Gimme some ... ... ... tone

Ok here is the first go at the circuit . . . I'm not sure I'm 'sold' on the greasebucket I have on the tone pot but I want to try it ...

And it's back together . . . .

Well . . . it's back together.

Body cavity lined with copper (in progress) . . . check

Wiring complete . . . check

Tune up, let it rest a bit and redo the action & intonation . . . working on it . . . 

Ok it was a little more complicated than that . . . 

. . . there was a faulty switch in the neck PU coil selection unit that took me a while to run down, though I learned a new trick soldering switches . . . or maybe relearned an old one. 

. . . the original placement of the treble bleed prevented the guard from falling into the right place . . . and then when bent to a more 'convenient position' shorted out against the copper lining.

. . . when testing the resistance readings got really weird . . . due to a inversely wired tone pot . . . and then the volume pot behaved weird (see below).

. . . and then there is the switch in the tone circuit that behaves . . . not like it should . . . despite testing OK . . . 3 times . . . there seems to be some kind of 'non continuity' there that prevents the tone pot from correctly shunting signal to ground via the cap . . . which may be a wiring fault . . . 

The coil selection (where I though I had a wiring fault) now works flawlessly; GOOD. The treble bypass is quite subtle but noticeable. However, my trim pot went missing so I'll have to redo that part once a replacement comes in; OK. And then there is the tone knob . . . I think I have another faulty switch there - despite the fact that it seemed to check correctly - as there is something weird going on, I get (almost?) no tone rolloff when I have it in the prevolume position, while it - occasionally - DOES work when in the postvolume position . . . SO . . . that's another thing to check out . . . . . 

OH and this IS the LAST time I do anything this COMPLICATED . . . . . . . . . . . . the rewire took two solid days of work to complete . . . . . . 

. . . and there is something WEIRD on the volume pot; if you measure resistance between the IN & OUT lugs of the volume pot when wired up the resistance goes from 0 to 480K (or so) when turning the wiper and then on the last 5% of the range or so DROPS almost instantly to almost 0 on one of my multimeters . . . . the pot itself is fine . . . I unwired and rewired it twice thinking I had damaged it in soldering the leads . . . it behaves as it should but there is something WEIRD going on in the circuit . . . I'll have to see if I can run down next time I get the guard off.

Stupid mistakes . . . and a redo of the wiring diagram ... again

AND . . . one more time

OK so I managed to do a number on myself with the last revision of the coil selection switches . . . it was WRONG (mea maxima culpa) so that's been corrected - thanks to another question about humbuckers and series switching, I should trust myself a little more . . . SD humbuckers connect red to white for series . . . and that just wasn't happening before. The tone stack has also been revised. The 'grease bucket' (tm)  circuit has been removed as I couldn't figure out how to build it and a regular tone circuit on the switch ... I'll try that one again when I have some more time . . . AND . . . I wanted to try a treble bleed from the beginning so that's in there now with an on/off switch so I can see what and how much it does.

Making progress . . . . .

. . . . so far all the checks seem to come back as they should.

Left to do, build the treble bypass, finish the tone switch & knob . . . . . and wire it all to the jack. And ... transfer the harness to the actual pickguard and wire in the pickups . . . .

Oh and it turns out that guitar making IS a transferrable skill.

And ... another rewire . . . .

OK, after a while the neck pickup in the JM developed an annoying ... seemingly unreproducible problem . . . scratchiness . . . anyway it was painfull to listen to SO back to the diagram and trying to find WHERE I went wrong . . .

Well no faults leading to scratchiness were found . . . BUT . . . it look like the humbucker coils were wired out of phase . . . OUCH . . . start and end somehow got interchanged on the P90 part of the pRails.

EDIT / UPDATE: NO, no, NO . . . they were NOT . . . it's now been corrected in the next post

OK so here is the new diagram . . . and apologies to anyone who tried it . . .

So I took the whole instrument apart and . . . well in the end I think that an non insulated ground wire in the pickup coil switching circuit occasionally could make contact with the hot signal from the neck pickup depending on the vibration and other factors . . . not solid contact mind you, but just kinda glancing off of it ... thus the scratchyness . . . ??? . . . that's the only thing I could find remotely problematic electrically . . . and of course . . . it's hard to see through a solid wood body or pickguard and things undoubtedly move on installation and . . . . 

