Potted vs. Unpotted: Harmonic content, Swirl, Openness, Pinch Harmonics

Zexcoil

Vendor
Messages
5,787
There's a measurable difference in the frequency response spectra of potted and unpotted pickups.

It's pretty subtle, but definitely there and it shows up in my pickups in features of the spectrum that are related to inter-coil coupling.

There's a slight shift in resonant frequency associated with the stuff I allude to above, and it's on the order of a capacitance shift equivalent to adding a couple of feet of quality cable to your chain.

I just had reason to revisit this recently and verified findings that I had made on this topic a few years ago.

Personally, and this is something that I can't attach hard data to - but I do believe it, I think these kinds of changes are much more significant when they are incorporated into the pickup itself, rather than downstream. That is, a couple/few 10's of pF introduced into the loop where the signal is being generated (i.e. between the windings) has a more significant effect on timbre than the same capacitance introduced downstream (i.e. by using a longer cable, for instance).

I don't generally wax pot my pickups. I do other things to control microphonics but it doesn't penetrate the windings.

I think "air" is a good qualitative adjective to describe the change in timbre between potting and not potting.
 

supergenius365

Silver Supporting Member
Messages
10,982
I just ordered some Zhangbuckers and David seems very anti-covers and potting (though he will do it). I am really looking forward to hearing these pickups. I have always had potted/covered humbuckers.
 

metropolis_4

Gold Supporting Member
Messages
5,718
the interesting thing is that none of those questions really matters to me;
i really enjoy playing my unpotted pickups.

i don't think about it so much in those kinds of "what does everyone else like?"-ways; playing, recording & my own musical experiences work for me.

i can deal with the squeal, so far; yeah, it's been years.

and, i have some potted pickups, too, but..... they sound & feel a bit dry to me, at this point..... which can also be useful, sometimes, of course.
That post was really only directed at Seth L and his comments. I didn't intend it as a general question to everyone.
 

metropolis_4

Gold Supporting Member
Messages
5,718
Because some people like way more gain than others?
But I thought you said that "good ones" don't have any issues with feedback or squeals? So gain shouldn't make any difference... ;)

You're the one who started this, and then stated that those of us who have trouble with squeals from unpotted pickups are either doing something wrong, or just don't use good enough gear so I'm not sure why you're pulling out the "just use whatever you like" card now.
 

Seth L

Senior Member
Messages
24,374
But I thought you said that "good ones" don't have any issues with feedback or squeals? So gain shouldn't make any difference... ;)

You're the one who started this, and then stated that those of us who have trouble with squeals from unpotted pickups are either doing something wrong, or just don't use good enough gear so I'm not sure why you're pulling out the "just use whatever you like" card now.
You said unpotted pickups were only for home use. I disagreed. I still do.
 

Seth L

Senior Member
Messages
24,374
Maybe if all I was doing was playing mellow clean tones at home levels I'd see the benefits of unpotted. But my experience has been they squeal like mad with nasty uncontrollable feedback at any real gig volume levels.
Just in case you forgot. I think you had a busted pickup.
 

jiml

Gold Supporting Member
Messages
11,089
If the covers not on properly, they'll squeal. Wolfetone players say you can stand 2 feet in front of a Marshall and they won't squeal. Basically, the good ones don't.
Hmmmm, I just got a Wolfetone Legend Ioaded Walsh LP. It squeals pretty easily in the bridge. I was going to pot it, kinda leery now....
 

metropolis_4

Gold Supporting Member
Messages
5,718
Just in case you forgot. I think you had a busted pickup.
What about all the other people who have posted having trouble with this same thing? Do we all have busted pickups? I don't remember you ever playing my guitar so it's funny you should know this.

Also, if you look at what I said, I never stated "unpotted pickups were only for home use". I said if I was only playing mellow clean tones at home levels I would see the benefits.

And finally, you continue to ignore any questions or comments about the things you've stated in here that apparently are difficult for you to defend.

I don't really see the point in continuing this do you? Can we just call it a day and move on?
 

