Four Ways to Wire a Tone Pot

jaymenon

Is it true that they are functionally identical?

And if so - then why would you want a tone capacitor trailing across the control cavity connecting one pot to another?

Wouldn't it be far simpler to have it as an integral part of the tone pot 'complex', as in the the top two pictures...? 

Roland

Functionally, in terms of circuit logic, they do the same thing.

Practically, in terms of noise reduction, I prefer to have metal items connected to earth rather than to live. This rules out option 4.

In terms of reliability I wouldn't span the gap between volume and tone with a capacitor, which rules out option 3.

jaymenon

Roland said:

Functionally, in terms of circuit logic, they do the same thing.

Practically, in terms of noise reduction, I prefer to have metal items connected to earth rather than to live. This rules out option 4.

In terms of reliability I wouldn't span the gap between volume and tone with a capacitor, which rules out option 3.

I agree.

It’s interesting that Collings do it this way, and also install a transparent control cavity cover to illustrate their wiring…

ICBM

3 is the lowest noise because the remainder of the pot track is the other side of the ground connection and so can’t put noise onto the signal path.

As long as there’s a little flexibility in the cap leads it won’t be unreliable, and it’s also the easiest and cheapest to wire up in a mass-production environment, since there is no extra wire used. I would guess the second reason is why Gibson did it like this, but the first may have been a consideration.

Funkfingers

Option 3 is what Gibson does in Les Paul and SG models. Collings has simply followed Gibson convention on their Gibson-inspired 290.

This century, I have been mostly using option 2. 

WezV

Option 3 also gives a bit more rigidity to the whole harness when using decent quality caps and a solid ground wire round the pots. 

This can be useful when wiring it away from the guitar, especially if you are doing them in bulk

Sporky

They're all wrong, because they all involve soldering to the back of a pot. 

Danny1969

The pic doesn't show the load connected. Technically there is a difference with no 3 .... the others can kinda be viewed as RC low pass filters with the normal resistor (variable in this case ) in series and the capacitor after in parallel with the load .... no 3 has the cap in series and then a resistor (variable) to ground in parallel with the load. This will change the time constant of the cap. 

I know where the load is going to connect but just saying 

BillDL

jaymenon said:

It’s interesting that Collings do it this way, and also install a transparent control cavity cover to illustrate their wiring…

It's suppose the transparent cover is there for two possible reasons:

(a) So the owner can check the capacitors for deterioration and spot any loose wires if there is a fault, and be able to do so without removing the cover, and possibly also to allow a potential buyer to see the wiring and the serial number without removing the cover.

(b) Showing off their wonderfully neat and well executed work, including the brand-name capacitors that no doubt add massive amounts of tone.

I would lean towards the (b), but I would be more impressed if they had made it a bit neater.  The sides of the routing are left as bare wood and there appear to be splinters of wood down at the bottom of the rout that can end up inside pots if they are disturbed and come loose.  Maybe the bare wood is so that people can see that it's not laminate or pancaked layers.  Who knows, but I think it's just pretentious.

thecolourbox

Four Ways to Wire a Tone Pot

Paul Simon's first draft demo title for 50 Ways to Leave Your Lover?

ICBM

BillDL said:

(b) Showing off their wonderfully neat and well executed work, including the brand-name capacitors that no doubt add massive amounts of tone.

I would lean towards the (b), but I would be more impressed if they had made it a bit neater.  The sides of the routing are left as bare wood and there appear to be splinters of wood down at the bottom of the rout that can end up inside pots if they are disturbed and come loose.  Maybe the bare wood is so that people can see that it's not laminate or pancaked layers.  Who knows, but I think it's just pretentious.

It looks really crap - the sort of thing you'd see on a trade show special to show off the posh caps they're fitting, but not what I would want on a guitar that's actually going to be used.

WezV

ICBM said:

BillDL said:

(b) Showing off their wonderfully neat and well executed work, including the brand-name capacitors that no doubt add massive amounts of tone.

