Dark humbuckers

[squeeze]

Hi folks

I have a guitar with dark / muddy passive humbuckers.
It has quirky electronics, with a battery-driven volume + equalizer boost circuit connected via of the push/pull knobs, and 250k pots.
Regardless of what setting I choose, it's either too dark / muffled in it's natural state, or too harsh / brittle in it's processed state.

Do you have any experience of modifying a guitar like this?

I'd like it to be naturally brighter, and was thinking of changing the pickups to another set of humbuckers using the same circuitry to see if that improves the tone, or converting it to humbucker-sized P-90s and bypassing all the fancy electronics.
I've also got single-coil guitars, so don't want something exactly the same as those.

What's the easiest mod to achieve the tone I want?

See attached for photos.
Thanks for your help.

[J M Fahey]

In principle wire one of them straight to output jack, with no other component connected to them, either active or passive, or just use a 250k-500k volume pot but nothing else.

Only then you will know its true sound.

Then test the other, same setup.

[squeeze]

In principle wire one of them straight to output jack, with no other component connected to them, either active or passive, or just use a 250k-500k volume pot but nothing else.

Only then you will know its true sound.

Then test the other, same setup.

Thanks for the idea. A simple test to see if the pickups are naturally dull. My other guitars are single-coil variants. I don't have any spare humbuckers around for comparison.

[tedmich]

Is this an EMG HZ setup? They made a BTC system with passive PU and battery driven boosts,
Some of these have dip switches which do treble cut etc, any tiny DIP switches ?

see here:https://www.emgpickups.com/pub/media...230-0204rd.pdf

[squeeze]

Is this an EMG HZ setup? They made a BTC system with passive PU and battery driven boosts,
Some of these have dip switches which do treble cut etc, any tiny DIP switches ?

see here:https://www.emgpickups.com/pub/media...230-0204rd.pdf

Hi, SD, not EMG pickups:

[Fluoroscope 5000]

The SD JB & PG models are pretty common, but you really should have 2 x 500k pots with them so the high-end isn't too rolled off. The (brass?) brackets around them also roll off more high-end. As for the active EQ, I think active systems usually have much lower pot values so the high end isn't too emphasized when it is engaged. Sounds like the guitar brand doesn't really know what they are doing, but supplied it with good PUP's and hardware. Perhaps the 250k pots were an attempt to make the split PUP sounds not too bright. I'd replace the vol & tone with decent 500K P/P pots. I got some CTS brand P/P pots that are very good. If it's still not bright enough in HB mode, you can replace the brass brackets with plastic. The active EQ is apparently a mid-cut/boost, so it shouldn't cause the brightness problem itself. Again it might need a low pot value in the ~25k range. Someone else might know about that.

[squeeze]

The SD JB & PG models are pretty common, but you really should have 2 x 500k pots with them so the high-end isn't too rolled off. The (brass?) brackets around them also roll off more high-end. As for the active EQ, I think active systems usually have much lower pot values so the high end isn't too emphasized when it is engaged. Sounds like the guitar brand doesn't really know what they are doing, but supplied it with good PUP's and hardware. Perhaps the 250k pots were an attempt to make the split PUP sounds not too bright. I'd replace the vol & tone with decent 500K P/P pots. I got some CTS brand P/P pots that are very good. If it's still not bright enough in HB mode, you can replace the brass brackets with plastic. The active EQ is apparently a mid-cut/boost, so it shouldn't cause the brightness problem itself. Again it might need a low pot value in the ~25k range. Someone else might know about that.

Thanks for your detailed advice. Much appreciated. I'll try swapping out the volume and tone pots for CTS 500k, and perhaps the pickup surrounds too.
I got this guitar back in 1992, and have mostly used it for high-gain stuff, which it does well.
As this was pre-internet days, it's difficult to find any tech info or wiring diagrams. I contacted Lag guitars months ago, but got no response - they just make acoustic guitars now.

[Fluoroscope 5000]

Thanks for your detailed advice. Much appreciated. I'll try swapping out the volume and tone pots for CTS 500k, and perhaps the pickup surrounds too.
I got this guitar back in 1992, and have mostly used it for high-gain stuff, which it does well.
As this was pre-internet days, it's difficult to find any tech info or wiring diagrams. I contacted Lag guitars months ago, but got no response - they just make acoustic guitars now.