Seth L

Senior Member
Messages
24,374
Hmmmm, I just got a Wolfetone Legend Ioaded Walsh LP. It squeals pretty easily in the bridge. I was going to pot it, kinda leery now....
I think you should contact the builder and see what he has to say.
 

metropolis_4

Gold Supporting Member
Messages
5,718
Hmmmm, I just got a Wolfetone Legend Ioaded Walsh LP. It squeals pretty easily in the bridge. I was going to pot it, kinda leery now....
It must not be a "good one", or you must not know how to properly install the cover, or you must just play metal with too much gain ;)
 

Seth L

Senior Member
Messages
24,374
What about all the other people who have posted having trouble with this same thing? Do we all have busted pickups? I don't remember you ever playing my guitar so it's funny you should know this.

Also, if you look at what I said, I never stated "unpotted pickups were only for home use". I said if I was only playing mellow clean tones at home levels I would see the benefits.

And finally, you continue to ignore any questions or comments about the things you've stated in here that apparently are difficult for you to defend.

I don't really see the point in continuing this do you? Can we just call it a day and move on?
I honestly thought you had a long time ago.
 

LARRY GERSHON

Silver Supporting Member
Messages
1,046
My potted Tom Holmes humbuckers in my real 62 Gibson Sg are some of the best sounding pickups I have heard and I have several other guitars with real early patent sticker humbuckers
 

Gary_

Member
Messages
272
The chap who built my pickups gave me the choice of potted, unpotted or partial pot. His take on it was that unpotted do sound better in terms of harmonics but are naturally more likely to feed back.

As stated earlier, I went unpotted and, as advertised, they did squeal the one time I played the guitar at gig volume (9 piece cover band with horn section).

He's a builder who knows exactly what he's doing and gave the correct advice - it's a guitar I wanted for studio use so the gig volume potential issue doesn't matter.... I tried it out of curiosity to see what it would do and he was right :)

Let's look at it this way..... We are all agreeing that unpotted sounds better aren't we? So, if there was no advantage to potting at all then no-one would do it.... The advantage is that, at gig volume, the lack of hassle you get outweighs the small sonic benefit in terms of harmonic content. For most people..... Some will like the ease of squealing and it's all good :)
 

Coldacre

Senior Member
Messages
9,839
I'm not buying this theory that all unpotted pickups squeal at "gig" volumes. my ReWinds don't squeal through my cranked AC30.

how on earth did Clapton, Page, Bloomfield, Green, Allman and basically every guitarists up until the mid 70's play gigs then?
 

edgewound

Member
Messages
5,725
If you play with high gain and/or the amp turned up to let the tubes unleash and you stand close to the amp or have stage monitors you're running through in close proximity to the pickups and you don't want microphonic feedback....squealing....you're gonna want potted pickups, unless you're so quick with the volume control to prevent it...which would be pretty tough.

All in all...it purely depends on your rig, how you play, pedals, gain, etc.

6 to 1, half-dozen to the other tradeoffs. I prefer potted pickups to not deal with squeal.
 

27sauce

Member
Messages
36,586
They don't all squeal. I play very loud at my regular gig, and 3 out of 5 of my gibsons are unpotted. None of them squeal. 2 vintage, one modern.
 

edgewound

Member
Messages
5,725
I'm not buying this theory that all unpotted pickups squeal at "gig" volumes. my ReWinds don't squeal through my cranked AC30.

how on earth did Clapton, Page, Bloomfield, Green, Allman and basically every guitarists up until the mid 70's play gigs then?
They stood 10-20 feet away from their amps.
 

edgewound

Member
Messages
5,725
I'm interested in hearing more about this partial pot....
Partial potting...Actually....the correct terminology is encapsulation. Potting is when components are sealed in goop or resin to prevent someone from easily reverse engineering a piece of equipment.

Partial encapsulation is a few dunks in wax to stabilize the outer windings from vibration.

Complete encapsulation is making sure all air is out of the windings to the core of the coil to make them stable and not get excited by electromagnetic stimulation causing microphonic feedback.

But....'potting' is quicker and easier to spell.
 

jiml

Gold Supporting Member
Messages
11,089
Wolfe told me to shave some wax off an unscented candle, soften them up with a heat gun and put them around the base of the pickup and cover. Heat again until the wax seeps into the pickup.
 




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