Help checking my wiring diagram

[dougle]

Hi All,

I'm a first-time modder (and forum user) looking for help checking that a wiring diagram, which I've created by amalgamating a few mods I found online, to see if it will function as expected.




Setup
Epi Les Paul + 2*SD P-Rail pups + 2*SD Triple shots

I've taken the following three mods and have attempted to combine them...
1) Jimmy Page mod using Triple shots and two push-pulls
2) Bass / Treble mod
3) switchable caps mod

Expected functionality:
-- triple shots will allow switching between HB + SC + P90 + HB parrel/series for each pickup independently --- this is taken directly from the SD diagram so presumably works
-- The vol push pulls will switch phase and series/parallel when both pickups are on
-- one set of tone controls to work for both pickup (ie lose independent tones control for each pup)
-- the bass control will cut out the bass at different frequencies depending on the cap chosen by the push-pull
-- the treble tone control will work as "normal" apart from the cap value is switchable
-- uses the "50s style" setup putting the tone controls after the volume resulting in the documented interdependence between vol and tone


Concerns / ideas


1) Perhaps I've messed up the wiring and it won't work

2) in the Bass/treble mod diagram that I used as a basis for my changes the input into the treble tone pot was on the opposite lug to where I have put it -- It seemed to me the original way would have produced minimum treble when the dial was at 10 -- so I swapped it around in my diagram

3) negate interdependence between vol and tone with 50s wiring idea:--

         quite possibly very nieve idea but here goes....

        Idea: - connect the 2nd gang of the 2 gang push-pull of the treble tone pot to the input and output lugs of the vol pots. Logic is as follows....

        with normal 50s wiring ():
        --- treble pot changed from 10 to 5 = drop in resistance between ground and output on vol pot = lower voltage output due to impact on the voltage divider

        with treble pot 2nd gang bridging input and output of vols pots via its adjustable resistance
        --- treble turned from 10 to 5 = drop in resistance across output and input of vol pots thus reducing the imbalance caused by the reduction of resistance         across the ground and output = vol less affected by changes in treble pot value

Cheers
Douglas

[dougle]

wrt the idea to negate some of the interdependence of the vol and tone pots:-- there would need to be a resistor placed in series with the 2nd gang connection which approximated the resistance (impedance ?? ) of the cap in the vol pot (otherwise the vol would presumably max out as the tone was turned to 0)... any way the idea is to try to keep a similar taper on the vol pot irrespective of the tone position...

[newey]

I haven't fully gone through the tone control setup yet, so there may be issues there as well. What I do see is:

-- The vol push pulls will switch phase and series/parallel when both pickups are on

Sorry, nope. The phase switch is fine, but the series/parallel switch will switch the pickups normally when set to parallel, but in series mode you will get both pickups in series when the three-way switch is set to either bridge or middle positions, and when the switch is set to the neck position, you will get no output whatsoever, you'll have a dead spot.

There is probably a way to fix this, but have to go think about actual work for a while.

Also, I think you have swapped the labels on your volume controls- as shown, the bridge pickup is wired to the pot marked "neck Vol" and vice versa.

[Yogi B]

Mar 6, 2018 19:34:55 GMT -5 newey said:

in series mode you will get both pickups in series when the three-way switch is set to either bridge or middle positions, and when the switch is set to the neck position, you will get no output whatsoever, you'll have a dead spot.

I wish SD and others had this right in their Page-esque diagrams, but perhaps they're just being authentic to the original (botched) Gibson version.

I'll let reTrEaD do the talking on this one:

Dec 16, 2017 13:58:51 GMT -5 reTrEaD said:

Here's a drawing which displays the strategy of a Series Override with a standard 3-way pickup selector. It applies to a Tele, LP, or any two pickup design where the 'both' selection is Parallel. The selector is just represented by a box. Specifics will depend on the particular switch being used.

The dots represent the lugs of a DPDT switch. Those filled in blue are the poles. The blue lines represent the connections being made inside the switch, depending upon the position of the toggle.