Yeah, the current JB models are between 8~9H, so it will benefit the most from the higher pot values and should sound very good in parallel mode at 2~2.25H as well. The PG neck is apparently only ~4H, so it might sound a bit thin in split mode. Not sure if split mode is parallel or just shorting one coil, so that will affect the split sound a lot.

I assume the EQ and its pot is completely out of the circuit when not engaged? Again, I don't know how that pot value or the others affect the tone when the EQ is engaged. GFS sells some active EQ kits that might offer some pointers for you. They are cheap enough that it might be worth buying one just for the installation instructions, or that the newer/different circuitry might just sound better. 9V-powered OpAmps weren't very good quality until fairly recently.

Another option would be to replace the EQ circuit with a passive Wilde "Q-Filter" which would just offer a variable midrange dip with high-end extension as you turn the knob down. I have one myself. You'd still want a 500k P/P pot for that, and then wire it to switch over from the tone knob and when you pull the pot up. It may be a bit redundant with the coil splits and all, but it will offer more precise control over the mid-dip tone per pickup setting.

Make sure you use a low enough wattage and proper technique iron so you don't burn out the new pots. It's also worth using flux on the back of the new pots and contacting the iron to a rear edge/corner so you can easily build up some solder. Then tin any wires going to it and solder them all at once to the solder "pool".

[tedmich]

so pot not strong enough = weak highs, got it.

[freefrog]

Hi folks

I have a guitar with dark / muddy passive humbuckers.
It has quirky electronics, with a battery-driven volume + equalizer boost circuit connected via of the push/pull knobs, and 250k pots.
Regardless of what setting I choose, it's either too dark / muffled in it's natural state, or too harsh / brittle in it's processed state.

Do you have any experience of modifying a guitar like this?

I'd like it to be naturally brighter, and was thinking of changing the pickups to another set of humbuckers using the same circuitry to see if that improves the tone, or converting it to humbucker-sized P-90s and bypassing all the fancy electronics.
I've also got single-coil guitars, so don't want something exactly the same as those.

What's the easiest mod to achieve the tone I want?

See attached for photos.
Thanks for your help.

Ah, LAG guitars... I was often playing their first models in guitar shops in the early 80's and wished I had enough money to buy one. :-)

To answer precisely to your request:

-the too bright tone when the preamp is enabled might be fixed by a low value cap between hot and ground of the pickup (on the passive side, "before" the preamp), integrated to the switchable part of the circuit: something between 470pF and 1.2nF should do the job by sweetening the sound like a long cable would do with passive electronics (the Jackson preamp of my old Charvel CH4 hosts a 1nF cap for that if memory serves me). Try lower or higher capacitive values if needed, knowing that 1m of cable is emulated by 100 to 150pF;

-with passive electronics: a 500k or 1M volume pot + a no load tone control should do the job (knowing that a no load pot is easy to obtain from a regular pot after a bit of tinkering)... paired if necessary with a short / low capacitance cable: see Sommer LLX (not XXL), which exhibits the lowest capacitance on the market without being expensive... it would/will shift up the resonant peak of the JB, making it sound brighter.
...or connect the non used end of the tone control to a "Q filter" as recommended by Fluoroscope 5000 (knowing that a Q filter can be bought or home made: it's just a low DCR inductor, after all)... unless you pair your bridge PU with a dummy coil/inductor wired in parallel, in order to "tune" its inductance... even an old or cheap "hot" humbucker deprived of its baseplate and magnet can be used for that: a 16k/8H cheapo HB without its ceramic mag (but keeping its slugs and screw poles in the coils) should do a decent job by reducing measured specs to "P..A.F. alike" values of 8k/4H approximatively (as long as the resistive controls are not 250k ones: 500k or 1M controls should compensate the "inertia" of any dummy coil in parallel... and setting the pickup closer to the strings should cure the related loss of output level if needed: in bridge position, no real risks of detrimental magnetic interactions).
Or wire your JB itself in parallel, simply: it's drastic but would give the same kind of inductance than a Filter'Tron so it's not unuseable.
I generally avoid to recommend series capacitors because they bring problems when wired between pickups and tone controls (and give a "banjo tone" in some cases when the series capacitive filtering is overdone) but it's still another way to reEQ a dark/hot bridge PU.

HTH... I've a first hand experience with all these tricks and that's why I evoke them. Feel free to PM me for more explanations if necessary.

