Trimpot suggestions for coil splitting

Hi,

I love my 94 PRS CE24.  The rotary switch has long gone in favour of a traditional 3-way switch and a push/push tone pot to split the humbuckers.

But the coil split is a bit extreme volume wise.  So I'm thinking of sticking a resistor between the split and ground / hot to preserve a bit of signal of the coil that is normally cut.  One of the HBs cuts to hot, one to ground.

I've done this before on a previous guitar and it worked well.  I think I used roughly 1.6Kohms of resistance, but it was a long time ago and different pickups; the PRS HFS and VB pickups are very hot.

Because the exact value on the resistor is difficult to really get until playing at live volume in a variety of circumstances I'm thinking I'd like to have a mini PCB with screw terminals between the tap wire and live/ground (depending on the HB, and then a couple of trim pots.  Maybe a 2k, 5k and 10k available for each pickup.....then I can wire it up.....and tweak via the dial on each and find what works.

And one of my terrible 'logical' rather than physical mock ups to explain the idea....I guess I'd try to use the PCB tracks to run to the trimpots but I don't really know.  



But I have almost no build experience, and although I can see the individual components on Amazon and eBay, none confirms whether the terminal spacing is compatible with a particular PCB etc so looking for advice there.

I'm think I need :

A PCB of roughly 3cm by 6cm
8 two wire screw terminals - 1 for each HB split wire, and then 1 in front of each trimpot per pickup
2 x 2k, 5k and 10k trimpots (so I have each trim pot available for each HB)

But I'm bound to have missed something or there is an easier way.

Please let me know what you think.

Cheers,
Andy

The whole point of trimmers is that you only need one! (For each pickup.) All you need to do is pick one with slightly more range than you actually need.

PRS uses fixed resistors of 1.1K for the neck pickup and 2.2K for the bridge - and I’m sure they arrived at those after a lot of testing - so if you used 2.2K for the neck and 4.7K for the bridge, that would put the PRS values right in the middle and give plenty of adjustment above and below.

andyg_prs said:

the PRS HFS and VB pickups are very hot.

c. 14½ and 9k, respectively, IIRC.

ICBM said:

PRS uses fixed resistors of 1.1K for the neck pickup and 2.2K for the bridge 

I have precisely those values in my S2 Singlecut - designed to work with its stock 8/9k humbuckers. They also worked well with Oil City Pickups Scrapyard Dog Plus and Nightfighter 4 humbuckers.

Thanks - it's hard to find individual components at a reasonable price. 

This kit has 2k and 5k trimpots.

And this seems to have the pcbs and screw terminals....would that do it?

Maybe I'm being a bit dim and am missing something, but do you even need the PCBs? I fitted trimpots to a couple of my guitars and all you really need is the trimpots (and maybe a little bit of wire since that's easier to solder to the push-pull bit of the pot). It might not be the most elegant solution, but it did work!

It really depends on the pickups and your preferences, but I found on a few guitars that 5k wasn't enough for some bridge pickups- 10k gives you a bit more leeway, but obviously gives you a bit less fine control for really dialling it in. I'd be inclined to go for 10k bridge, 5k neck, but that's just me. As I said, though, it's really dependent on the individual pickups... some neck pickups especially need very little resistance to sound right. EDIT: And according to @Funkfingers those pickups are fairly hot so @ICBM is probably right with his suggested values.

Dave_Mc said:

Maybe I'm being a bit dim and am missing something, but do you even need the PCBs? I fitted trimpots to a couple of my guitars and all you really need is the trimpots (and maybe a little bit of wire since that's easier to solder to the push-pull bit of the pot). It might not be the most elegant solution, but it did work!

It really depends on the pickups and your preferences, but I found on a few guitars that 5k wasn't enough for some bridge pickups- 10k gives you a bit more leeway, but obviously gives you a bit less fine control for really dialling it in. I'd be inclined to go for 10k bridge, 5k neck, but that's just me. As I said, though, it's really dependent on the individual pickups... some neck pickups especially need very little resistance to sound right. EDIT: And according to @Funkfingers those pickups are fairly hot so @ICBM is probably right with his suggested values.

