Insulating baseplates with tape : why I find it discussible, finally.

[ScottA]

You can't quantify tone? Or is it that you don't want to figure out how to do so?

I'll certainly agree that there's a lot more to the tonal effects that a pickup imposes upon the characteristics of a vibrating string (and the instrument on which it is mounted) than the resonant frequency, Q, and low end roll off of a pickup coil, but those are valid measurements that certainly quantify some of the tone shaping. As for the rest, just because we don't seem to have adequate and agreed upon measuring systems yet doesn't mean that we might not in the future.

I think the characteristics of the pickup as a filter are more complex and more important than you give them credit for (based on some of your other recent posts, in addition to this one), but I agree with your sentiment whole-heartedly!

[rhgwynn]

Maybe quantify was the wrong word to use; since there is no "quantity" to be measured. I guess we aren't counting apples here. I'll come back and edit my post after I get me some more wordy word learnin from teacher. I am glad to see that my intent was not lost on some of you. But anyway, although sound and tone are extremely subjective - there are absolutes, that can be measured and given a value. Once we are able to correlate those values with the changes we perceive and actually understand where those changes come from, it will be a game changer. Some of us have already made great inroads into this mysterious territory. It's almost like, removing the subjectivity of it all. I mean, we all have our preferences; but if one coil has some serious sag in a crucial frequency, then it may one day be possible to be able to say irrefutably exactly why that happened. Rather than just thinking "that sounds weird," cutting the coil off, and rebuilding.

[Rick Turner]

I do not discount the effect of the RLC filter effects in high impedance pickups at all. I guess I was just fortunate to start my pickup making career at the lower end of the impedance scale, and so I got used to hearing things that tend to be masked by what HiZ pickups do. I'm just not so coil-centric as many are. I want to hear stuff coming from a relatively flat audio-spectrum point of reference. Then I can choose to super-impose coil filtration...or not.

Actually, a lot of what I currently wind are high impedance pickups...to some pretty high DCR levels...like 10 K plus on each coil. And I'm winding with pretty small wire...44 ga. But I'm not trying to emulate any pickups, and I do use on-board preamps a lot. I like this combo of HiZ pickup and then preamping it. It's kind of in another direction, but it works, at least for me and my customers.

[David Schwab]

I'm not sure either of what it did but I'm sure of my statements: it caused the Q factor to be slightly higher and it definitively tamed the squeal under high gain. :-)

AFAIK, BK lacquers the mags of their humbuckers for the same reason. https://bareknucklepickups.co.uk/main/howwemakethem.php ("Potting" section).

A winder who is member here has also said once that slugs touching the baseplate could generate noise: Unpotted pups and covers. - MyLesPaul.com (post 9).

FWIW.

Oh, and... thx for the reminder about the reasons to ground the poles.

If the baseplate can vibrate against the slugs, you will get noise. That makes sense. Same with putting a metal cover on, which is why they often put some wax in them.

Lacquer the magnets? I don't buy that for a minute. Case in point, they lacquer some cymbals. If it changes the tone it's by a minuscule amount. Putting lacquer on a magnet is not he same as potting it. You might want to try putting some epoxy on the bottom of the pickup to make the whole thing solid.

[David Schwab]

You can't quantify tone. It is possible to plot a resonant peak on a graph, but there is no measurement for the sound perceived.

I'll have to disagree here. What's the difference between a Strat pickup and a typical humbucker? The dominant difference is the resonant peak is at a lower frequency on the humbucker. There are other differences, but that one right there can se the tone.

This is easy to test by taking a pickup with an extended high frequency response and using a low pass filter with variable Q to add the resonant peak in. Or, take a bright single coil and EQ it, kind of like the way the EMG SPC does, or the RPC with a humbucker. Or even using caps to roll off low end can make a humbucker sound a lot like a single coil.

So the point is that how the pickup shapes the tone is what define's its tone. The fact that we can plot it on a graph shows that.