Good luck in your quest! :-)

[Fluoroscope 5000]

Ah, LAG guitars... I was often playing their first models in guitar shops in the early 80's and wished I had enough money to buy one. :-)

To answer precisely to your request:

-the too bright tone when the preamp is enabled might be fixed by a low value cap between hot and ground of the pickup (on the passive side, "before" the preamp), integrated to the switchable part of the circuit: something between 470pF and 1.2nF should do the job by sweetening the sound like a long cable would do with passive electronics (the Jackson preamp of my old Charvel CH4 hosts a 1nF cap for that if memory serves me). Try lower or higher capacitive values if needed, knowing that 1m of cable is emulated by 100 to 150pF;

-with passive electronics: a 500k or 1M volume pot + a no load tone control should do the job (knowing that a no load pot is easy to obtain from a regular pot after a bit of tinkering)... paired if necessary with a short / low capacitance cable: see Sommer LLX (not XXL), which exhibits the lowest capacitance on the market without being expensive... it would/will shift up the resonant peak of the JB, making it sound brighter.
...or connect the non used end of the tone control to a "Q filter" as recommended by Fluoroscope 5000 (knowing that a Q filter can be bought or home made: it's just a low DCR inductor, after all)... unless you pair your bridge PU with a dummy coil/inductor wired in parallel, in order to "tune" its inductance... even an old or cheap "hot" humbucker deprived of its baseplate and magnet can be used for that: a 16k/8H cheapo HB without its ceramic mag (but keeping its slugs and screw poles in the coils) should do a decent job by reducing measured specs to "P..A.F. alike" values of 8k/4H approximatively (as long as the resistive controls are not 250k ones: 500k or 1M controls should compensate the "inertia" of any dummy coil in parallel... and setting the pickup closer to the strings should cure the related loss of output level if needed: in bridge position, no real risks of detrimental magnetic interactions).
Or wire your JB itself in parallel, simply: it's drastic but would give the same kind of inductance than a Filter'Tron so it's not unuseable.
I generally avoid to recommend series capacitors because they bring problems when wired between pickups and tone controls (and give a "banjo tone" in some cases when the series capacitive filtering is overdone) but it's still another way to reEQ a dark/hot bridge PU.

HTH... I've a first hand experience with all these tricks and that's why I evoke them. Feel free to PM me for more explanations if necessary.

Good luck in your quest! :-)

Interesting ideas there. Wiring a cap over to ground b4 the active EQ should actually bring up the upper-mids a bit, more so on the lower inductance pickup settings so it might not solve the issue. I'd seriously consider replacing the EQ with a newer better quality one, or maybe the passive Q-Filter. Here's some info on the Q-Filter: https://guitarnuts2.proboards.com/th...scrollTo=99583

Replacing just the Volume pot with a 500K or 1M pot might be enough, but he might as well order two 500k CTS P/P pots just in case. Don't you think? They aren't expensive. I agree with getting a 10-15' Sommer LLX cable. I just got 10' with some noiseless HICON plugs and it's great, but that won't necessarily make the JB sound brighter. In fact, a low C cable will reduce the level of the resonance peak so it sounds a bit smoother, albeit with a more extended high end. Either way, all pickup settings should sound well clear enough with 500k pots.

Yes, the JB should sound great in parallel mode. You might consider wiring the "split" mode for it that way if it isn't already. Wiring the PG PUP to short one coil might be preferable to parallel mode if you don't mind the hum. Just make sure the shorted coil is fully out of the circuit so it doesn't load down the active coil.

A series wired capacitor just rolls off some bass. 500k pots will bring back the highs. The Brass mounts might even keep the lower inductance settings from sounding too bright, and the low capacitance cable will round off the resonance peaks while extending the high end for acoustic guitar-like split and combined PUP tones. Sounds like a plan.

[freefrog]

Interesting ideas there. Wiring a cap over to ground b4 the active EQ should actually bring up the upper-mids a bit, more so on the lower inductance pickup settings so it might not solve the issue. I'd seriously consider replacing it with a newer better quality one, or maybe the passive Q-Filter. Here's some info on the Q-Filter: https://guitarnuts2.proboards.com/th...scrollTo=99583

Replacing just the Volume pot with a 500K or 1M pot might be enough, but he might as well order two 500k CTS P/P pots just in case. Don't you think? They aren't expensive. I agree with getting a 10-15' Sommer LLX cable. I just got 10' with some noiseless HICON plugs and it's great, but that won't necessarily make the JB sound brighter. In fact, a low C cable will reduce the level of the resonance peak so it sounds a bit smoother, albeit with a more extended high end. Either way, all pickup settings should sound well clear enough with 500k pots.