In the Series Override mode, the position of the 3-way selector becomes irrelevant. The Bridge (+) is ultimately connected to hot regardless of the selection of Neck, Both, or Bridge. The Neck (+) is linked in series with the Bridge (-).

Or if you'd prefer a look of how that works in context, I can't think of a better place to look than JH's Jimmy Page.

Mar 6, 2018 17:01:47 GMT -5 dougle said:

negate interdependence between vol and tone with 50s wiring idea:--

quite possibly very naïve idea but here goes....

Idea: - connect the 2nd gang of the 2 gang push-pull of the treble tone pot to the input and output lugs of the vol pots. Logic is as follows....

with normal 50s wiring ():
--- treble pot changed from 10 to 5 = drop in resistance between ground and output on vol pot = lower voltage output due to impact on the voltage divider

with treble pot 2nd gang bridging input and output of vols pots via its adjustable resistance:
--- treble turned from 10 to 5 = drop in resistance across output and input of vol pots thus reducing the imbalance caused by the reduction of resistance across the ground and output = vol less affected by changes in treble pot value

I can't visualise what you're getting at here, if you tie the second gang of the treble control to both volume controls, then you've also permanently connected the volume pots together! However if you've got dual gang push-pulls there's a better way: simply wire each gang as you would a regular (non-50s) tone control. This gives you the master tone control without the drawbacks of 50s wiring. This would require modifying the cap switching, as well as doubling the total number of caps. The same thing applies to the bass control too, so you'd also want a dual gang there (if you don't already plan to).

Am I remembering correctly that it's preferable to use a linear taper for bass-cut controls? If so some pot surgery may be required to get a dual gang linear push-pull.

[reTrEaD]

Mar 6, 2018 21:51:29 GMT -5 Yogi B said:

I'll let reTrEaD do the talking on this one:

Wow. That was as recent as December? I had forgotten I even drew that.

[sumgai]

Mar 7, 2018 0:08:05 GMT -5 reTrEaD said:

Mar 6, 2018 21:51:29 GMT -5 Yogi B said:

I'll let reTrEaD do the talking on this one:

Wow. That was as recent as December? I had forgotten I even drew that.

Does this mean that we slave-drivers have to let up a little bit?

[dougle]

Great thanks for the help.

I'll see if I can redraw it with the changes suggested.

If I were to set it up 50s style and then change my mind later and convert it to the modern wiring is there any issue with detaching the soldered joints and changing the wiring?

If I did want to change it to modern style (using the double gang as suggested) would it be ok to leave the bass tone pot downstream of the vols without adverse effects?

Do I understand it correctly that installing a JFET buffer at the output jack, as per the JH JP design, solves the issue of treble being lost when reducing the volume?


I'll have to confirm the taper of the bass pot in the original mod description...all the ones I ordered are audio taper. I've ordered 4 double-gang push-pull pots with audio taper do this should give me quite a bit of flexibility.

Lastly the comments also reinforced two points (a) don't assume that the wiring diagrams from manufacturers are correct (it seems both the labelling and wiring were flawed in the diagram I based this on, and (b) draw out my ideas before communicating them --It was 2am and I was so focused (and slighly perplexed) on trying to apply partically learned concepts around pup and cable capacitance and impedance, impact of voltage dividers when adding caps/resistors in parallel over different lugs, and average resistance accross caps etc that the more obvious point that my idea wouldnt work anyway in the context of two vols went unnoticed (doh!)

Thanks again
Douglas

[Yogi B]

Mar 8, 2018 8:59:26 GMT -5 dougle said:

If I were to set it up 50s style and then change my mind later and convert it to the modern wiring is there any issue with detaching the soldered joints and changing the wiring?

Not really so long as you're at least half decent with a soldering iron.

Do I understand it correctly that installing a JFET buffer at the output jack, as per the JH JP design, solves the issue of treble being lost when reducing the volume?

