectly working teisco's and can tell you that the "moving coil" part is sensitive to near 5kHz. The "moving field" part has a corner frequency around 1kHz... Not very high!

Obviously by wax potting you will stop the coil from moving. Sort of like wax potting a SM57

Many of the Teisco guitars have the "pickups" labeled as "mic". They aren't kidding. Maybe your pickup isn't like a Teisco, so take my two cents with a grain of salt.

Cheers,
Ethan

IMHO Maybe this will help the OP. The top photo is a Teisco Gold Foil Pickup. I am only guessing but your pickup could be like this.




The next photo is IMHO what I would guess you might have if it isn't the top one, just from the few Zim Gar models I have seen.



IMHO Either one is a very microphonic pickup as Ethan said. And I agree it wouldn't be beneficial to pot them totally.
What I have noticed in the few that I have worked on is that the whole thing is just glued into the cover and sometimes the glue has gotten too old, and come loose which makes the whole thing loose and more microphonic, IMHO. I don't know if these are the ones you have but if they are then the first thing I would try is just to use a little hot glue to glue the thing back into the cover.

There were a couple of other styles of pickups, this doesn't cover the whole gamut.

[impaJah]

I just took some pics to give you guys a better idea. The cool thing about this guitar is the way you can switch to different pickups using these black switches. I was thinking I'd pot 2 or 3 of them and leave 1 or 2 unpotted and see how I liked that.

[SonnyW]

I just took some pics to give you guys a better idea. The cool thing about this guitar is the way you can switch to different pickups using these black switches. I was thinking I'd pot 2 or 3 of them and leave 1 or 2 unpotted and see how I liked that.

OK (IMHO) so this is the one you've got.



It is basically the exact same set of parts as the Gold foil model except the cover and that the ceramic magnet is on the bottom instead of having two magnets on the sides of the pickup (IMHO). The keeper, screws, and the coil are the same. This pickup is held together by gluing of the copper plated steel baseplate to the chrome cover. If you pot it you are going to have to either take it apart enough to get down to the coil only or risk warping the black plastic insert and possibly making a mess (IMHO). If you pot it I'd pot only the coil, but I still say that you shouldn't pot it at all it will likely kill the tone, which benefits from the microphonics. Of course that is entirely your choice. I'd say that you could put some more glue on the baseplate if it is loose. Some people are paying up to $100 each for the gold foil models and Ry Cooder can make them sing big time. I would think some about that before you put wax in there.

Also in my opinion the fact that the magnet was on the bottom and that it was a ceramic type is the only reason you didn't do some permanent harm by bringing a strong magnet close to it.

[FunkyKikuchiyo]

One thing that hasn't been mentioned yet is that you should closely inspect the pickup for loose parts. If anything is rattling around or not snug like it should be, it'll go crazy with microphonics. Even pickups that are very much prone to microphonics are completely fine at most volumes when working correctly. You may find that a solder joint broke or something that can be fixed easily and wax potting would be unnecessary. I'm going to guess by the look of the guitar you aren't playing it through a Triple Rectifier!

I'll defer to those who have had these apart on what could actually be wrong - I just wanted to throw that out there so you don't go into unnecessary surgery.

[impaJah]

Thanks for the input Sonny... very informative.

I mean I know potting these pickups is probably a travesty to some people, possibly yourself included, and so it's making me think twice. What I think I'll do is just pot one the way you're describing and see how it affects the tone and then decide whether it would be worth it to pot the rest.

Thank you all for the great advice and insight on this! I will give this thread an update when I pot the coil to let you all know how it turns out.

[SonnyW]

Thanks for the input Sonny... very informative.

I mean I know potting these pickups is probably a travesty to some people, possibly yourself included, and so it's making me think twice. What I think I'll do is just pot one the way you're describing and see how it affects the tone and then decide whether it would be worth it to pot the rest.

Thank you all for the great advice and insight on this! I will give this thread an update when I pot the coil to let you all know how it turns out.

FunkyKikuchiyo had a good input about the loose parts. It wouldn't be hard at all to take a look at the glue joints. I have seen a couple that were pretty loose and that can cause big time microphonics. Simple Titebond or Elmers glue can fix that if it is the problem. I'd say just do one pickup to start, if you are going to pot them. And if you do pot them I would use a double boiler and some kind of thermometer like a meat thermometer to keep the temperature of the wax under 150 degrees or so. Good luck getting down to the coils. It isn't easy. I used an exacto knife to cut the glue joint on the one in the photo. Also use some kind of glue like Titebond when you put it all back together to glue the keeper to the magnet and the baseplate to the cover. Loose parts just add up to more microphonics, cancelling the beneficial effect of the potting.

[impaJah]

I'm going to guess by the look of the guitar you aren't playing it through a Triple Rectifier!

I'll defer to those who have had these apart on what could actually be wrong - I just wanted to throw that out there so you don't go into unnecessary surgery.

Good info man. Actually I like a really heavily distorted guitar, I'm not exactly sure what a triple rectifier is but I'm guessing it's high distortion. You don't think it looks like a guitar someone would use to make sludge come out of their speaker?