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Grease Bucket Circuit Woes
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Grease Bucket Circuit Woes
I’ve done the Fender Grease Bucket Circuit mod on a lot of Strats and it always works. A customer recently brought in a 335 kit for wiring. It got 3-TV Jones humbuckers, each wired to a Seymour Duncan Triple Shot Mounting Ring, 3 separate volume controls and a master tone with the Grease Bucket circuit. My client wanted to see a clear diagram of the wiring, so I got GuitarElectronics.com to generate one. I’ve used them several times in the past, they’re a great resource. All pots are CTS 500k, the switch is a short Switchcraft toggle and the jack is a PureTone. I normally use 2 part braided wire on hollow bodies because of the lack of shielding issues, but my client wanted cloth push back wire. I built the harness per the diagram EXACTLY, but I’ve got no tone control. I’ve kicked it back to Guitarelectronics.com and they said the diagram is accurate and works as shown. I’m by no means an electronics guru, but I’ve wired hundreds of guitars, some with very complicated wiring schemes. The only differences in this harness than normal are the CTS mini pots I had to use because the F-holes on this guitar are smaller than normal. Full-size pots were way too big to use. And, my client supplied Tropical Fish caps for the two caps in the Grease Bucket circuit. I tested those caps prior to building the harness and they worked. They’re very fragile though and I fear I may have damaged them while soldering. I’ve never seen them in a guitar before, only in wah pedals and amps. I went back over the harness with a multi-meter, point to point, several times and everything checks out except the tone control is a no go. I checked the funtionality of that particular pot, thinking I may have toasted it, and it’s good. The Triple Hot rings have little switches that allow you to make the humbuckers series or parallel or split coil. The Grease Bucket doesn’t work on any of those switching options on any pickup.
I plan to remove the Tropical Fish caps and replace them with some Orange Drops just in case I toasted them . If that doesn’t work, I’ll remove the Grease Bucket mod and wire the tone control like a typical tone control. If that works, the Grease Bucket for some unknown reason just doesn’t work with this particular harness. If it doesn’t work, I’m out of ideas. Any thoughts or advice are much appreciated. Thanks!
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6 Replies
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Hey Thom
I think the circuit looks good so, as long as you’ve replicated it, it seems like all should be ok. From what you’ve said, I understand that everything works properly except that, when you turn down the tone control (greasebucket) nothing happens — it has no effect. That being the case, it seems like there are a couple of possibilities that I can think of.
1. Something’s come loose as it was all being poked back into the f-hole. It’s such a fiddly job that it’s really easy to knock a wire or component loose as you wrestle with it. I’ve done it dozens of times. Double check the capacitor and resistor connections to the pot (and the cap-to-resistor joint too).
2. Triple check the ground wire going to the tone pot casing. If there no ground, there’s nowhere for the greasebucket to shunt signal to and nothing will happen.
3. As you mention, one of the components could be faulty. If you can replace the capacitors with alternatives, try that. Try another resistor. Try another pot. You may have some luck using a test lead or piece of wire to ‘bypass’ components as a test to see what happens but replacing them will be more certain.
As a last-ditch you could try installing a standard tone control arrangement and see what happens. If nothing else, it’ll point to the problem being in the tone area or in the rest of the circuit.
If I’ve misunderstood the symptoms, let me know. Also, let me know if this doesn’t work.
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One other thing (although you’ve probably already taken care of it): Those caps and resistor can present a lot of exposed hook-up wires. Make sure everything around there is well insulated so that nothing can short to somewhere it shouldn’t be. 🙂
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Thanks Gerry! The harness is still outside the body, and the 3 pickups with the Triple Shot rings are connected as is the bridge ground. I never install a new harness in a hollowbody until I know it works. I’ve been burned too many times. 🙂
Everything appears to check out. All the grounds are good. The switch and separate volumes work and the Triple Shots are working as advertised. Nothing is touching anything it shouldn’t, but I’m still without a tone control so something is still amiss.
I’m in the process of changing the tone control to just a standard tone, sans the Grease Bucket mod. I checked the tone pot itself and it’s working as specified as are the supplied caps and resistor. At this point, if a regular tone control works, I’m going to try to convince my client it’ll be fine without the Grease Bucket mod. I’d really love to know why this isn’t working, but I need this out of my life.
I’ll update later on how this shakes out.
Thanks again! Love your book, BTW! 👏
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I’m wondering if it may be just a frequency thing. The greasebucket is meant to be paired with a 250K pot and the caps & resistors paired with that particular pot. Perhaps what it’s doing is simply not audible to the ears. I gather why you used the 500K but it just might not be the right pairing for the desired outcome.
For instance, here’s a pile of treble-bleed circuits I’ve built for various pickup and pot configurations – some of these won’t do an audible thing when clipped into a certain pickup/pot combination and some are very obvious.
Doc
* within this pile are 2 different bleed circuits for TV Jones pickups dependant on whether I’m using a 250K or 500K pot. The 250K one is fairly similar to a Fender bleed for 250K pot but, the 500K has a much higher capacitor value. I’m not an electronics guy but giving this logic, I would consider perhaps a .04µF capacitor in-series with the 4.7KΩ resistor
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Thanks, Doc!
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Update: I never could get the Grease Bucket circuit to work. Everything checked out, it just didn’t work. I tried several different values of caps on the circuit as a typical tone pot configuration. I ended up using a .033 cap that worked OK. I’d still love to know why the Grease Bucket circuit didn’t work but I’m in agreement with Doc that it must have a frequency thing. The next customer with a triple humbucker equipped guitar thats wants the Grease Bucket mod is going to hear a resounding “No!” from me.
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