Yes, plus with the additional resistors it also helps to eliminate the issue of turning down one volume completely cutting the signal in the both pickups in parallel position. An alternative could be to add treble bleeds to the volume pots. Plus with the dual gang pots you've even got JH's improved treble bleed as an option.

If I did want to change it to modern style (using the double gang as suggested) would it be ok to leave the bass tone pot downstream of the vols without adverse effects?

Well as it stands the bass control won't work too well, if at all really. Turing the bass knob even slightly down will lose you quite a bit of treble, the rest of the rotation only serving to cut enough bass to make the resulting output roughly 'flat' again, though obviously at a lower volume. There are two solutions to this, either introduce the buffer or have the bass control pre-volumes. 

Edit:

I'll have to confirm the taper of the bass pot in the original mod description

I've been thinking about this further: it's dependent on which way round the bass pot was designed to operate, as well as the specified pot value. If it's designed with the neutral tone at fully up then it's likely that the design specified a anti-log pot -- if the other way around, then a regular log pot. The extent of the non-linearity of the pot is determined by the value of it's total resistance: The larger the pot, the more non-linear. I'd say that the cross over point is at around 1 Megohm (1000 Kilohm) at values less than that I'd recommend a linear taper, for values greater than or equal I'd recommend the relevant log or anti-log taper. Of course this is also subject to personal taste.

(b) draw out my ideas before communicating them --It was 2am and I was so focused (and slightly perplexed) on trying to apply partially learned concepts around pup and cable capacitance and impedance, impact of voltage dividers when adding caps/resistors in parallel over different lugs, and average resistance across caps etc that the more obvious point that my idea wouldn't work anyway in the context of two vols went unnoticed (doh!)

I've done that even after drawing them out, don't worry!

[dougle]

I've had a go at changing the wiring (as follows) to address the issues mentioned:

- moved the tone pots upstream of the vol pots so they are more effective and used the 2nd gang to ensure that the vols are not permanently connected
- changed to series/parallel switch so that it works on any of the 3-way selector switch settings
- corrected the naming of the vol pots

I've followed the path and all seemed to check out but would appreciate a 2nd pair of eyes before I start installing it ... well, that is when the parts arrive - they somehow ended up in Lisbon (from the UK) even though I live in Spain...




Diagram Notes: --
Colours
Red - input neck vol
Yellow - output neck vol
Blue - input bridge vol
green - output bridge vol
Brown- ground
orange- output to jack
Black - other

caps are not connected together although it may seem like that in the diagram
gaps in wires represent where they cross other wires
Treble bleeds omitted from the diagram - for simplification -  but intend to try a small trim resistor in parallel to a cap between input and output lugs of each the vol as suggested

Thanks again,
Douglas

[Yogi B]

Looks good, the only change I'd make is to move the grounding of the neck half of the treble control to happen via the series/parallel switch. This has less caveats than usual since both halves of the control work simultaneously, but I'd still change it.

As it stands when the treble is rolled all the way off the cutoff frequency will be in about the same place as in the parallel mode -- however the series position will, overall, be a little darker, due to the neck half of the tone control loading both pickups, rather than just the neck. Or at least with both volumes fully up, as it's also dependent on how the pickups are blended (with the bridge all the way off it'll work like the version below).

Swapping it will make the series position a touch brighter and the treble control will work more consistently, but it won't be able to cut to quite as low a frequency as it does in parallel mode.

[dougle]

Mar 12, 2018 17:52:08 GMT -5 Yogi B said:

..the only change I'd make is to move the grounding of the neck half of the treble control to happen via the series/parallel switch. This has less caveats than usual since both halves of the control work simultaneously, but I'd still change it.

Thanks for the suggestion. Can you confirm exactly where to connect the ground and what it will do to the circuit?

Do you mean connect the ground end of each of the 2 cap to the black wire (ie middle right) of the parallel / series switch?

-- would that not make it permanently connected in parallel to the neck pup black (gnd) wire -- does this have a different impact than connecting it straight to ground like I have it current draw out-- ie would the bled off high frequencies not just circulate back around the neck pup? ---if so does it hit some sort of saturation and get forced to ground anyway?

