Wiring Dilemma: Epiphone Wildkat Diagram vs. Gretsch 5120 Diagram??

[Watermark]

Greetings to All,

I'm currently working on an Epiphone Wildkat that I've recently equipped with two new P90s, but the original wiring including all pots, switches, jacks, etc., have been removed and replaced, so I could seriously use some help selecting the best overall (i.e., proper) wiring diagram for it.

For discussion purposes, the Epiphone Wildkat has eight (8) electronic components as follows: two pickups (NP/BP), two volume pots (NV/BV), a Master Volume (MV), Master Tone (MT), 3-Way Switch (SW), and Output Jack (OJ). And according to available Epiphone records, the wiring should be done as seen in the attached file labelled "Epiphone Diagram". However, Gretsch series 5000 guitars (5120 etc.) have the very same eight (8) electronic components as the Epiphone Wildkat, yet their suggested wiring diagram completely differs from the Epiphone. [Please see the attached two wiring diagrams labelled "Epiphone Diagram" and "Gretsch Diagram" for reference, and pay particular attention to the major differences between the two in terms of connections at the Master Volume (MV) and Master Tone (MT) pots.]

Now, given the fact that both guitars use the very same eight components, my question is this . . . how and why do they utilize completely different wiring schemes, and which is likely to offer the best, most versatile performance in terms of overall function and tonal variation? I ask this largely because its an arch-top, with limited spatial access to all of these various components, so gutting it multiple times without clear direction can be a royal pain in the neck.

Thanks for listening!

[cbarrow7625]

Actually, it looks like those two wiring diagrams are almost exactly the same with the only difference being the placement of the Master Tone control. In the Epiphone diagram the tone is placed in parallel with the MV input, in the Gretsch diagram the tone is in parallel with the MV output.

the question at hand is "...which is likely to offer the best, most versatile performance in terms of overall function and tonal variation?". It depends.....kind of. If the tone control & MV are both fully on 10, they will perform identically. Once the MV and/or tone are turned down there will be subtle differences. Because the Gretsch puts the tone on the MV output, the effect of the tone control is also manipulated, in part, by the position of the MV knob. On the Epiphone, the effect of the tone and MV will be completely independent of one another. So which gives the most "tonal variation"? The Gretsch, but by a fairly narrow margin.

I prefer to have the tone control after the volume and re-wire most of my guitars that way for the added tonal ranges/combinations. The effect is much more pronounced in a guitar with an HF bypass cap aroundthe master volume control; the volume pot resistance and treble bleed cap interact in interesting, useful ways.

For you guitar, you can't go wrong either way. Doubtful that most people using it would care or even notice the difference while playing it.

[Watermark]

Thank you very much for taking the time to respond and for providing me with such a detailed response - its been very helpful. Since posting this question late yesterday, I've received another (similar) reply from another knowledgable source, via e-mail, and he basically agreed with what you've said here (i.e., that there are too few if any meaningful differences between these two wiring schemes to worry about). So together, these two responses are reassuring. As a result, I can now proceed with diagnosing the problem at-hand (an intended ground or short somewhere in the harness), without having to concern myself with whether the harness itself may have been designed or assembled incorrectly. That saves me a lot of time and grief, so again, my sincere thanks.

[rjb]

Crazy Hunch from Left Field

I can now proceed with diagnosing the problem at-hand (an intended ground or short somewhere in the harness),

Carefully check the ends of all coax cables.
You may find a nick in the center conductor's insulation, where the shield is touching.
The short may be hidden and hard to see.
I once bought a brand-new mini-Strat for $20 because it had no output, and that was the main problem (of several).
And it hadn't been rewired- it came from the factory that way.

If the harness was rewired with low-microphonic cable like this
Canare Corp.: OFC Line, DMX, RS422 Cables: Guitar / Keyboard / Instrument Cable(GS-4)
be aware that the black plastic sleeve is conductive and must not touch the center wire.

