Wiring help! Cant wrap my head around this scheme!

[ew57]

Greetings all! I’ve come to grips with my ineptitude and am willing to admit that I cant seem to think up a scheme to wire a P rail to access the rail, p90, humbucker parallel, humbucker series & off while only using three poles of a Superswitch AND not have a hanging or shunted coil. I’d think this is possible, but I just don’t have the chops to pull it off! Any hints/ideas?

[sumgai]

ewwie,

Since you've specified using three poles of a superswitch, then yes, it can be done. Take a normal schematic for any two coils that connects them as one, the other, both in series, then both in parallel, such as this one:



Simply use the third pole to connect the Neck's hot lead to the rest of the wiring diagram in those switch positions where the Neck is used. Presto! instant no shunt or hanging hot.

Above, you'd want the switch to make the connection in positions 1, 2 and 3, and break the connection in position 4. The shunt wire is no longer of use, so there's no point in putting that into the circuit. (It's the one going from the upper pole of the switch to the Neck's hot lead, in position 4.)

What I drew above is for a sort-of standard Tele 4-way pickup selector switch. In your case, you can connect up the first four positions of a superswitch as I've shown, and the fifth switch position becomes "Off".

BTW, in the most ideal scenario, you'd ensure that there is no chance of any sound, nor of any noise, coming from your guitar when in the Off position. To do that, you'd simply short-circuit the output jack's "hot' terminal to the so-called ground terminal. (These days, we're in the Official ChrisK frame of mind - it's properly called the "signal return" conductor.) That can still be done with the same "third" pole of the superswitch.

And just out of curiosity, why did you specify only three poles of the superswitch? Do you have something planned for the fourth pole?


HTH



sumgai



p.s. How many months now have I had this no-longer-new laptop, and I still haven't installed AutoCAD..... sigh.

[ChrisK]

These days, we're in the Official ChrisK frame of mind

And indeed it is a frame of mind. Virtually no terminal on any component is a/the ground terminal until we connect it there. Calling things "ground terminals" encourages bad thinking behavior. We quickly lose sight (if we ever had such insight) of the possible flexibilities en-circuit, as we view things preordained.


This is the fundamental key to new switching and control design.

"Seeing beyond the shackles and practices of today's wiring layouts (instantiations of schematic designs) and schematically considering all things as being modular, and tied to the "ground" only when appropriate."

One MUST see schematically in order to "see".


The key to this enlightenment in this case is that the "ground" conductor from each coil is just a signal conductor, no different (except differentially or signal phase-wise) from the other conductor from each coil.

Since phase is only relatively to something else, even if we wanted phasing, only three poles are required, as one wire can always be connected to the guitar signal return (ground).

Since we want something paralleled as well as elevated (series - standing on its brother's shoulders) AND we want nothing hanging OR shunted (if only either one is stipulated, only two poles are required), then three poles are required.


What sumgai is saying, is that you need to switch three things (I kept the Bridge and Neck references to ensure continuity with his referenced design as well as for my coming inference to two pickup guitars);

the Bridge (P-90) output,

the Neck Return (Rail) and,

the Neck (Rail) output.

The Bridge (P-90) return is grounded.

Modes
1. Rail
2. P-90
3. Both parallel
4. Both series
5. Off

P-90 return grounded

P-90 output pole
1.
2. Output
3. Output
4. Rail return (AA)
5.

Rail return pole
1. Ground
2. Ground
3. Ground
4. P-90 output (AA)
5. Ground

Rail output pole
1. Output
2.
3. Output
4. Output
5.


Note that since one is switching both leads to the Rail pickup, one could reverse its phase as well. While this won't be of the best sound intra-pickup like this, this model easily extrapolates to two pickups (a' la Tele) where one has 5 combos instead of four, now including series out of phase (SooP). Or, one can do parallel out of phase (PooP) or parallel half out of phase (PhooP) (also known as the Jerry Donahue Tele).


Many times I'll do switching layout designs with function tables in a spreadsheet rather than schematically at first. This way I can "see" many patterns, and hence opportunities.