--- when set to series the will the bled off treble from the neck would have the option to go to ground via the bridge treble cap? -- if so is it the case that then these two capacitors in series act like one capacitor with a smaller capacitance (eg 33nf -> 33nf = 16.5nf) (?) and thus increase the cut off frequency for the neck pup? -- hence the bright sound you mention

You don't happen to know a good resource to learn the basics of electrical circuits in the context of sound do you?  -- Im currently struggling to match some of the basic electrical rules I've read with the intuitive analogy of water running through pipes especially when then accounting for AC and different frequencies...

[b4nj0]

Yamaha's "Sound Reinforcement Handbook" is my bible, and good value too if you don't splash out on the first eBay hit.

e&oe...

[Yogi B]

Mar 18, 2018 13:24:40 GMT -5 dougle said:

Do you mean connect the ground end of each of the 2 cap to the black wire (ie middle right) of the parallel / series switch?

Yes.

would that not make it permanently connected in parallel to the neck pup black (gnd) wire

Yes. Note that the bridge half of the treble control is already permanently connected in parallel to the bridge pickup. The issue is that (as currently drawn) the neck half ends up being in parallel with both pickups in the series position.

does this have a different impact than connecting it straight to ground like I have it currently drawn out

In parallel mode it will make no difference, the caps are still ultimately connected to ground -- just via the switch rather than directly.

would the bleed off high frequencies not just circulate back around the neck pup? ---if so does it hit some sort of saturation and get forced to ground anyway?

It's not really about letting the treble frequencies go to ground but rather shorting them out. Usually (with a master tone and master volume) they're basically the same thing from different points of view, but not with individual volume controls (particularly in series mode). Instead of doing it globally, we need to it locally for each pickup.

when set to series will the bleed off treble from the neck would have the option to go to ground via the bridge treble cap?

As I say it's not about grounding, and in fact if it were acting alone the bridge treble cap would actually act to increase the treble output from the neck pickup. It provides treble frequencies with a lower impedance route around the bridge pickup, in a similar manner to how the bass control works.

That is to say, if the two halves of the treble cut were on separate controls and you were to have one on full treble and lowered the other, the treble of one pickup is preserved and even accentuated slightly whilst the treble of the other is reduced. Thus the result would be more of an upper mids scoop -- some people like this behaviour other's don't. In your case it doesn't matter since both halves are simultaneously controlled by the same knob -- this situation never occurs.

is it the case that then these two capacitors in series act like one capacitor with a smaller capacitance (eg 33nf -> 33nf = 16.5nf)

Yes, but that's mainly going to have its impact on the sound with the treble set quite low.

and thus increase the cut off frequency for the neck pup? -- hence the bright sound you mention

That's across the entire range of the treble control, for both pickups: the neck half would only be cutting the treble of the neck pickup, rather than both pickups.

You don't happen to know a good resource to learn the basics of electrical circuits in the context of sound do you? -- I'm currently struggling to match some of the basic electrical rules I've read with the intuitive analogy of water running through pipes especially when then accounting for AC and different frequencies...

Not off hand, though b4nj0's already made a suggestion. However hopefully the following will help though.

A way to think about AC that avoids thinking about the current actually alternating direction, is to think of frequency as the viscosity (runniness) of the fluid. The rest of the analogy should still hold, but now you can think of capacitors as filter paper or a mesh. Runnier fluids (higher frequencies) will pass through with ease, thicker fluids (lower frequencies) will struggle. A solid (Constant DC) won't pass at all.

I can't think how to extend that analogy to inductors, but they basically work in exactly the opposite way.

I'd say one of the more important things about understanding AC is that the same rules governing DC potential dividers (using resistors) also applies when introducing capacitors and inductors. It's just that their impedance varies with frequency, whereas the impedance of resistors doesn't. (That's also the basis as to why 50's wiring doesn't work very well works the way it does.)