[Rick Turner]

Got to jump in with my non-coil-centric view of single coil (let's just settle on Strat for the sake of this discussion) and Gibson-style humbucker. The aperture and general shape of the magnetic fields are very different. Someone may have done this, but try winding a humbucker so the resonant frequency is the same as a Strat pickup...yeah, yeah, the inductance is different, the height of the peak is different...but get close. Now listen. Or go back to my much earlier suggestion...wind each to low/medium impedance...low enough so the resonant frequency is at 25 kHz or so. Now listen. These two pickups absolutely do NOT sound the same. So more than the coil shapes the signature tone of a magnetic pickup.

I'm just amazed that fewer folks have actually tried this. I don't think you can understand pickup tone until you do.

And yes, any metal that can vibrate in the magnetic field...slugs, bars, pickup mounts, pickup covers...it's audible.

I stopped potting my pickups in metal covers because even with wax potted coils and then epoxy potted everything, the nickel silver covered pickups would squeal at high gain levels. Now I paint the inside of plastic covers with Electrodag for shielding. Works just great. Haven't tried to measure eddy current loss but I bet it's a hell of a lot less with a very thin layer of conductive paint than with either foil or a full metal jacket.

BTW, there are schemes by which you can do Faraday cage screening with minimal eddy current loss. You could do it on PC cards, for that matter, or even use low-eddy, Faraday shield PC cards for pickup bobbins and flexible circuit boards around the perimeter. Frank?

[Rick Turner]

FWIW, when I was working for Gibson I got to spend a bit of time with Bill Lawrence...a real character, to say the least. He claimed that one of the degrades to the original PAF design was going to plastic spacers under the coils rather than the original maple. His reasoning was how the plastic could hold an electrostatic charge differently than the wood. T or F? I don't know, but it was part of returning to as original spec making as he could get them to do.

Do any modern Gibson pickups get any respect? Or Fender? I don't know that, either; I'm just away from that whole market segment. I did find it incredibly amusing when Seymour was selling Tele pickups to Fender and humbuckers to Gibson... Just goes to show you that if you ever get a reputation for cheapening your product (making less expensive to produce can be OK...but not cheapening), you'll pay the price long after you try to recover the mojo.

Rickenbacker, anyone?

[Rick Turner]

One other comment and kind of back to the OP issue. Even the thickness and durometer of tape used this way will likely affect something audible. Kind of like how different folks like different wax formulas for potting. I tape around my magnets with Kapton and like it just fine. For one thing, there are no issues with heat in the wax potting stage.

[David King]

Rick, Perhaps some clarification on the Electrodag paint? They make products with copper, nickel or silver among others.

[Rick Turner]

David,

I'm just using the simple carbon stuff from StewMac. I just don't see the need for anything more exotic.

But...I am using the tin plated copper foil tape with the conductive adhesive by 3M which is a bit more exotic than straight ahead copper. It looks better, and it's tinned so it solders easier. You can get custom widths slit pretty easily. I use it when I'm in a hurry, for ground "drain lines" under the conductive paint, etc.

[John_H]

You can't quantify tone? Or is it that you don't want to figure out how to do so?

I'll certainly agree that there's a lot more to the tonal effects that a pickup imposes upon the characteristics of a vibrating string (and the instrument on which it is mounted) than the resonant frequency, Q, and low end roll off of a pickup coil, but those are valid measurements that certainly quantify some of the tone shaping. As for the rest, just because we don't seem to have adequate and agreed upon measuring systems yet doesn't mean that we might not in the future.

I'm working on the design of a universal test fixture that will allow great repeatability testing pickups with vibrating strings. It will be highly controlled, monitored at both string ends by extremely accurate piezo "reference" pickups, and should be able to clear up some of the mysteries around the "tone" of a pickup under real world conditions...with strings, not a signal coil. More to follow.