I'm a klutz, and not the best at soldering.....and the PRS wires are very thin.....so I figured, if I solder everything on a small PCB, secure it somewhere safe in the control cavity and only have to feed in the pickup wires.....that gives me the best chance of a set up that will last (and not fail during a gig) and be robust enough for me to tweak the resistance on the fly.

andyg_prs said:

Dave_Mc said:

Maybe I'm being a bit dim and am missing something, but do you even need the PCBs? I fitted trimpots to a couple of my guitars and all you really need is the trimpots (and maybe a little bit of wire since that's easier to solder to the push-pull bit of the pot). It might not be the most elegant solution, but it did work!

It really depends on the pickups and your preferences, but I found on a few guitars that 5k wasn't enough for some bridge pickups- 10k gives you a bit more leeway, but obviously gives you a bit less fine control for really dialling it in. I'd be inclined to go for 10k bridge, 5k neck, but that's just me. As I said, though, it's really dependent on the individual pickups... some neck pickups especially need very little resistance to sound right. EDIT: And according to @Funkfingers those pickups are fairly hot so @ICBM is probably right with his suggested values.

I'm a klutz, and not the best at soldering.....and the PRS wires are very thin.....so I figured, if I solder everything on a small PCB, secure it somewhere safe in the control cavity and only have to feed in the pickup wires.....that gives me the best chance of a set up that will last (and not fail during a gig) and be robust enough for me to tweak the resistance on the fly.

You may be right- I always figured PCBs would be more awkward to solder, but I might be wrong about that (I'm terrible at soldering!). Not failing during a gig is a good idea- I only play at home, so I tend to forget about that, sorry about that. If my wiring fails, it's annoying but not catastrophic. :)

Dave_Mc said:

andyg_prs said:

Dave_Mc said:

Maybe I'm being a bit dim and am missing something, but do you even need the PCBs? I fitted trimpots to a couple of my guitars and all you really need is the trimpots (and maybe a little bit of wire since that's easier to solder to the push-pull bit of the pot). It might not be the most elegant solution, but it did work!

It really depends on the pickups and your preferences, but I found on a few guitars that 5k wasn't enough for some bridge pickups- 10k gives you a bit more leeway, but obviously gives you a bit less fine control for really dialling it in. I'd be inclined to go for 10k bridge, 5k neck, but that's just me. As I said, though, it's really dependent on the individual pickups... some neck pickups especially need very little resistance to sound right. EDIT: And according to @Funkfingers those pickups are fairly hot so @ICBM is probably right with his suggested values.

I'm a klutz, and not the best at soldering.....and the PRS wires are very thin.....so I figured, if I solder everything on a small PCB, secure it somewhere safe in the control cavity and only have to feed in the pickup wires.....that gives me the best chance of a set up that will last (and not fail during a gig) and be robust enough for me to tweak the resistance on the fly.

You may be right- I always figured PCBs would be more awkward to solder, but I might be wrong about that (I'm terrible at soldering!). Not failing during a gig is a good idea- I only play at home, so I tend to forget about that, sorry about that. If my wiring fails, it's annoying but not catastrophic. :)

From memory, there is sufficient room in terms of depth, to position the board on the flat of the back of the pots.....on a decent strip of some insulation of course.....that'll make it a breeze to adjust mid rehearsal.

I still remember having a JVM410H upside down on a velvet curtain, and soldering in different value components between songs with one of my bands years back - utter madness! :)

With my reading vision gone.....and the tiny wires on PRS pickups, no way I could do that these days....

I've not heard back on those links @ICBM  - do these seem to be reasonable components that should fit together ok?

"This kit has 2k and 5k trimpots.

And this seems to have the pcbs and screw terminals"

andyg_prs said:

Dave_Mc said:

andyg_prs said:

Dave_Mc said:

Maybe I'm being a bit dim and am missing something, but do you even need the PCBs? I fitted trimpots to a couple of my guitars and all you really need is the trimpots (and maybe a little bit of wire since that's easier to solder to the push-pull bit of the pot). It might not be the most elegant solution, but it did work!