[dougle]

Great thanks for taking the time to walk me through it. Im sure some background reading will help a lot in understanding it fully. In the meantime I'll wire it up as suggested.

Actually, I'm in the middle of soldering everything together... taking ages (first time) but hoping to finish tonight.

I've currently got the P-rails / triple shots wired up to the old wring in the Epi -- looks and sound really good imo, and far more "musical" / clear than the stock pups :-)

Confirmed that my neck pup rail coil had been wired / cabled incorrectly at the factory and so was giving me an out of phase with P90 of the same pup as well as out of phase with the bridge... At least I learnt how to use a multimeter for testing phase.... it had me really confused for a while as I didn't realise that if you hold the metal object more than about 2-3cm away it actually returns the opposite direction of voltage than when up close to the pup.

I decided to put the higher cap values on the bass tone pot for the bridge than the neck -- 1) because the bridge tone is thinner anyway and 2) because I was concerned that when the 2 pups are in series the two bass caps would work in series resulting in half the cap value and cutting too much of the mid frequency. I want to reduce up to around the 300hz but limit the reduction of 800hz (based on my fiddling about today with the EQ)... lets see... right back to it..

[dougle]

well I built and installed the wiring per the diagram except
1) better tone cap a la guitarnuts2.proboards.com/thread/5317/treble-bleed-circuit
2) moved the neck treble caps to terminate at the middle right lug on the series/parallel switch
2) used slight different cap value for the tone in the neck vs the bridge

However, something is definitely not right ... I've spent hours trying to figure it out but the only outcome is that now I'm knackered.

Issues:
1) vol nobs were dependant on each other when the 3 way is in the middle -- I've changed this by flipping the output and inputs on the vols
1a whilst in "depedant mode" the tone controls were doing strange things: working  in one direction, not working, working in reverse direction  depending on the setting of the 3-way switch

2) the neck at full volume is around 1/3rd of the full volume of the bridge

3) the neck tone sounds like it has had the bass taken out of it and also the bass control has no noticeable effect

4) the bridge tone is dull like it has had the treble cut also is quite nasally and the treble control doesn't work when set to the bridge

I've checked the wiring many times and it all seems to be going between the points in the diagram.

I started trying to diagnose by removing the caps for the bass and treble from the neck side in case there was a problem in the connections in the tone pots--- nothing was improved it still had a has very low volume (sounds less than half of the bridge vol) and has a very thin sound (lacking in bass)

I also thought i might have to do with the treble bleeds -- I've not disconnected them yet as they were a pain to put in given all the clutter and size of the components

Any ideas as to what might be causing it? -- or what tests I can perform to diagnose the issue?

[JohnH]

Im sure you will get it going. If the problem is not clear, then a set of resistance tests might flush out the gremlins. Measure across output and ground in each switch setting combination, with all volumes and tones at max. You should be able to measurw close to pickup resistance in single modes, and the sum in series and less in parallel (ie about x1/2 with equal pickups). Phase should not affect the reading. Also your tone switches, which just switch caps? should not affect resustances.

Turning the bass cut pot should increase resistance at reduced bass. Treble cut pot should not affect it if turned.

[dougle]

Thanks for the support. After lots of resistance testing etc it turns out it was two bad connects to ground causing some pretty strange effects. So I think it is now all done. All seems to be working as expected and looks rather neet if I do say so myself (seems almost a shame to lock all the wiring out of sight. There are so many variants of selectable tones that I've only had a chance to play with a few so far but somethings already standout...