Certainly there are many things that you can assign values to, and these can be helpful tools. Yes, and maybe someday soon technology may allow us to take a multidimensional measurement for units of tone. Until then we can use these tools to help predict the characteristics of the tone much the same way a chef may predict the flavor of a certain dish that he's preparing, and just like the taste you perceive can't be measured, for now neither can the tone you hear. In the future they'll program this data into the discreet one per string digital sound processors on the self tuning guitars so that with the simple flick of a switch you can sound like jimi, eddie, or stevie. Until then we'll mostly have to rely on our ears.

Chasing some of this small data to me seems almost like dissecting a paint brush.

[Rick Turner]

The future is sooner than you may think it will be. In fact, some of it has already passed in the work I've done... Getting into DSP acoustic guitar modeling taught me in incredible amount about how acoustic guitars actually work, for instance. It's all about point of view. Try to get away from the familiar point of view (while never dismissing it entirely), and you may find new ways to hear, to understand, and then to design.

And some of what you think of as being small data may be of the greatest importance. I remember a time before slew rate was understood to be more important than THD when correlating subjective impressions of amplifiers to objective measurements. Then in about 1970, a new day was understood.

I think that's how it may be with the understanding of what makes pickups "sound" as they do. The coil stuff is easy to measure right now, but it just doesn't tell the whole story...at all.

[rhgwynn]

The future is sooner than you may think it will be. In fact, some of it has already passed in the work I've done... Getting into DSP acoustic guitar modeling taught me in incredible amount about how acoustic guitars actually work, for instance. It's all about point of view. Try to get away from the familiar point of view (while never dismissing it entirely), and you may find new ways to hear, to understand, and then to design.

What amazes me about acoustic guitars, is how they and produce such a wide range of tones; as well as how that sound can further be varied simply by your location within it's sound field. Microphone or pickup placement can make the difference between poor and stellar tone; as well as how your audience is positioned. With no mic at all, every single person in front and behind you, including yourself - is getting a different experience when they hear you play. I can only imagine that creating a believable acoustic DSP model must be quite difficult.

[Rick Turner]

And then there's the room...

That is/was the next frontier I wanted to explore with the D-TAR Mama Bear algorithm project. I still hear too much small room reflection in our algorithms. Never got the chance to do the sample recording in either a big anechoic chamber or a very large room with long first reflections.

Acoustic guitar tone doesn't come into it's own until you get back about five feet away from the guitar itself, and then you're usually getting an unfavorable ratio of room to guitar in too many situations. If you want to hear acoustic instruments recorded at their best, listen to any Water Lily Acoustics CD's or vinyl. Incredible. Many were done direct to a 1" two track in Blumlein stereo with the mics about five feet away from the musicians in a very large church. The direct to reflected sound ratio is the best I've ever heard...just enough ambiance, but with no loss of the clarity of the direct sound. Too many of the ECM recordings are too ambient.

There is a lot about acoustic guitar that informs my approach to electric guitar; yeah, it's yet another way to listen.

[John_H]

The future is sooner than you may think it will be. In fact, some of it has already passed in the work I've done... Getting into DSP acoustic guitar modeling taught me in incredible amount about how acoustic guitars actually work, for instance. It's all about point of view. Try to get away from the familiar point of view (while never dismissing it entirely), and you may find new ways to hear, to understand, and then to design.

And some of what you think of as being small data may be of the greatest importance. I remember a time before slew rate was understood to be more important than THD when correlating subjective impressions of amplifiers to objective measurements. Then in about 1970, a new day was understood.

I think that's how it may be with the understanding of what makes pickups "sound" as they do. The coil stuff is easy to measure right now, but it just doesn't tell the whole story...at all.

Thanks for the reply Rick, and my apologies to the OP for the hijack.
The future is definitely upon us. I think I'm amazed and afraid at the same time nowadays. The technology today is fascinating. It has put tools in to peoples hands that only a generation ago would have been unimaginable, yet people are using them to replicate decade's old analog signals. That's like the tail wagging the dog.

I do get it though. The better the data is, the better your sim/modeler can be. I've heard recordings of amp sims where I couldn't tell the difference. I should broaden my perspective a little. I can be pretty narrow minded at times.