Pickups that don't respond well to volume knob cleanup...any fixes?

[daz]

Chuck, i got the alnico 2 yesterday and tried them. So at this point A5 nor A2 seems to do what i want so tonite i plan to try what you said. I have done this before (with a 220k resistor on a switch) but only to change a pot's value so i could easily switch between them and see whether i like 250k or 500k pot best in a particular guitar. I didn't notice any different however in any way other than the difference the pot value gave. No change that i detected in resonant peak as i turned down or any difference in the bleed cap's affect.

Anyways, i plan to try it because you said it would at least in part keep the resonant peak from changing as i turn down, and thats exactly what i believe bothers me about these. When on 10 i actually like the tone a lot. But regardless of what treble bleed scenario i use and what value(s), as i turn down it seems like the pickup's inherent voice or EQ curve changes drastically. The sparkle in the highs goes away and some really dull sounding mid frequency that kills the attack on the wound strings starts becoming unbearable. In short, it just seems that on 10 it's a completely different pickup than 5 for example. Even turned down just to 8 it's already becoming dull. It's crazy, but it changes so radically that theres no treble left for the bleed cap to pass apparently because no value up to .001 that i have used retains any of the sparkly top as i turn down. The cap no matter the value never passes any treble higher than maybe 1k, if thats even considered treble ! More like hi mids. But thats all that gets passed no matter the cap value. Yet on 10 i get plenty of sparkly top end. Use a 250pf cap and put it on a pot and i can spin it from one end to the other with the guitar on 5 and hear no difference ! 500pf.....maybe a tiny bit.

So i'm totally unsure about how the theory behind this 1 M pot lowered to about 250k via a parallel resistor will keep this from happening, but at this point i'll try anything this simple if theres a chance. I'll let you know if it works. Thanks.

Daz,

I love me some big_teee. My own guitar is loaded with his pickups. I really don't want to squash his pitch here, but you did say "the pickup sounds fabulous". So I figure whatever you can do to avoid changing the tone you have now should be the first course of action.

I'm just guessing here, but it's possible that with the pickup setup as you have it, with the 3/3 arrangement on the coils, there is additional inductance that is disproportionate to the pickups actual output. It's a pickups electrical characteristics interacting with the load (volume pot) that makes guitars muddy when you back off the volume control. Since you may have an exacerbated version of this problem we can try to address just this first.

The circuit below should isolate the pickup somewhat from the action of the bright circuit as well as reduce the shifting of the pickup circuits resonant peak as the volume knob is backed down. With the knob up full the circuit will be electrically the same as what you have now.

I didn't include a capacitor value because I don't know what value you like for "bright" circuits. The impedance of this circuit is much higher than stock so you will probably need to use a cap value of half or even less compared to what you typically like. But experimenting is always encouraged.

[daz]

Ahhhh well, no joy. It just caused it to clean up the same but at a further point in the rotation. Worth a try but dang...

[Chuck H]

Well the series resistance has as much to do with it as the load. I'll work on another idea that uses a dual ganged pot and might be better. Do you think you can fit a dual ganged pot in the space?

I know you prefer to be a plug and play guy, but a low impedance preamp would almost certainly fix the issue. As would an active volume pedal instead of the guitar pot. If you love the guitar and you love the tone at full volume you might need to modify your usual MO to make it work.

[daz]

Well the series resistance has as much to do with it as the load. I'll work on another idea that uses a dual ganged pot and might be better. Do you think you can fit a dual ganged pot in the space?

I know you prefer to be a plug and play guy, but a low impedance preamp would almost certainly fix the issue. As would an active volume pedal instead of the guitar pot. If you love the guitar and you love the tone at full volume you might need to modify your usual MO to make it work.

Yeah, but i don't really wanna go there. If i need a preamp or such it;s like a bandaid on the issue. I like my guitars to work right as they are only having to maybe tweak each one a bit differently at the amp at most. No active or outboard stuff. Before i went there i'd try a more radical fix like a 2X regular size HB or single coil pickguard. Have a few other ideas too, but i'll exhaust all simpler possibilities first. I wouldn't even bother but i love this guitar too much side from the tone of the pups.

[big_teee]

So 3 north up A2 magnets on one bobbin, and 3 south up A2 magnets on the other bobbin?
A picture of the guitar body, & pickup setup would be nice.

[daz]

So 3 north up A2 magnets on one bobbin, and 3 south up A2 magnets on the other bobbin?
A picture of the guitar body, & pickup setup would be nice.