1) the setup is super loud vs my old setup - so much so that it is causing some issues with distortion and what sounds like clipping even with the gain on my interface set at minimum.... good the I can actually use the vol controls :-)

2) the treble pot final has a purpose - I find myself using the 15nf cap most

3) putting switchable caps probably was overkill-- using one vs the other doesn't seem to make that much difference until you get to all most max treble cut and I don't really use that range -- but maybe it will become more useful as I get to know the setup better

4) the bass control is pretty hand and is working well. time will tell if I'll miss having seperate treble controls but if I do might make a basscut switch with the push-pull instead

5) I've found some very distinct and nice tones already though all this focus on tone has made me think I should get a tube amp :-)

6) the treble bleed sounded like it was working but for the neck pup the treble and "presence" frequencies seemed like they were still rolling off with volume reduction. Just to see how it would be I cut the resistor on the neck bleed to be left with the most basic setup of a 1nf cap in parallel and no resistor or connection to the 2nd gang  -- to my surprise, it seems to work very well.. If I can find a suitable program on the ipad ill check the frequency response at different volumes out of curiosity

thanks again for all the help!

[dougle]

Hi, Well its all working aside from the blending of the pups - so I have one last remaining challenge --- because I've reverse wired the vols for independance - when the 3way is set to both, whichever vol is reduced acts like a treble tone control on the signal from the other pup via the 1nf treble bleed. So instead of blending it is blenind plus darkenning -- it results in a few nice tones but I rather just blend and save the treble reduction for the treble control

..The only solution I can think of working well is fitting an active buffer...

...will this work with independent (backwards wired) vol pots ?? and if so where in the circuit would it need to fit? --- my concern is as follows:

---I've got the jist that is the RLC (and resonance) of the pups and interaction with the resistance in parallel with the rest of the system that is causing frequency loss.... It struck me that with the vol at just above zero when using reverse vol pot wiring that the resistance in parallel is going to be pretty low even if one puts a high impedance buffer at the jack and that puhaps the buffer would then need to come before the bass and vol pots?

 -- if so would the buffer need to vary its output to compensate for the vol nobs position and how would it work with two volume nobs?

[reTrEaD]

Hi dougle

Reverse wired volume pots bring more problems than they cure. I wouldn't use them. Ever.


JohnH has a partial fix for decent blending with separate volumes (wired forward). You should read this thread, starting from the post this links to: guitarnuts2.proboards.com/post/84076/thread (We should probably talk John into adding that circuit to Design Modules or granting his blessing for another member of the GN2 team to do so.)

If that's enough of a cure, it makes more sense than an active buffer since there's no need for a battery and the added complications. But, if you must be able to turn either control to zero when both pickups are selected, an active buffer would probably be worth doing.

There's no need for reverse wiring with a properly designed buffer. The inputs are isolated so there will be no interaction of one volume control on the other side of the circuit. Also, since the volume controls are feeding a high impedance circuit with no cable capacitance complicating things, treble bleed networks will not be used on the volume controls.

[dougle]

Mar 22, 2018 22:18:09 GMT -5 reTrEaD said:

Hi dougle

Reverse wired volume pots bring more problems than they cure. I wouldn't use them. Ever.


JohnH has a partial fix for decent blending with separate volumes (wired forward). You should read this thread, starting from the post this links to: guitarnuts2.proboards.com/post/84076/thread (We should probably talk John into adding that circuit to Design Modules or granting his blessing for another member of the GN2 team to do so.)

Thanks a lot. I bought this guitar in '92 new (had a long break from playing) and it came wired in reverse so the effects of that were the norm for me and I never thought other people had a different design as standard... so when I had the initial issues after rewiring it all I was pretty shocked by the dependence of vols and thought this was the route of all the issues and flipped it.... bugger .. I'll change it back in that case and try the 10k res to acts as a separator

hmm is the reverse wiring loading up the pups so much at lower vol that it cus the treble more than with forward wiring? -- it may explain why using a 1nf without a resistor works pretty well whereas a more conservitive approach was still very muddy when rolling off vol even when using a 3ft cable into a high z input

[reTrEaD]

When a volume control is wired in reverse, it's pretty much useless as a volume control. Especially when one pickup is used alone. Without the voltage division inherent in the normal wiring, it muddies up the tone immensely before any significant reduction of volume occurs. When both pickups are selected together, reverse wiring does an okay job of blending. And you can even reduce the contribution of one pickup down to zero without any tonal degradation of the other pickup which has its volume at max. But that small benefit is severely outweighed by the fact that you can't reduce the overall volume without getting muddy.

