Simple Les Paul mod - no new parts

[JohnH]

This is a good simple way to get extra single-coil sounds from a Les Paul or SG, without changing or adding any pots or switches. Single-coil sounds are provided at the end of the tone control range, as the knob approaches 10, adding an extra bright extension to the normal range as the pot starts to bypass one of the humbuckers coils. At 9 and below on the tone controls, the full humbuckers sound is maintained, with tone control to taste. The system for wiring a tone pot in this way is attributed to Red Rhodes. Further discussion and outline schematics may be found on these threads:

guitarnuts2.proboards45.com/index.cgi?board=wiring&action=display&thread=1178267584
guitarnuts2.proboards45.com/index.cgi?board=schem&action=display&thread=1145315219



I currently have this wiring in my Gibson LP Studio, and it has allowed me to check out the 4-conductor mod that I did to the pups, while I think about a more complex scheme. The thing is, it works very well and with those extra coil-cut sounds, it gives me most of the extras that I use. Although I miss series and out-of-phase, I cant put it down for long enough to rewire it any more!

The bypassing to create the single coil sounds can be via a wire for a complete bypass, or through a cap which leaves some humbucker bass sound. These part schematics show the tone wiring with or without the extra cap. The remainder of the circuit is standard:



I found the partial bypass was best on the bridge pup, while full bypass was preferable on the neck.

For the wiring diagram, I have shown it with Seymour Duncan colours, in which the single coil sounds will be the slug coil at the neck and the adjustable coil at the bridge, for hum cancelling. In my built version, I also did some further wire and magnet flippage to get both adjustable coils as hum-cancelling. The diagram is also based on the use of a metal ground plate to the control cavity, with tags for ground and hot, which some Gibsons have, including mine. Its easy enough to do without this however.

It's a good starting mod, and it expands the basic sounds on an LP from 3 up to 8. I am using it with a Gibson 490 at the bridge and ’57 Classic at the neck. I particularly like the mix of neck Hb with Bridge Sc on these pups, which is full and warm with a nice dose of single-coil edge.

cheers

John

[maxcalibur]

Do any or all of the pots shown in this diagram need to be logarithmic?

[JohnH]

Sept 9, 2010 3:41:37 GMT -5 maxcalibur said:

Do any or all of the pots shown in this diagram need to be logarithmic?

The circuit works fine with log or linear pots, its just a matter of persnal choice. In each case, you get the same overall range of sounds. I have similar circuits on two of my guitars, one with linear, one with log.

fr the volume pots, its the same factors that usually apply in this choice, do you prefer a gradual reduction of volume as you turn down from 10 - better for controlling clean volume and setting mixes of the two pups - in which case linear pots are best. Or do you want to get a sharp drop in volume quickly, better for taking a high gain sound and 'cleaning it up' - in which case log pots may be better. Actually, for volumes, I like log pots with treble bleed circuits (220k and 1nF cap in parallel across hot and centre vol pot lugs). This gives a volume fall off in between log and lin, and also preserves treble at lower volume.

On the tone pot here, if you have a linear 500k tone pot, you will be able to control the transition from humbucker to single coil, as you turn from 10 down to about 8 or 9. With a log tone pot, it happens very fast. At 10 you have single coil, and before you get to 9 it is humbucker. Personally, I quite like the positiveness of that.

On the circuit, my current preference is for C2 to be 47nF = 0.047uF, thats the cap that sets how much bypass there is on the bridge pickup. I think this is a matter for choice as well, and is dependent on the pickups.

For myself, this design got built into my LP studio, and then morphed into this design:
LP modular wiring

If you take a look at that thread, the main cavity wiring is similar but not identical to this - but has the features I describe above and can also be extended to add further switching features such as series and phase.

But the basic version on this thread actually has all the sounds that I normally use. If I pick up anyone elses LP with just normal settings, I cant stand it now - I really want these sounds!

John