Yes, with each set of course on different strings. You have E B and G with north up and D A and E with south up on the other bobbin. I think i know where you're going, and i've thought of this kind of thing myself.....both the same (IE: north or south) but in parallel? or something along those lines?

[daz]

it looks like this. The screw polepieces are filled with north on one coil and south on the other. Each coil normally has 6 polepieces but the unseen ones are only accessible from the underside of the pickup. Those are now empty.

[big_teee]

That is a real nice guitar and setup.
I was curious if it used 2 or 4 height adjustment screws per pickup.
You could probably test a regular PAF style humbucker, temporarily, if it fits through the hole.
If you determine a regular pickup does fine?
You could try demagnetizing the A2 rod magnets some, on the Wide range pickups.
Rod magnets are a lot stronger at the string than steel slugs with a Alnico bar magnet under them.
Just throwing some ideas at you.
T

[Tom Phillips]

...a low impedance preamp would almost certainly fix the issue. As would an active volume pedal instead of the guitar pot. If you love the guitar and you love the tone at full volume you might need to modify your usual MO to make it work.

That is a good approach and there are additional ways to set up the topology. If your goal is to get the tone that you like then the approach worth considering.

... If i need a preamp or such it;s like a bandaid on the issue. I like my guitars to work right as they are only having to maybe tweak each one a bit differently at the amp at most. No active or outboard stuff...

Consider this...You have the guitar and then you have an amp. The guitar is passive and the amp is active. Unless you are going to play straight acoustic guitar there is no way to eliminate the "active" electronics. If you could get the tone you love by moving some of the active electronics to another location it seems worth considering.

For example, you could start by taking out the volume pot and loading the PUP with a parallel resistance. Experiment until you find the resistive loading value that produces the tone you like best. Next you add a single FET buffer and follow that with a pot set up as a volume control. The FET buffer has unity gain so it isn't really a "pre-amp" and it doesn't color the sound. It will isolate the pickup from the volume pot and allow different settings of the volume control without changing the loading on the pickup. By eliminating the change in loading the tone will not change as you roll back the volume. One additional tweak will be the capacitance loading of the PUP. With the FET buffer in place, the pup does not "see" the capacitance of the guitar cable. Therefore, to get the tone just right you may need to add a small amount of parallel capacitance in parallel with the load resistance between the pup and the FET buffer.

This approach does require that you add a battery in the Guitar to power the FET buffer but that seems a small price to pay if you can achieve your tone nirvana. Anyway, this is something to consider and, if you want to pursue it, we can link to some FET buffer discussions. If you don't want to put anything in the guitar then you can put the buffer in a volume control pedal as Chuck suggested. The guitar volume will then be left full up all the time.

What do you think?

Cheers,
Tom

[daz]

Like i was saying, I'd rather just go with a different type of pickup before I'd do anything like that. I was just fishing for a much simpler fix if someone happened to have one.

GFS now makes one too, and like all GFS pickups they're dirt cheap. $35 each or thereabouts. Same design....alnico bar, 12 screw polepieces. But mine are both 8k and thiers are 10.5k bridge and 7.5k neck. That tells me they are wound very different in one or more ways which may very well change that resonant peak i hate about these. Added bonus being much more balanced volume between the 2 unlike mine which goes from .22 rimfire on the bridge to WW3 on the neck. So i may try those and do the same alnico rod mod. Odds are the worse case scenario will be they end up being a little better. Maybe not worth $80 shipped but at least it wouldn't be a total loss. So i'm mulling it over.

That is a good approach and there are additional ways to set up the topology. If your goal is to get the tone that you like then the approach worth considering.

Consider this...You have the guitar and then you have an amp. The guitar is passive and the amp is active. Unless you are going to play straight acoustic guitar there is no way to eliminate the "active" electronics. If you could get the tone you love by moving some of the active electronics to another location it seems worth considering.

For example, you could start by taking out the volume pot and loading the PUP with a parallel resistance. Experiment until you find the resistive loading value that produces the tone you like best. Next you add a single FET buffer and follow that with a pot set up as a volume control. The FET buffer has unity gain so it isn't really a "pre-amp" and it doesn't color the sound. It will isolate the pickup from the volume pot and allow different settings of the volume control without changing the loading on the pickup. By eliminating the change in loading the tone will not change as you roll back the volume. One additional tweak will be the capacitance loading of the PUP. With the FET buffer in place, the pup does not "see" the capacitance of the guitar cable. Therefore, to get the tone just right you may need to add a small amount of parallel capacitance in parallel with the load resistance between the pup and the FET buffer.