The resistor placed in parallel with the treble bleed cap does a nice job of mitigating the overcompensation which normally accompanies the capacitor-only treble bleed. If your volume control acts more like a treble-cut, overcompensating is a good thing.

[JohnH]

The forwards wiring is much better in almost every way, except if you choose to turn one pickup way down while both are on. But if you do that, that 'off' pickup is almost not providing anything, so you might as well have used the switch to choose the pickup that you want.

The treble bleed recipe of 1nF+150k in parallel is designed for forwards wiring, and of all the volume and treble bleed arrangements that we know of, it is the best simple one if you want consistent tone.

The module referred to above with the separating resistors was offered for an application where the control of mixing two outputs (necks, or pickups) was critical to the application. If you are also deeply into subtle mix control of pickups, then it might help. Doesn't hurt to try it. There were 4 parts to the idea: treble bleed whereby the resistor is also helping reduce the pot taper, use of linear pots, use of 250k instead of 500k pots, and the 10k resistors. They can be mixed and matched. With all of them together as used on the doubleneck, mixing is very smooth but some would find the volume action too slow when turning down one pickup on its own.

With the 'problem' of one volume turning both off, the best solution IMO is not to regard it as a problem, since the settings that it occurs at are not very useful anyway.

Buffers are interesting mini-projects and I built a few into guitars. They do change the tone tough, adding presence and making the guitar cord less dominant in affecting treble. I like them in some cases but its hard to preserve the classic tone of a good passive alnico pickup with basic wiring feeding directly via a good 10' cord into a great tube amp.

[dougle]

Thanks to both of you. 

Agree ref forward wiring - it just surprised me initially

Ive got it all wired up (with forward vols now). The two treble bleed circuits with variable series and parallel resistors plus the extra series resistor for separation are wired temporarily outside of the guitar so I can easily change configurations and test the impact and I've been through lots of testing and agree the 1nf 150 when going through the 10m is a winner, also the 0.82nf and 100k with the 2nd gang the second gang is good as well as 250k +2gang + 1nf and using 10k in serieS with cap. In part I wanted to see how each component was effecting the frequency curve and get a better understanding for manipulating the tone.

However after all that I thought I'd try making a very short lead to plug into my irig hd2 which has a 1m or 2m input ( I think ).... it sounded really good for clean sounds using the p-rails when split. With this set up the treble bleed added too much treble and to me didn't seem necessary (although some times sounded pretty good - albeit different)...So I think I'll just stick it all on a small perf board with a switch and reeval after I've had a chance to play for a while without wires sticking everywhere.

the 10ks for separation didnt seem to make much difference with the longer cable set up though I may check again using 100k 0.82nf plus second gang option.  Playing though the short lead into the irig did seem to help the blending but i still felt the interaction between the pups may be muddying the tone a little when mixed but it's hard to know for sure...anyway blending is a nice to have for me so I might try some bigger separating resistance and if that doesn't improve things enjoy it just as is

the pots are audio taper and I'm not much of a fan -  maybe I'm strange but they do not follow my perception of volume at all. To me they sound like they have a massive effect from 10 to 7 vs 7 to 4 and so I suspect I would prefer linear for vol. I like the audio taper for the tone controls as I just use down to around 5 or 6 anyway...also a little different but I think I prefer to have much small value caps and might try a 8nf or something to go with the 15nf for the treble as even the 15nf eats into mids quite a bit. Can't really understand how people use 47s..

Hmm yes a tube amp is on the shopping list....I'm very impressed by how far things have come and what I can get via an irig and AmpliTube 4 into the iPad -clean sounds very good at times, so does thrash metal distortion (although not so much my thing anymore) but i can't get a good point of breakup crunchy blues/rock tone it's like is cutting in and out with some weird digital artifacts in the higher frequencies 

[reTrEaD]

Mar 25, 2018 20:50:17 GMT -5 dougle said:

the pots are audio taper and I'm not much of a fan -  maybe I'm strange but they do not follow my perception of volume at all. To me they sound like they have a massive effect from 10 to 7 vs 7 to 4 and so I suspect I would prefer linear for vol.