I would lean towards the (b), but I would be more impressed if they had made it a bit neater.  The sides of the routing are left as bare wood and there appear to be splinters of wood down at the bottom of the rout that can end up inside pots if they are disturbed and come loose.  Maybe the bare wood is so that people can see that it's not laminate or pancaked layers.  Who knows, but I think it's just pretentious.

It looks really crap - the sort of thing you'd see on a trade show special to show off the posh caps they're fitting, but not what I would want on a guitar that's actually going to be used.

I find the screw position choice rather odd considering how close they made it to the gibson classic

BillDL

I've just realised you are selling a Collings "LP" style guitar @jaymenon. I hope you aren't insulted if it was a photo of your own guitar I was being critical of there, but I was just being honest with my thoughts.

jaymenon

Oh no Bill - that’s not a photograph of my guitar

WezV

They make bloody great guitars even with  the very minor criticism of clear plates and different screw positioning 

Dave_Mc

ICBM said:

3 is the lowest noise because the remainder of the pot track is the other side of the ground connection and so can’t put noise onto the signal path.

As long as there’s a little flexibility in the cap leads it won’t be unreliable, and it’s also the easiest and cheapest to wire up in a mass-production environment, since there is no extra wire used. I would guess the second reason is why Gibson did it like this, but the first may have been a consideration.

If it's lower noise, wouldn't that mean it's "better", everything else being equal?

Can you do the volume treble pass/bleed trick with that layout, though? The one with the cap from the middle lug of the volume to the unused lug on the tone pot? I like to use that type of treble bleed usually...

BillDL said:

jaymenon said:

It’s interesting that Collings do it this way, and also install a transparent control cavity cover to illustrate their wiring…

It's suppose the transparent cover is there for two possible reasons:

(a) So the owner can check the capacitors for deterioration and spot any loose wires if there is a fault, and be able to do so without removing the cover, and possibly also to allow a potential buyer to see the wiring and the serial number without removing the cover.

(b) Showing off their wonderfully neat and well executed work, including the brand-name capacitors that no doubt add massive amounts of tone.

I would lean towards the (b), but I would be more impressed if they had made it a bit neater.  The sides of the routing are left as bare wood and there appear to be splinters of wood down at the bottom of the rout that can end up inside pots if they are disturbed and come loose.  Maybe the bare wood is so that people can see that it's not laminate or pancaked layers.  Who knows, but I think it's just pretentious.

There's a bigger problem with it. I suspect I'd be too scared to attack an expensive Collings with a soldering iron, but if I did, it would let other people see the standard of my soldering work...

ICBM

Dave_Mc said:

Can you do the volume treble pass/bleed trick with that layout, though? The one with the cap from the middle lug of the volume to the unused lug on the tone pot?

No, you can’t use that circuit with the middle terminal grounded.

Dave_Mc

ICBM said:

Dave_Mc said:

Can you do the volume treble pass/bleed trick with that layout, though? The one with the cap from the middle lug of the volume to the unused lug on the tone pot?

No, you can’t use that circuit with the middle terminal grounded.

Thanks, I was worried that was the case, I remember you told me before that you had to use a very specific tone pot wiring to make that type of treble pass work.

ICBM

Dave_Mc said:

I remember you told me before that you had to use a very specific tone pot wiring to make that type of treble pass work.

Yes - the middle terminal of the tone pot must be connected to the input of the volume - diagram 2 above.

Dave_Mc

ICBM said:

Dave_Mc said:

I remember you told me before that you had to use a very specific tone pot wiring to make that type of treble pass work.

Yes - the middle terminal of the tone pot must be connected to the input of the volume - diagram 2 above.

Yeah that's what I thought and that's the way I've been doing it. Thanks

jaymenon

ICBM said:

Dave_Mc said:

I remember you told me before that you had to use a very specific tone pot wiring to make that type of treble pass work.

Yes - the middle terminal of the tone pot must be connected to the input of the volume - diagram 2 above.

I'm a bit confused:

It is certainly the input of the volume control that needs to connect to one of the terminals of the tone pot, but it doesn't matter how the tone pot is wired does it? 
i.e. the treble pass capacitor/resistor should work with diagram 1 as well right?