HSS Treb-Mid-Bass control + Spin-a-split (Wiring advise)

[mgmog]

Hi to Guitarnuts community,


First of all, thanks for this forum! It’s pretty hard to get information about guitar mods in France and this kind of website doesn’t exist there…or I didn’t find it yet!!

(And also, be kind with my poor English, I do my best without using translator…maybe I should!! )

Few years before, I rewired my SSS Lite ash Stratocaster in “normal way” (I just changed my bridge pickup by a SD hotrail) and I found it really interesting. So now, since few month, something grew up in my head… then I started to look after different “new” possibilities/mods I can work on it to improve my knowledge.

After my research, and reading A LOT of different topics on different platforms, I started to thinking about an HSS wiring using a “standard” humbucker, a Freeway-switch 10Way, PTB, midrange control and a spin-a-split for the humbucker.

I based my scheme on those link and pictures I found:

- Basic Free-way switch scheme: www.freewayswitch.com/schematics-blade/
- G&L PTB wiring:

- Rothstein midrange control: www.guitar-mod.com/rg_passive.html
+ a drawing I found somewhere…

- Spin-a-split: www.seymourduncan.com/blog/latest-updates/guitar-wiring-explored-the-spin-a-split-mod
- Pots mods: www.geofex.com/article_folders/potsecrets/potscret.htm


Then, I drawn this “try” as a first shot:
 

Now, the big question is… Do you this idea can work??

And without thinking about mistake I made on my wiring, I still have questioning about pots…

- Do you think is possible to make two dual concentric pot ,500k/25k and 500k/1M with two “normal” 500k/500k concentric pots, one 1M pot and one 25k pot?
- According to “The secret life of pots”, it’s also possible de convert a 1M LIN pot to a 1M LOG REV pot using a resitor…but it’s still working with a capacitor in parallel?


I hope I was pretty clear… Happy to get your help and I’m curious to see your answer!


Have a good day

[newey]

mgmog-

Hello and Welcome to G-Nutz2!

At work at the moment, so I don't have time to check the diagram. But your link to the Freeway diagram just takes me to the page listing all the Freeway wiring diagrams, so I don't know which one you used. Best would be if your diagram liste the 10 combinations on that switch.

Also, why would the midrange control use a 25K pot? The link to Rothstein's site you provided says they use 500K.

[mgmog]

No problem! Netheless, thanks for the interest

About Free-way switch scheme, yes I saw that... but for wiring the switch, I use 2 diagram from them:

- This one: SSS wiring with PTB


- And this one: HSS with a normal push pull split


And for the 25K pot, this is not for the midrange control but for the spin-a-split pot.

[JohnH]

hi mgmog

Welcome to GN2, A few comments on some parts of your design:

For the midrange control, it may tend to affect the tone at all settings, ie, you can't set it to completely off and get the tone as it was not there, unless there's a switch for it. The PTB controls are good, when they are at max it's as if they are like a normal simple tone control.

25k, modified by you for no-load is a good value for spin-a-split. Most of the affect is in the first few k, and when you get to max 25k, there'll just be a very small step in tone as it goes out of circuit.

It's not possible to create a proper log taper with a linear pot and a resistor for most guitar uses. The resistor makes the overall pot value effectively change as you turn it. It can work ok in an active circuit like a mixer, where this variation is acceptable. But it can't do what we usually want a log pot to do which is start at zero resistance, have a low resistance at mid-turn and then a max very high resistance at full turn.

On the dual pots. I think you want each pot half to be separately controlled?, ie two knobs on one shaft? if so, that is a dual concentric pot. Dual gang means two pots turned together with one knob.

I've modified a few pots, but I've had trouble with most dual pots, they are often harder to open up and reassemble. It may be possible though, particularly on the outer half. There must be a way, since they were made, they can be un-made. But you'd have to experiment and I've only succeeded with one type, which I couldn't find again Single pots are easy though, particularly the full sized ones.

[mgmog]

Hi JohnH,

Thanks for your comment!