[Watermark]

Thank you for the added feedback, and what you've said makes sense, but I think I'm O.K. on that score - its wired throughout with a sort of PVC-over-cloth wire which has the very fine gauge center hot lead at its core, covered by cloth insulation, then an outer wrapping or webbing of shielding (?) or ground wire. But to better explain just what's happening, let me provide a somewhat more detailed description of the circumstances (and please forgive my terminology on wire types if it isn't quite accurate):

First, and without suspecting any issue whatsoever with the custom made harness, I physically installed and soldered the entire harness into place, including to both pickups, four pots, and single 3-way, and then, in preparation for soldering the main output lead to the Output Jack, I stripped off about 1.5 inches of the outer PVC which exposed the braided webbing or shielding/ground (?) immediately underneath, followed by cloth insulated hot lead at the core. I then slid the entire sheath of shielding back about 3/4" as advised (away from the hot lead), and stripped about 1/4" of cloth insulation away from the hot lead to expose its tip for soldering. It was at this point that I discovered the problem . . .

Before soldering anything, I checked (using a multimeter) to see if the hot lead itself was isolated from the outer shielding or ground webbing, and it was a "no-go". Even before soldering to the Output Jack, I had (and continue to have) continuity between the central hot lead and the braided shielding or ground (i.e., no resistance = zero Ohms). And so, I interpreted this to mean that I've got a short (unintended grounding of some sort) of one or more components up inside the arch-top body somewhere, maybe at the Master Volume, Master Tone or 3-Way Switch? Whatever the cause, when the Output Jack is soldered into place and the instrument is connected to a small amp, there is no output from either pickup, regardless of the Switch position or volume/tone settings. No hum, no buzz, no nothing - even tapping the pole pieces of the P90, nothing!

Anyway, I suspect that I'm gonna have to thoroughly disassemble this little princess and start over from scratch, checking each and every component independently, which is never any fun, but I hope this added description helps.

Thanks again.

[Steve A.]

Actually, it looks like those two wiring diagrams are almost exactly the same with the only difference being the placement of the Master Tone control. In the Epiphone diagram the tone is placed in parallel with the MV input, in the Gretsch diagram the tone is in parallel with the MV output.

The difference you mention is called 50's wiring vs Modern wiring on many forums and in many people's opinion makes a big difference as you turn down the volume control. With the Gretsch/50's wiring you lose less highs as you turn down the volume which can eliminate the need for a bright cap or resistor/cap on the volume control (which can artificially alter the tone as with the .001uf cap on the volume pot with traditional Tele wiring- as you turn the volume control down the sound gets a lot brighter.)

I don't know why most mfgs switched to Modern wiring for their tone controls but I usually switch it back to 50's wiring on my guitars. (I plan to wire up a push-pull pot on one of my guitars to demonstrate the difference to non-believers. )

Steve Ahola

[Watermark]

Thanks Steve.

This is all great stuff, and very worthwhile noting, but I'm afraid much of it is above my current pay-grade and circumstances. I'm just an amateur, home hobbyist with an inexpensive but reasonably well-built Epiphone Wildkat, who is trying to fit it with P90s (my very first experience with P90s). And from what I hear, the stock Epiphone (or Gretsch) wiring schemes may not even be well-suited to P90s to begin with, since apparently P90 bridge pups tend to be rather spikey, thereby requiring different cap and/or pot values.

By example, both the Gretsch and stock Epiphone Wildkat wiring diagrams (above), the latter of which was intended for use with stock humbuckers, show a single cap at the Master Tone pot, and my current harness is rigged accordingly, with 500k pots throughout with a single .022 cap at that Master Tone pot. However, I'm seeing widely varying references out there for other P90-equipped guitars to .022 to .047 caps on all four pots, and 250k-300k pots throughout, etc. So to be quite honest, its all very confusing to me at this point. And the worst part is, I won't even know one way or another, until I can get the silly thing functioning, but when I do, I have a sinking fear that I'll be tearing back into it all over again, just to optimize the pups.

[Tony Bones]

worthwhile noting, but I'm afraid much of it is above my current pay-grade and circumstances. I'm just an amateur, home hobbyist

The path to enlightenment is paved with experimentation.

Just wire it up with the parts that you have, either by the Epi or Gretsch diagram. Play it for awhile, a few days at least. Then get out your soldering iron and change it...

[Watermark]

Well thank you for that sage advice - I'm already feeling "enlightened".