It really depends on the pickups and your preferences, but I found on a few guitars that 5k wasn't enough for some bridge pickups- 10k gives you a bit more leeway, but obviously gives you a bit less fine control for really dialling it in. I'd be inclined to go for 10k bridge, 5k neck, but that's just me. As I said, though, it's really dependent on the individual pickups... some neck pickups especially need very little resistance to sound right. EDIT: And according to @Funkfingers those pickups are fairly hot so @ICBM is probably right with his suggested values.

I'm a klutz, and not the best at soldering.....and the PRS wires are very thin.....so I figured, if I solder everything on a small PCB, secure it somewhere safe in the control cavity and only have to feed in the pickup wires.....that gives me the best chance of a set up that will last (and not fail during a gig) and be robust enough for me to tweak the resistance on the fly.

You may be right- I always figured PCBs would be more awkward to solder, but I might be wrong about that (I'm terrible at soldering!). Not failing during a gig is a good idea- I only play at home, so I tend to forget about that, sorry about that. If my wiring fails, it's annoying but not catastrophic.

(a) From memory, there is sufficient room in terms of depth, to position the board on the flat of the back of the pots.....on a decent strip of some insulation of course.....that'll make it a breeze to adjust mid rehearsal.

(b) I still remember having a JVM410H upside down on a velvet curtain, and soldering in different value components between songs with one of my bands years back - utter madness!

(c) With my reading vision gone.....and the tiny wires on PRS pickups, no way I could do that these days....

(a) Yeah that would probably help. I just have mine stuffed in the cavity, it can make it hard to get at them- luckily I just tend to set and forget, I spent a while when I first fitted them dialling them in perfectly, and then just left them.

(b) LOL!

(c) Ah that sucks, I've been shortsighted since I was a child, but since getting older (I'm not that old, I noticed it starting happening in my late 20s I think) I can't really see up close with my glasses on any more, I have to take my glasses off to see stuff up close. There's a bit of an annoying distance where it's too far away for my eyes, but too close for my glasses (about arm's length), lol.

andyg_prs said:

do these seem to be reasonable components that should fit together ok?

"This kit has 2k and 5k trimpots.

And this seems to have the pcbs and screw terminals"

Well… yes, but those are crazy quantities to buy when you need two trimmers and at most a bit of stripboard.

ICBM said:

andyg_prs said:

do these seem to be reasonable components that should fit together ok?

"This kit has 2k and 5k trimpots.

And this seems to have the pcbs and screw terminals"

Well… yes, but those are crazy quantities to buy when you need two trimmers and at most a bit of stripboard.

I miss Maplins :)

You can buy single components on Ebay very easily. Even with postage added it’s still cheaper than buying a hundred times as many as you need.

Yes, it's about £9 for a single 2k, 5k trimpot, and one piece of PCB and 2 screw terminals and £18  (just got that down to £16) for the assorted pack which has much more than I currently require.  But by the time I add in a couple of extra components in case I muck something up, or want to try a trimpot of a different value, then it's almost the same.  And I have stuff left over for other guitars or future experiments.

Of course, I'd buy a far smaller kit if I found one.  All good though

andyg_prs said:

ICBM said:

andyg_prs said:

do these seem to be reasonable components that should fit together ok?

"This kit has 2k and 5k trimpots.

And this seems to have the pcbs and screw terminals"

Well… yes, but those are crazy quantities to buy when you need two trimmers and at most a bit of stripboard.

I miss Maplins :)

Hi-De-Hi, campers.

Funkfingers said:

Hi-De-Hi, campers.

Hi Gladys!

MARVlN said:

I really like BitsBox for this kind of stuff. Much more set up for amateur parts volumes than Farnell et al, well priced and they do guitar bits too.

Trim pots:

https://www.bitsboxuk.com/index.php?main_page=index&cPath=94_95_319

Not connected to them BTW.

I'd already ordered, but that would have been a third of the price!  A very useful site which I'll bookmark and definitely take a good look through - thank you!