Audio taper works great for a volume control in a one-volume configuration. But when we tie the two wipers together in a two-volume configuration with both pickups selected, the situation changes. If smooth blending is of greater importance than the action of the volume control when one pickup is selected, your suspicions are correct. You will prefer a linear, even though it's not quite right in the one-pickup only selections.

Pickups/controls in-parallel means compromises. You'll never get everything right in all selections. But if you know what does what, you can make changes the bring you a little closer to a compromise that suits you.

The 10k separating resistors are a nice patch but there's a limit to how much they can do. You might try increasing the value slightly but a larger value will mean more high frequency loss due to the cable capacitance.

Treble-bleed networks are a patch to mitigate the high-frequency loss due to the inherent RC filter which is comprised of the cable capacitance and series resistance when a volume control is rotated CCW from max. Using a cable that is of better quality and shorter length means significantly lower capacitance than the value around which the treble-bleed was designed. Overcompensation in that case follows normal expectations.

[boctok]

Mar 12, 2018 10:08:41 GMT -5 dougle said:

I've had a go at changing the wiring (as follows) to address the issues mentioned:

- moved the tone pots upstream of the vol pots so they are more effective and used the 2nd gang to ensure that the vols are not permanently connected
- changed to series/parallel switch so that it works on any of the 3-way selector switch settings
- corrected the naming of the vol pots

I've followed the path and all seemed to check out but would appreciate a 2nd pair of eyes before I start installing it ... well, that is when the parts arrive - they somehow ended up in Lisbon (from the UK) even though I live in Spain...




Diagram Notes: --
Colours
Red - input neck vol
Yellow - output neck vol
Blue - input bridge vol
green - output bridge vol
Brown- ground
orange- output to jack
Black - other

caps are not connected together although it may seem like that in the diagram
gaps in wires represent where they cross other wires
Treble bleeds omitted from the diagram - for simplification -  but intend to try a small trim resistor in parallel to a cap between input and output lugs of each the vol as suggested

Thanks again,
Douglas

I'm sort of confused by the graphic. Are those tone pots supposed to be concentric pots, or was it just done that way to make the wiring connections easier to see?

[sumgai]

May 10, 2018 9:06:51 GMT -5 boctok said:

Mar 12, 2018 10:08:41 GMT -5 dougle said:

I've had a go at changing the wiring (as follows) to address the issues mentioned:

- moved the tone pots upstream of the vol pots so they are more effective and used the 2nd gang to ensure that the vols are not permanently connected
......

I'm sort of confused by the graphic. Are those tone pots supposed to be concentric pots, or was it just done that way to make the wiring connections easier to see?

The answer is yes, they are concentric pots per the bullet point as quoted.

[boctok]

Where does one find a stacked, push-pull pot? I've never seen one with both functions.


Never mind, I checked the repository of all things known and unknown. Sure enough, there they were.


www.amazon.com/Bourns-Guitar-Potentiometer-Switch-Audio/dp/B005G05SCY

[reTrEaD]

May 10, 2018 9:06:51 GMT -5 boctok said:

I'm sort of confused by the graphic. Are those tone pots supposed to be concentric pots, or was it just done that way to make the wiring connections easier to see?

I don't believe they are. I think they're Dual Gang pots which is a slightly different animal.

Dual Gang (one shaft controls two elements synchronously)





Concentric (one shaft inside the other, each controlling an independent element)



The pot in your most recent link is a Dual Gang with push/pull switch. And that's likely the variety of pot dougle will be using.

[johnwestt]

I like what you have done here with the schematic.  I own a 2021 Classic and the 4-knobs are mounted to a circuit board,  I would really like to have a volume control capability when you pull out the bridge tone knob into the "By-pass" mode.  Any Ideas on doing this?  Wes