uOpt
Something Cool
I mentioned this in a few threads. This is what I now use when I test pickups.
I got fed up wondering about these "what this would sound like with 250 Kohm pots and/or a 22 nF capacitor?" questions and speculate about these "no way you can hear ..." issues.
One volume pot simulator with 1 Mohm, 500, 250 and 100 Kohm and "none". One tone control with a 1 Mohm poti (which can perfectly emulate 500, 250 Kohm and lower), tone cap switchable between 10, 22 and 47 nF and "off" and a turn switch for a "load" capacitor.
The current "production" version also has a LCR network integrated with an on/off switch. I use Bill Lawrence's "Q-Filter" here:
The normal attachment to the pickups is via the crocodiles, with an extra croc for grounding the guitar. Works pretty well for braided wire. For the 4-conductor awg 28 wires I usually prepare the pickup that I want to test by soldering awg 22 extensions to each of the awg 22s. The nice thing is that you can instantly attach the crocos to the right wires to get exotic combinations like "out of phase in series but only the north-up coil of the neck pickup". So no more wondering there either. There's a normal plug between the harness and the crocs, so you can just use a standard plug if you don't trust the crocos.
It's work in progress, actually the above pictures are already out of date. For starters, some idiot sent me 5-position switches when I wanted 11-positions and my load capacitors are too heavy, at least for humbuckers. That's getting redone at a finer scale after people send me back my Strat parts.
And I discovered that what you really want is two of these harnesses with one master switch to engage one or the other. The problem is at least with mellow pickups it's very hard to hear the minor differences such as a 250 versus a 500 Kohm poti or the difference between a 22 nF and 47 nF cap with a 500 Kohm poti at full open. But you can easily hear the difference when you change all potis from 500 to 250 Kohm and the cap from 22 to 47 nF. So what you need is two of these, you set one to the static "reference" that you want to compare against and then you have a switch switching back and forth between the reference and your live experiments.
These "reference setups" could be without potis, just hardcoded to act like 500/500/.022 and 250/250/.047 with pots full open, to save space.
The whole thing has a little bit of it's own capacitance, 0.6 nF. That's more than I wanted but probably OK. It's like using a longer cable and you can make good for it by using it with a shorter cable between the harness and the amp.
I also want some of these fat expensive "vintage" capacitors of the same values in the tone control to compare them to the ceramics. So the tone control will get a switch that switches, for whatever cap value you have currently selected, from "el cheapo ceramic" to "ripoff vintage".
A proper case is coming in the next version, but I probably re-design the whole thing to reduce capacitance first. The noise right now isn't too bad, and you can just lay the whole thing in a bed of grounded aluminium foil.
I feel much better about my testing now. The looming "is it worth digging out the other pots?" was driving me nuts.
I got fed up wondering about these "what this would sound like with 250 Kohm pots and/or a 22 nF capacitor?" questions and speculate about these "no way you can hear ..." issues.
One volume pot simulator with 1 Mohm, 500, 250 and 100 Kohm and "none". One tone control with a 1 Mohm poti (which can perfectly emulate 500, 250 Kohm and lower), tone cap switchable between 10, 22 and 47 nF and "off" and a turn switch for a "load" capacitor.
The current "production" version also has a LCR network integrated with an on/off switch. I use Bill Lawrence's "Q-Filter" here:
The normal attachment to the pickups is via the crocodiles, with an extra croc for grounding the guitar. Works pretty well for braided wire. For the 4-conductor awg 28 wires I usually prepare the pickup that I want to test by soldering awg 22 extensions to each of the awg 22s. The nice thing is that you can instantly attach the crocos to the right wires to get exotic combinations like "out of phase in series but only the north-up coil of the neck pickup". So no more wondering there either. There's a normal plug between the harness and the crocs, so you can just use a standard plug if you don't trust the crocos.
It's work in progress, actually the above pictures are already out of date. For starters, some idiot sent me 5-position switches when I wanted 11-positions and my load capacitors are too heavy, at least for humbuckers. That's getting redone at a finer scale after people send me back my Strat parts.
And I discovered that what you really want is two of these harnesses with one master switch to engage one or the other. The problem is at least with mellow pickups it's very hard to hear the minor differences such as a 250 versus a 500 Kohm poti or the difference between a 22 nF and 47 nF cap with a 500 Kohm poti at full open. But you can easily hear the difference when you change all potis from 500 to 250 Kohm and the cap from 22 to 47 nF. So what you need is two of these, you set one to the static "reference" that you want to compare against and then you have a switch switching back and forth between the reference and your live experiments.
These "reference setups" could be without potis, just hardcoded to act like 500/500/.022 and 250/250/.047 with pots full open, to save space.
The whole thing has a little bit of it's own capacitance, 0.6 nF. That's more than I wanted but probably OK. It's like using a longer cable and you can make good for it by using it with a shorter cable between the harness and the amp.
I also want some of these fat expensive "vintage" capacitors of the same values in the tone control to compare them to the ceramics. So the tone control will get a switch that switches, for whatever cap value you have currently selected, from "el cheapo ceramic" to "ripoff vintage".
A proper case is coming in the next version, but I probably re-design the whole thing to reduce capacitance first. The noise right now isn't too bad, and you can just lay the whole thing in a bed of grounded aluminium foil.
I feel much better about my testing now. The looming "is it worth digging out the other pots?" was driving me nuts.
)
. But the pickups there are a CC/PG hybrid and a 1980 T-Top and maybe they don't mix. Or the guitar doesn't come up with the right frequency spectrum. In any way, good to know that you can save the OOP trouble in this guitar.