This approach does require that you add a battery in the Guitar to power the FET buffer but that seems a small price to pay if you can achieve your tone nirvana. Anyway, this is something to consider and, if you want to pursue it, we can link to some FET buffer discussions. If you don't want to put anything in the guitar then you can put the buffer in a volume control pedal as Chuck suggested. The guitar volume will then be left full up all the time.

What do you think?

Cheers,
Tom

[robthequiet]

Edit -- So this is endemic to the WR pups in general -- Hm, just to toss out an issue so far not mentioned is the windings themselves. I'm not clear on whether or not the pickup has been a-b'd between guitars & vice-versa, but it sounds like you have good tone with the volume dimed, but the roll-off doesn't occur as expected, makes me think that there's some kind of inductance/impedance voodoo going on. I'm with the possibility of the wire gauge or winding technique being a factor. If it were my axe I'd probably just accept the tradeoff or get new pups, because it sounds like for all the tricks mentioned the fundamentals of the pup itself is the issue. What happens of you put it through a tube screamer, just for kicks?

[daz]

Edit -- So this is endemic to the WR pups in general -- Hm, just to toss out an issue so far not mentioned is the windings themselves. I'm not clear on whether or not the pickup has been a-b'd between guitars & vice-versa, but it sounds like you have good tone with the volume dimed, but the roll-off doesn't occur as expected, makes me think that there's some kind of inductance/impedance voodoo going on. I'm with the possibility of the wire gauge or winding technique being a factor. If it were my axe I'd probably just accept the tradeoff or get new pups, because it sounds like for all the tricks mentioned the fundamentals of the pup itself is the issue. What happens of you put it through a tube screamer, just for kicks?

It sounds fine thru any pedal with gain. Pedal or not, when you roll back the volume is where the issue is, pedal or just amp gain doesn't matter. If the volume on the guitar is down the issue surfaces. And yes, it IS a issue with all the fender reissue wide range humbuckers. My bet is on the windings also, which is why i am considering trying one of those GFS ones and doing the alnico rod mod to that. They are certainly wound different considering the bridge is 2 or 2.5k more resistance. So either a gauge difference or turn difference, but either way i imagine it's not going to have the same resonant peak as the fenders so that will almost surely be anywhere from a small to a huge improvement. By the way, i had one of these a few years back that was a '08 MIM, and it had the older version of fenders reissue wide ranges and the exact same issue with those. It's a known issue among many owners and the only ones that tend to like them are the guys who play with plenty of gain all the time and don't use the guitar volume to clean up. I even asked 2 guys who like them and thats exactly what they said they do. But as soon as you turn down in hopes of some cleaner chiminess the wound strings turn to mud. I now have it pretty close to being "fixed" but it's still there enough to nag me.

So why not get some aftermarkets? Because they are stupid expensive. The ones known to sound good start at about $400/pair. The very few cheaper offerings are questionable going by the reviews.

[rjb]

What you really need to do is measure how 'log' it is as in post #9. That's what governs how it reacts when turned down below '10'.

So far, we've heard that the volume pot worked great with other pickups in other guitars, and that its total resistance is 260 Kohm.

But we still haven't heard what the resistance is from wiper to outer lugs, when set at mid rotation.

Suggestion: Just for kicks, try a .01 uF treble bleed (with a known log-taper 250K pot) and see what happens.
Prediction: The pickup may actually get brighter as you drop volume.


EDIT:

Although I once owned not one, but two, Tele Customs (one with a factory-installed Bigsby), they're long gone and I didn't know technical details about WRHBs.

But if Wikipedia can be believed, WRHBs have larger coils than PAFs, and are wound with considerably more turns (~6800 vs ~5000).

So it would stand to reason that you've got a whole lotta inductance goin' on.

Hunch: You may be able to compensate by trying larger value treble bleeds than you typically use with "normal" pickups.

Or it might be a fun project to build and wind half-length DIY bobbins....

PS- Assuming bobbin size and wire gauge are the same, the 7.5K GFS neck pickup may get you closer to your goal.
But I would expect the hotter bridge pickup to have a lower resonant frequency and be even harder to "clean up".

[rjb]

It sounds fine thru any pedal with gain.

So, you have nothing against pedals per se- just active volume pedals?

[robthequiet]

So I guess what I would try would be a small value cap (.015uF to .022uF?) in series between the hot side of the pup and the volume, to shave some lows, possibly add a 5K resistor from the low end of the tone pot to ground, a la greasebucket, add a bit of high pass to offset? From what I'm reading around the net it seems that these pups were meant to keep some Fender twang with the beef and maybe the lack of cleanup is a side effect.