MARVlN said:

I really like BitsBox for this kind of stuff. Much more set up for amateur parts volumes than Farnell et al, well priced and they do guitar bits too.

Trim pots:

https://www.bitsboxuk.com/index.php?main_page=index&cPath=94_95_319

Not connected to them BTW.

Thanks for the link - it's always good to have a choice of suppliers.

On another note (and I know this could be a can of worms). 

When I've tried resistors before, the higher the resistance, so the more of the second coil that is retained (to minimise the volume drop on the coil split), the 'single coil-ish' nature of the sound decreases....because of course, you have more of the second coil still in circuit.

Is there any wisdom in terms of how a capacitor could some how allow the bassier frequencies through, retaining the higher frequencies for that single coil effect?  And is there any resistance vs capacitor value to consider in this?

And how would the capacitor be wired in with the trimpot please?

I tried a 10k trimpot for a partial tap on the bridge humbucker on my bitsa Jazzmaster (old Duncan Jazz Bridge pickup, low wind single coil neck pickup). Despite reading everywhere that values of around 1-3K are typically used, I liked it best right up at 10k, and swapped it out for a 10K resistor instead. Perhaps because the Jazz Bridge is pretty bright for a humbucker. The 10k partial tap is a fun sound that I use a lot on that guitar - it's like a tele bridge with hints of strat position 2.

Yup, my first attempt with trimpots - 2k for the neck and 5k for the  bridge, I good barely discern the difference when turning the dials.  I've used 10k for both and in my bedroom seems to have the range I need.....but need to get it on my proper rig.

I'm now looking for treble pass (or is it bleed?) capacitor values as the sound is obviously beefier with 1 and a bit coils in circuit.....so I want to lose more bass / preserve more treble when I coil split.

I might start a new thread as I think people may have lost interest here :)

andyg_prs said:

Yup, my first attempt with trimpots - 2k for the neck and 5k for the  bridge, I good barely discern the difference when turning the dials.  I've used 10k for both and in my bedroom seems to have the range I need.....but need to get it on my proper rig.

I'm now looking for treble pass (or is it bleed?) capacitor values as the sound is obviously beefier with 1 and a bit coils in circuit.....so I want to lose more bass / preserve more treble when I coil split.

I might start a new thread as I think people may have lost interest here :)

Not lost interest, I just haven't tried caps so I can't help!

Dave_Mc said:

andyg_prs said:

Yup, my first attempt with trimpots - 2k for the neck and 5k for the  bridge, I good barely discern the difference when turning the dials.  I've used 10k for both and in my bedroom seems to have the range I need.....but need to get it on my proper rig.

I'm now looking for treble pass (or is it bleed?) capacitor values as the sound is obviously beefier with 1 and a bit coils in circuit.....so I want to lose more bass / preserve more treble when I coil split.

I might start a new thread as I think people may have lost interest here :)

Not lost interest, I just haven't tried caps so I can't help!

There was no slight intended....everyone's been great.....more to the point, a new more targeted post is more likely to get a response :)

Sorry, I missed the question. Replied on the other thread :).

andyg_prs said:

Dave_Mc said:

andyg_prs said:

Yup, my first attempt with trimpots - 2k for the neck and 5k for the  bridge, I good barely discern the difference when turning the dials.  I've used 10k for both and in my bedroom seems to have the range I need.....but need to get it on my proper rig.

I'm now looking for treble pass (or is it bleed?) capacitor values as the sound is obviously beefier with 1 and a bit coils in circuit.....so I want to lose more bass / preserve more treble when I coil split.

I might start a new thread as I think people may have lost interest here :)

Not lost interest, I just haven't tried caps so I can't help!

There was no slight intended....everyone's been great.....more to the point, a new more targeted post is more likely to get a response :)

No worries, I didn't mean to suggest it was a slight, just letting you know as it's hard to know on a forum whether you're being ignored, people have just missed it or people just don't know!

I'm keeping an eye on your new thread with interest, though I can't add anything myself :)