Also took the opportunity to rout out some 'tight spots' where the pickup legs were a 'tight' fit and to rout a shorter path from the bridge pickup to the coil switching circuit in the upper horn . . . and debating whether I want to coat the whole interior with copper shielding foil while I have it apart . . . 

Anyway here are some shots of work in progress:

First shot is the coil switching circuit being built. The second has the coil switching circuit and the phase switch complete and the rotary pickup selector switch is being built. No cloth wire this time, it's not bad to work with but I didn't have enough for a complete rebuild and it's more bulky than the silicone insulated hookup wire.

Volume & tone next week, I have to have a look at the tone circuit before I put that in (EDIT: done that and yes there was a mistake that has been corrected), the SPDT on/off/on switch should switch the tone circuit before or after the volume pot . . . just to try if it make a difference (quite possibly not), the other switch should give me a straight cap like a normal tone circuit OR a version of the Fender grease bucket circuit . . . 

One more circuit . . . .

Switching 3 PU off/series/parallel the switch positions would be better labeled off/out/send as the last setting sends the signal to the next PU in the chain and the middle position sends it out of the chain.

And here is the 2 PU version . . . .

Guitar circuit revision

The original circuit I showed some posts back works but I'm not satisfied with how the tone knob works (or rather what it does ... or maybe that should be doesn't) do to the tone so it's time for some more experimentation. I may actually temporarily change the tone switch to switch between an onboard traditional tone circuit and and 3.5mm connector  hanging out of the pick guard so I can easily test different tone circuits but we'll see. Oh and the treble bleed never got implemented . . . still have to try that BUT it's another switch and I never drilled the hole for that one . . .

So here it is . . . . the complete circuit . . . .

SD Prails pickups, my version of triple shots, phase switch and rotary 4 position PU selector with selectable treble bleed as well as selectable tone circuits traditional tone and greasebucket circuits . . . . NOT sure about the value of the tone pot yet . . . may keep that as a 500K but then I may solder a 500K resistor from the 0.1 to 0.022 caps to change it to a 250 when switching in the greasebucket. I currently have a linear tone pot BUT the first 1/3 seems to do pretty much zip thus the substitution of a log . . . the volume is already a log but I saw that the original circuit actually had a linear . . . I'm happy with the log so I may well keep it.

Series JM mod . . . .

JM mod ... NO rythm circuit, rytm switch switches between the PU switch and PUs in series.

Neck volume/tone would be Master with PUs in series.








Alternatively . . . .

Another circuit

Phase + Series/Paralel + 3 Way PU selector

Oh and I'm working on something new, think 4 way blade switch, Lace Alumintone PUs, fixed bridge and GraphTech Ratio Tuners . . . getting close to being able to show . . . something.

2 and 3 way switches for single coil switching

A question led to drawing out the schematic for switching 2 single coils with a 2 & 3 way slide switch . . . here it is.

More Switches

Ok, so the last circuit had the 'hanging coil B' problem and a 3P4T switch that turns out to be kinda hard to find . . . Digikey  has one with a true common terminal configuration BUT it's a through hole PCB mount and not a panel mount solder lug style . . . possible but . . .

So here is the revised circuit using a 3P4T rotary which is common and easy to obtain . . . AND . . . it solves the 'hanging coil B when coil A is selected' problem, which in turn implies that the same is possible with some work for the 3P3T / 3P4T slide switches configuration.

May use this in the guitar . . . . 

A gift . . . . because I was bored

Well I wondered if it was possible to use one switch for coil selection and a second for the combination . . . . turns out is is possible with 2 3 pole switches, one 3 pole 3 throw for coil selection (A, both, B) and one 3 pole 4 throw for selecting the combination (serial, parallel, serial out of phase, parallel out of phase).

I haven't tested this but the connections 'work' I believe:

The only 'mistake' I have to solve is the fact that coil B hangs loose (is not grounded) when coil A is selected. The only 'fix I've found is to use a 4 pole 3 throw switch there instead and use that 4th pole solely to connect B to ground in the UP position.