Gut shots of a Sire Larry Carlton S7

BillDL

@MentalSharps ;  I actually found it quite interesting reading the company details from what you copied and pasted, despite my tongue-in-cheek sarcasm.  I usually do exactly as you do, i.e. research companies, but in this instance I have yet to focus my attention on Sire guitars and so haven't yet looked into the company in any detail.  You saved me the bother of going and searching for it all.

Dave_Mc

BillDL said:

@MentalSharps ;  I actually found it quite interesting reading the company details from what you copied and pasted, despite my tongue-in-cheek sarcasm.  I usually do exactly as you do, i.e. research companies, but in this instance I have yet to focus my attention on Sire guitars and so haven't yet looked into the company in any detail.  You saved me the bother of going and searching for it all.

Yep same here

CasperCaster

Dave_Mc said:

That's an interesting point about the resistors- I just assumed the resistors were for the single coils. If it is for the tone pot value as well, that's very cool- I honestly don't know, I've managed to avoid needing a superswitch- apart from the one which came stock in my Ibanez- so far!

That's a good call about the tone caps too, as you said, if you put them in series that would probably work as you said.

I've had a bit of a better look at the gut shots now, and looked through all the images. As stated previously, the bottom left pole of the switch is selecting either a single cap (the one bottom right) or both caps in series such that the bridge selection alone sees a lower effective cap value.

The bottom right pole is selection for the middle pickup and also those parallel resistors (so the single coils see 250K from the 500K volume pot). I initially figured that one resistor would be for the tone pot, but that is incorrect - ALL pickup selections actually see the same pot value for the tone control.  The reason there are two resistors is because that bottom right switch pole is doing double duty, both for the parallel resistance and also (middle) pickup selection. One resistor is connected across the three lugs fed by the middle pickup (yellow wire). If that were the only resistor, and it was also extended to the lug below then in addition to the neck pickup seeing a 250K volume pot, the middle pickup would also be 'on' when the neck pickup was selected. To avoid that they have used a second resistor for the neck pickup alone selection. I guess there are limitations even with a Superswitch! The only way I can see to have separate values for tones would be to use a dual 500K/250K pot like Fender part 0990847000.

Regarding the auto-split, I Initially only noticed the green tap wire, but it is a full 4-wire humbucker as there are actually green and white wires together,. That doesn't change the operation of the auto-split, but it does mean the existing humbucker could be wired for all the usual series/split/parallel options if one were interested in modding the guitar further.

Obviously a lot of thought has gone into the wiring - nothing revolutionary, but a few different ideas neatly brought together.

Dave_Mc

CasperCaster said:

Dave_Mc said:

That's an interesting point about the resistors- I just assumed the resistors were for the single coils. If it is for the tone pot value as well, that's very cool- I honestly don't know, I've managed to avoid needing a superswitch- apart from the one which came stock in my Ibanez- so far!

That's a good call about the tone caps too, as you said, if you put them in series that would probably work as you said.

I've had a bit of a better look at the gut shots now, and looked through all the images. As stated previously, the bottom left pole of the switch is selecting either a single cap (the one bottom right) or both caps in series such that the bridge selection alone sees a lower effective cap value.

The bottom right pole is selection for the middle pickup and also those parallel resistors (so the single coils see 250K from the 500K volume pot). I initially figured that one resistor would be for the tone pot, but that is incorrect - ALL pickup selections actually see the same pot value for the tone control.  The reason there are two resistors is because that bottom right switch pole is doing double duty, both for the parallel resistance and also (middle) pickup selection. One resistor is connected across the three lugs fed by the middle pickup (yellow wire). If that were the only resistor, and it was also extended to the lug below then in addition to the neck pickup seeing a 250K volume pot, the middle pickup would also be 'on' when the neck pickup was selected. To avoid that they have used a second resistor for the neck pickup alone selection. I guess there are limitations even with a Superswitch! The only way I can see to have separate values for tones would be to use a dual 500K/250K pot like Fender part 0990847000.

Regarding the auto-split, I Initially only noticed the green tap wire, but it is a full 4-wire humbucker as there are actually green and white wires together,. That doesn't change the operation of the auto-split, but it does mean the existing humbucker could be wired for all the usual series/split/parallel options if one were interested in modding the guitar further.