For the midrange control, it may tend to affect the tone at all settings, ie, you can't set it to completely off and get the tone as it was not there, unless there's a switch for it. The PTB controls are good, when they are at max it's as if they are like a normal simple tone control.

Ok, and what about also use there a no-load pot? It should be as a switch at full trottle

It's not possible to create a proper log taper with a linear pot and a resistor for most guitar uses. The resistor makes the overall pot value effectively change as you turn it. It can work ok in an active circuit like a mixer, where this variation is acceptable. But it can't do what we usually want a log pot to do which is start at zero resistance, have a low resistance at mid-turn and then a max very high resistance at full turn.

Hum, that was my concern... It will be really "dramatic" to use a 1Meg or 500K log pot for a bass cut? I saw there: tonefiend.com/guitar/two-band-ptb-tone-control-useful-easy-cheap-awesome/ , it works but maybe not as it should be.

On the dual pots. I think you want each pot half to be separately controlled?, ie two knobs on one shaft? if so, that is a dual concentric pot. Dual gang means two pots turned together with one knob.

My bad! you've right, I was speaking about those "two knobs on one shaft pot" like Jazzmaster.

I've modified a few pots, but I've had trouble with most dual pots, they are often harder to open up and reassemble. It may be possible though, particularly on the outer half. There must be a way, since they were made, they can be un-made. But you'd have to experiment and I've only succeeded with one type, which I couldn't find again Single pots are easy though, particularly the full sized ones.

As you said, It should be a way... I will try! Also, with your feedback on dual pots, do you remember if diameters (outer and inner hole) are the same on both stage?

[JohnH]

Most people think that the ideal taper for a bass cut pot is type 'C', which is a reverse log. Its like a standard log pot but reversed clockwise to anticlockwise. With it, you can turn the knob clockwise to reduce bass cut, similarly to how you turn a treble pot to get less treble cut, the tonal result is fairly smooth. 1M is best to get the most range. Or you can use a standard log pot, wired with outer lug swapped, and now its still smooth but zero bass cut is anticlockwise, and I think you could get used to either direction. Or use a linear pot and you get the same full range, but more concentrated to one end. And sadly, there no way of using a resistor to adjust the pot in this case.

Ive only used dual-ganged pots, with one knob. But I think the dual concentric have two shaft diameters. Maybe look at a picture online.

I dont think a no-load pot will work with the mid control, since its using all three lugs. How about a push pull switch on your volume pot?

[mgmog]

Ok so, according to this picture below, for a bass cut we should have a curve as curve (4), right?
If yes, that will confirm what I saw on manufacturer datasheet. For them (like CTS, Alpha) "C" pot are LOG CCW and not LOG REV.



Nethertheless, I keep in mind normal 1M Log as a solution!

For pots modification, according to this (weird) "video"  
 
it looks possible a least on one side. I'll give a try.

Yes a P/P can be an idea, push=no Mid control and pull= Mid control. But for split mids, you just have to "open" the middle lug? 

[mgmog]

Hi JohnH,

I dont think a no-load pot will work with the mid control, since its using all three lugs. How about a push pull switch on your volume pot?

I was thinking about your answer yesterday and the fact we cannot use a no-load pot for split the Mid control...



All I saw on internet about turning a pot to no load pot, it's people who cut the "carbon track" on the wafer to cut the continuity between outer and middle lug at one moment. It works but also you loose the continuity between outer lug anytime.



So to keep this continuity between outer lug, it's not possible to use something like varnish or epoxy glue for cut continuity with the middle at one moment, without damage the carbon track?

(I hope I was clear )

[mgmog]

Hi,

So I made a little update about my wiring.

It's still too hard to me to find a 1MegC pot so I gonna use a 1Meg audio "classic". I swapped the lugs of my bass cut wafer on my drawing...but I'm not sure of that...

Also I falled on this topic guitarnuts2.proboards.com/thread/5317/treble-bleed-circuit?page=6 from JohnH and I also added  this "Mystery TB" like they says on YT



This being said, if someone have any suggest about my no-load pot using varnish / epoxy glue what I was thinking about on the last post, I'm still interest!