[ew57]

Excellent stuff guys, I really appreciate it! The intentions for this were briefly discussed in this thread: guitarnuts2.proboards.com/index.cgi?board=wiring&action=display&thread=3739

But to summarize, I wanted a superswitch for each P-rail, then join the two pickups together yet minimize interaction between the two circuits. Some switching methodologies towards the end of that thread were interesting & thought provoking, but they were well beyond my skill level.

I have been looking at different onboard preamps, and also ways of minimizing the interaction found on dual volume/tone setups. Ranging from as simple as implementing summing resistors to something similar to one of Albert Kruezers designs: www.albertkreuzer.com/preamp_onboard.htm



I have little interest in the EQ section he has implemented, so that would simplify things.

Comparing the above design to the Tillman buffer showed a fair amount of similarities, and thinking back to JohnH’s buffer/source follower, I thought that may work for the 1st stage(s) then feeding into something like the Fetzer Valve circuit to recoup the lost gain from summing function and/or increasing gain even further.

My interest in using only three of the four poles of each superswitch goes back to a recommendation by JohnH to be able to disconnect each pickup/volume/tone circuit from the circuit when in the “off” position.

Any suggestions/comments/concerns? Thanks again for your help guys, I really appreciate you sharing your time & expertise!

[ChrisK]

ways of minimizing the interaction found on dual volume/tone setups.

Well, make up your mind! You either want dual adjustable control sets or you don't.

My interest in using only three of the four poles of each superswitch goes back to a recommendation by JohnH to be able to disconnect each pickup/volume/tone circuit from the circuit when in the “off” position.

At a minimum, if you look at my posted P-Rail design (I have unposted fuller-featured designs as well), you'll see that I reverse wired the volume pots. The pickup structure goes to the wiper and the top ("10") volume pot terminal goes to the output switch (or in your case, jack). This ensures that one volume turned down does not affect the other.


Modes
1. Rail
2. P-90
3. Both parallel
4. Both series
5. Off

P-90 return grounded

Tone circuit goes from pickup volume pot wiper to pickup ground.

P-90 output pole
1.
2. Pickup volume pot wiper
3. Pickup volume pot wiper
4. Rail return (AA)
5.

Rail return pole
1. Ground
2. Ground
3. Ground
4. P-90 output (AA)
5. Ground

Rail output pole
1. Pickup volume pot wiper
2.
3. Pickup volume pot wiper
4. Pickup volume pot wiper
5.

Pickup volume pot output (CW terminal) pole
1. Output jack
2. Output jack
3. Output jack
4. Output jack
5.


There will be interaction only when both pickups are on. The reversed connections to the volume pots will help aleviate interaction from one turned down affecting the other.

Both tone controls will still work when both are on. If there is too much cut from both turned down, be "Fenderly" aboot it and "share a cap".


While active buffering can eliminate any interaction between the two pickups, I'm not the biggest fan of this since it eliminates any interaction between the two pickups (I like the shared passive component effects).

[sumgai]

Gotta go with Chris's last statement, the part about sharing passive components. Two inductors in series or in parallel have a much different sound than two active circuits that are summed into a mixer via resistors. Not to mention, two pups in series won't be possible, if each is fed into its own amp circuit. Well, not until you start saving your shekels so's you can invest in a intrumentation amplifier for each pole.

If you really need to isolate the two pickups to "avoid interaction", why not go in the opposite direction, and blend them? Hooking them to opposite ends of a single pot works, but it's better to use one of Chris's Blender circuits, as explained here. Or, in very condensed form (no explanations, you'll have to ask for help), here.

As much to the point, I too am a switch freak, of sorts. But having so many switches that duplicate the Off function can be hazardous to your stage image! Consider staying with 4-way switches for each of the pups, and the master is the only one that can kill the whole shootin' match. Too, I think if you check out Chris's PRS Rotobucker, you'll find a whole new way to get what you're asking for, and with a simpler way to operate the furshlugginer thing. ;D

HTH



sumgai