Obviously a lot of thought has gone into the wiring - nothing revolutionary, but a few different ideas neatly brought together.

Excellent, that's some serious analysis there, thanks! And I agree- nothing groundbreaking, but nice to see at any price really, and especially nice at the price the Sires are.

MentalSharps

CasperCaster said:

Dave_Mc said:

That's an interesting point about the resistors- I just assumed the resistors were for the single coils. If it is for the tone pot value as well, that's very cool- I honestly don't know, I've managed to avoid needing a superswitch- apart from the one which came stock in my Ibanez- so far!

That's a good call about the tone caps too, as you said, if you put them in series that would probably work as you said.

I've had a bit of a better look at the gut shots now, and looked through all the images. As stated previously, the bottom left pole of the switch is selecting either a single cap (the one bottom right) or both caps in series such that the bridge selection alone sees a lower effective cap value.

The bottom right pole is selection for the middle pickup and also those parallel resistors (so the single coils see 250K from the 500K volume pot). I initially figured that one resistor would be for the tone pot, but that is incorrect - ALL pickup selections actually see the same pot value for the tone control.  The reason there are two resistors is because that bottom right switch pole is doing double duty, both for the parallel resistance and also (middle) pickup selection. One resistor is connected across the three lugs fed by the middle pickup (yellow wire). If that were the only resistor, and it was also extended to the lug below then in addition to the neck pickup seeing a 250K volume pot, the middle pickup would also be 'on' when the neck pickup was selected. To avoid that they have used a second resistor for the neck pickup alone selection. I guess there are limitations even with a Superswitch! The only way I can see to have separate values for tones would be to use a dual 500K/250K pot like Fender part 0990847000.

Regarding the auto-split, I Initially only noticed the green tap wire, but it is a full 4-wire humbucker as there are actually green and white wires together,. That doesn't change the operation of the auto-split, but it does mean the existing humbucker could be wired for all the usual series/split/parallel options if one were interested in modding the guitar further.

Obviously a lot of thought has gone into the wiring - nothing revolutionary, but a few different ideas neatly brought together.

Thanks for the detailed breakdown Casper!

Is the effect of a 500k tone pot on the single-coils minimal,  like some extra high end?

CasperCaster

MentalSharps said:


Thanks for the detailed breakdown Casper!

Is the effect of a 500k tone pot on the single-coils minimal,  like some extra high end?

To clarify, there are still a couple of things I can't see on the circuit, so I have made some assumptions:

- I can't actually see the cap values for the tones, but as 47nF and 22nF are the values people expect to see for single coils and humbuckers respectively, then that is what I assume Sire have aimed for  (achieving 47nF and 23.5nF via series caps, which is close enough). Using two identical caps would make sense because you only need to make a single component available on the line, hence there is no risk of dissimilar caps being transposed when preparing/ soldering the loom.

- Likewise the pots. I can clearly read the makers mark on the back, but I cannot see the actual pot values or tapers. They are probably printed on the wafer and will therefore only be visible when viewed from the top of the pot/ shaft side. Now, the volume pot must be a 500K pot - there would be no point in using the parallel resistors otherwise, and I can't believe it's anything other than an audio taper, given that the rest of the circuit is well thought out/ implemented. It also makes sense to use an identical 500K audio taper pot for tone as well, so that's what I expect they have used.

So, assuming the tone pot is a 500K audio taper then the effect on tone for the single coils would actually be minimal, and only really audible with the pot at '10'. Given that the cap values are correct then the corner frequencies of the filters (for singles and humbuckers) are in the expected places (lower for the singles, higher for the humbuckers). With the tone at '10' the singles will sound a touch brighter than you might expect compared with a 250K pot. But given the steep fall in resistance with an audio taper pot, it will sound much the same as a 250K pot from about '9'.

Dave_Mc

^ @CasperCaster Thanks again for that detailed analysis. I agree (at least with the bits I understand!). It might well have a linear volume, though- plenty of guitars seem to use linear pots for the volumes. (That's not to say it won't use audio, of course.)