Yes, the JB should sound great in parallel mode. You might consider wiring the "split" mode for it that way if it isn't already. Wiring the PG PUP to short one coil might be preferable to parallel mode if you don't mind the hum. Just make sure the shorted coil is fully out of the circuit so it doesn't load down the active coil.

A series wired capacitor just rolls off some bass. 500k pots will bring back the highs. The Brass mounts might even keep the lower inductance settings from sounding too bright, and the low capacitance cable will round off the resonance peaks while extending the high end for acoustic guitar-like split and combined PUP tones. Sounds like a plan.

Hello,

To answer to your "Don't you think?" : I humbly think that the efficience of "electronical fine tuning" narrowly depends on the guitar used (and on the rig involved). That's precisely why I've tried to share a wide palate of possible solutions - knowing that all of them won't necessarily work equally well with the mentioned guitar but remembering also that each of the tricks that I evoke has been useful to me one or several times these last 40 years. I wouldn't had wasted our time if it wasn't the case. :-)

That said, I hear you: for example, what you say about the smoother tone when the Rz shifts up is more or less something that I was evoking years ago on MLP.

Regarding Q filters: I've the highest respect for Bill Lawrence (RIP) and wouldn't hesitate a second to recommend his products. Now, I've toyed with such inductive filters for decades (and have built my own custom made Q filters, according to the inductive effect desired). On the basis of this subjective experience, I tend to think that "official" Q filters are not the only possible or intestesting solution: there's a world to explore there, IME and IMHO, and one man's trash can be another man's gold. ;-)
But I don't want to pollute this topic and my goal was just to help squeeze so I'll just shut my mouth now. :-))

[Fluoroscope 5000]

Hello,

To answer to your "Don't you think?" : I humbly think that the efficience of "electronical fine tuning" narrowly depends on the guitar used (and on the rig involved). That's precisely why I've tried to share a wide palate of possible solutions - knowing that all of them won't necessarily work equally well with the mentioned guitar but remembering also that each of the tricks that I evoke has been useful to me one or several times these last 40 years. I wouldn't had wasted our time if it wasn't the case. :-)

That said, I hear you: for example, what you say about the smoother tone when the Rz shifts up is more or less something that I was evoking years ago on MLP.

Regarding Q filters: I've the highest respect for Bill Lawrence (RIP) and wouldn't hesitate a second to recommend his products. Now, I've toyed with such inductive filters for decades (and have built my own custom made Q filters, according to the inductive effect desired). On the basis of this subjective experience, I tend to think that "official" Q filters are not the only possible or intestesting solution: there's a world to explore there, IME and IMHO, and one man's trash can be another man's gold. ;-)
But I don't want to pollute this topic and my goal was just to help squeeze so I'll just shut my mouth now. :-))

I follow you. We can't really predict how any of our recomendations will sound in the guitar. After reconsidering that the Fe pickup core combined with the Brass brackets will likely drop the output at least 1dB by 2.5kHz on the JB, it actually might be better with a typical medium C cable in the 350~400pF range. That should increase the peak by ~1dB and shift it down to where the other two factors will have less effect. There should then be at least a 1dB peak just above 2kHz (with 500k pots into a 1M preamp input), and there will be progressively more high end damping from the Brass brackets useful for the very low inductance settings.

[Helmholtz]

I don't think the brass mounts can have a noticeable effect in HB mode, because the Eddy currents induced by the 2 coils run in opposite directions and should essentially cancel.

Some info here: http://kenwillmott.com/blog/wp-conte...r_Geometry.pdf

[Fluoroscope 5000]

I don't think the brass mounts can have a noticeable effect in HB mode, because the Eddy currents induced by the 2 coils run in opposite directions and should essentially cancel.

Some info here: http://kenwillmott.com/blog/wp-conte...r_Geometry.pdf

If that's the case then there'd be even less reason to use 1M for one of the pots. My guess is the guitar will surely be bright enough with 500k pots the Maple Neck/Ebony FB and thick Steel saddles.