[marcwormjim]

The updated Charvel Guthrie Govan has a switch for "single coil simulation" that is speculated to be borrowed from the S-1 function on his 2013 Jazzmaster Select. According to Fender, the switch basically routes the leads of the humbuckers' inner-coils through a "resistor/capacitor" combo without breaking the series wiring - Essentially, it filters the humbucker, but only one coil is being filtered. The result is a single coil-simulation with no drop in volume.

Can anyone shine some light on this? I really want to mod my HH and HSH guitars with this, to avoid the signal-dropout that comes with split or parallel-switching.

[darkbluemurder]

I am not sure how they do this exactly but I have seen a few variants to this theme:

- standard coil splitting is to ground the series connection of the humbucker coils
- Bill Lawrence preferred to insert a 0.022uf cap between the series connection of the coils and ground. What this does is that the coil is not shunted off completely - only the highs get shunted above the knee frequency of the cap, everything else stays unaffected. Positive side effect is that the hum cancelling ability is maintained. I have used caps as high as 0.047uf with good results. The bigger the cap the closer you get to the true split - however, the signal drop out increases as well. With a 0.022uf the signal drop out is not noticeable.
- PRS used resistors in place of the cap in their DGT guitars (1.1k for the neck pickup, 2.2k for the bridge pickup). What this does is more difficult to describe. It is not so much a tone thing even though I think it takes away a bit of the harshness of the single coil tone but more of a feel thing in a way that the guitar appears to play easier. Humcancelling ability is lost, however, and so is signal strength.

So the Charvel method may be a combination of the Lawrence and PRS methods. So if your goal is to avoid signal drop out, start with the Lawrence method unless we hear from somebody that has one of these guitars on the bench and can check what's in there.

Cheers Stephan

[marcwormjim]

Thanks. I was vaguely aware of both, but hadn't thought of combining them in that way.

[marcwormjim]

A helpful gentleman on ss.org had previously asked Fender, and was told that it's a coil split in which the inner coil signal is put through a .1uf cap and a 1.5k resistor in series along the shunt to ground.

[darkbluemurder]

Many thanks for posting this - so I was not that far off.

Cheers Stephan

[marcwormjim]

Bump.

I made this mod to one of my Parker Flys.

First-off, you still get hum. I assume this is because, though both coils are still active and in-series, you've unbalanced the resistance.

The way I see it is: The typical way of grounding a coil to "split" a humbucker gives you a single coil-sound, along with hum and a drop in output. Putting the coils in parallel is the most common compromise between the two: You get twang, and a drop in output (though not as severe as grounding a coil), but retain the hum-canceling.

This mod covers the other base: You get the twang and hum, but a negligible drop in perceived output. The input meter showed a drop in the Air Zone and Air Norton when the filter was engaged, but I wasn't hearing anything but the frequency scoop.

It also seems that the C/Ω values could stand to be tailored for the character of each pickup. This would explain why this mod remains largely unknown.

I have two Flys, each with an aired Tone Zone, and wired with a push-pull tone pot for splitting. One guitar grounds the inside coils (for spankier tones from the outside coils), and the other grounds the outside coils (I've found the inside coils higher in output; and appreciate the smaller drop in signal).

I made the mod to the Fly that normally grounds the inside-coils. As expected, the filtered humbucker is hotter than grounding the outside-coils, and of course sounds less-authentic in its single coil-simulation.

Essentially, I view this as a "voice" option for a humbucker, rather than a mod aiming for an authentic single coil-sound. Also, experimenting with different values should scoop the pronounced mids of the Air Zone/Norton combo to a more dramatic extent.

I am exactly the target consumer for this mod; as I prefer lower output-humbuckers, but have always hated that you necessarily end up with an unusably weak split tone. This limits my options to using a hotter humbucker than I'd like, just for the sake of a usable split tone, or else just taking the guitar off and grabbing one with single-coils.

I'm waiting on a set of customs from Artec (Basically '59-style PAFs with alnico 5s, double-screws, and scatterwound just to see if I hear a difference). The guitar I put them in will receive the same mod. Any differences I notice between them and the Air Zone/Norton will be mentioned in this thread.

[marcwormjim]

April Bump.

Glad to say using this mod with the Artecs gave me the results I wanted: Filtering low-output humbuckers yields single-coil sounds without the drastic drop in output.

Of note is that you get a more dramatic difference in voicings the closer the poles of the unfiltered coil are to the strings: Setting coil/pole piece height is essential in dialing in the "strattyness" of the filtered tone.

Another thought is that this mod works best with brighter humbuckers. I'm running these PAFs through a 500k volume and 250k tone; and the subdued highs of the humbuckers (of course) remain in the filtered tone. I suspect those of us accustomed to the change in resonant peak and perception of higher highs and lower lows in coil-splitting feel cheated when this mod effectively only filters the mid-frequencies to achieve that snap and twang. I suggest anyone performing this mod use 500k pots-only.

[marcwormjim]

Jan ‘18 bump.

Now that I own a Charvel Govan, I can say with certainty that the guitar’s “single coil simulation” is achieved by having a .1uf metal polyester film cap along each shunted series connection’s path to ground (Charvel uses two identical caps - One for each humbucker). No resistor.

They’re Illinois Capacitor brand, stamped with

ic msr 104k 250v

I must say, I prefer the effect of the added 1.5k resistor, due to it yielding a more authentic single coil sound to go along with the bigger drop in output.

Let’s say (for illustration) that a typical coil split decreases a humbucker’s output by 50%, and yields the most authentic single coil sound. By putting a .1uf cap and 1.5k resistor in parallel (as in a treble bleed) between the series connection and ground, you lose only around 25% output, and have a proportionally less-authentic single coil emulation. By using only the cap with no resistor, the effect is far more subtle (akin to turning a treble bleed volume pot down) - I would guesstimate around a 15% drop in volume.

As stated in a previous post, the effects are best observed in a low-output humbucker. The filter I previously installed for use with an Air Norton/Tone Zone combo yielded spank, but I ultimately found the results less satisfying than a true split (which I’m currently using with a Gravity Storm set I put in the same guitar). I was similarly unhappy with a medium-output set, before finally being happy with the way a low-output set (with a high resonant peak) had its drop in output mitigated by the mod.

[darkbluemurder]

Many thanks for the updates.

Putting the series connection to ground via a .1uf cap is basically a variation of the Bill Lawrence version. It seems that they wanted a single coil tone without the hum. In my experiments I found .047uf already low enough to kill most of the hum and still sound single coil-ish. I agree that the cap and resistor values should be tuned to the pickup they are being used with. For low output humbuckers a change in the voicing may be enough while for higher output pickups a reduction in output could be welcome.

Good luck with your experiments,
Stephan