Extending my rubbish wiring (again!)

horse

Any help much appreciated:

I've got 2 humbuckers wired up as follows:

https://images.app.goo.gl/ccGyPQGkfYu5B6Ay7

Seems to work as expected other than the tone, which seems to do nothing until its almost turned down, then it rapidly reduces the volume to zero.

I can't see anything visually wrong with the wiring, so is a faulty capacitor most likely?

It's a .22 capacitor with a 500k pot.

Thanks in advance for any help.

SteveRobinson

Is it a linear pot by any chance? You need log for tone.

horse

SteveRobinson said:

Is it a linear pot by any chance? You need log for tone.

 I think it was an a500, so log i think?

SteveRobinson

Ah I've just re-read. Yes if the volume is cut entirely then the capacitor could well be shorted.

ICBM

horse said:

Seems to work as expected other than the tone, which seems to do nothing until its almost turned down, then it rapidly reduces the volume to zero.

I can't see anything visually wrong with the wiring, so is a faulty capacitor most likely?

It's a .22 capacitor with a 500k pot.

Do you mean .022uF? Although even a .22uF won't reduce the volume to zero. It does sound like the cap may be internally shorted (which can happen if they get overheated), but check for physical shorts between the cap leads and the pot casing, or bits of stray solder or wire strands first.

Funkfingers

Need to see photographs of your actual wiring to remotely diagnose anything.

Probably a simple oversight.

I reckon that there is an error in the schematic diagram. The signal arrives at the centre lug of the tone pot. The upper frequencies are bled to ground via the capacitor. The remaining frequencies are bled to ground via the lug soldered to the pot chassis. (Exactly like any volume pot.)

The capacitor might as well not be there. Removing it from circuit will make naff all difference. 

Rewire in one of two ways. 
1) Have the capacitor in circuit between the volume and tone pots.
2) Undo the permanent solder joint between terminal 3 and the chassis. Reconnect the "input" end of the capacitor to terminal 3.

horse

Funkfingers said:

Need to see photographs of your actual wiring to remotely diagnose anything.

Probably a simple oversight.

I reckon that there is an error in the schematic diagram. The signal arrives at the centre lug of the tone pot. The upper frequencies are bled to ground via the capacitor. The remaining frequencies are bled to ground via the lug soldered to the pot chassis. (Exactly like any volume pot.)

The capacitor might as well not be there. Removing it from circuit will make naff all difference. 

Rewire in one of two ways. 
1) Have the capacitor in circuit between the volume and tone pots.
2) Undo the permanent solder joint between terminal 3 and the chassis. Reconnect the "input" end of the capacitor to terminal 3.

 That's interesting - I'll try adjusting the position of the capacitor before ordering any new ones.

Thanks all

SteveRobinson

@Funkfingers is right, the diagram is wrong 

ICBM

I confess to not even looking at it before because it was slow to load and I know how to wire a guitar anyway... it didn't occur to me that a diagram on the Duncan website could be that badly wrong. Anyway, it is, and from the described symptoms, it's probably all that's wrong.

The simplest way to correct it is to connect the cap between the volume pot end terminal and the tone pot middle terminal, in place of the black wire. If the cap isn't long enough, undo the solder joint between the end terminal of the tone pot and the casing, and connect the cap there instead.

Funkfingers

Apologies for banging on about this again but the Seymour Duncan schematic diagrams section has been unreliable since the entire website underwent a major overhaul by a third party graphic design contractor approximately ten years ago.

The diagrams were spruced up appearance-wise but there seemed to be no competent person willing or able proof read them. Thus, you could refer to four or five common circuit diagrams with no problems only to be foxed by the sixth because it has a howler in it.

The SD website Administrators were so pleased to be informed of this that they ran twenty red lights in my hono(u)r. Years later, the errors and omissions have still not been corrected.

In the case of the diagram used by the OP, somebody has included both of the commonest ways of connecting up a tone control.

On a positive note, the slavish following of official published diagrams by home guitar techs creates gainful employment for gents such as Steve Robinson. 

BillDL

I'm glad you mentioned this because I was totally flummoxed by one of the Seymour Duncan wiring diagrams about 6 years ago.  It was a bit more convoluted than basic jobs I can generally do without a diagram, but I just couldn't get it to work properly.  I was working with different coloured pickup wires and I thought I had made a mistake when I drew it out myself with coloured pens, but I eventually got it working by mentally tracing how I felt it should be connected and then swapping wires around.

Funkfingers

The diagrams supplied with brand new SD pickups are fine, if basic. The older line drawing ones are correct but concentrate on the usual suspect circuits. The more recent ones go in for a bit of half-tonal shading. They are also correct but still stick to the obvious circuits.

Anything out of the ordinary and you need to break out pens, a napkin and a big bottle of correction fluid.

Twas ever thus. I originally registered on the Duncan forum to find out more about the old Active EQ series bass guitar pickups - the ones with little DIP switches on the casing. Turned out that I already knew more than the SD customer support employees whose jobs it was to answer customer queries. 

Ever the skeptic, it seemed to me that some SD Inc. staff expected technically-minded forum regulars to field those questions for them. This notion was confirmed when the company enlarged its social media presence. The FB pages explicitly stated that forum users would be happy to answer noob questions. (Nice of them to ask first!) The forum was soon inundated by endless dumb noob questions from a Mrs. Trellis of North Wales.

Luckily, there were some seriously clever pickup geeks on that forum. Plenty of worthwhile wiring ideas and pickup modification suggestions.

It was never quite the same after Seymour relinquished control to his ex-wife and her new husband. 

horse

You guys are legends thank you - moved the capacitor and that sorted it

Dave_Mc

Funkfingers said:

Apologies for banging on about this again but the Seymour Duncan schematic diagrams section has been unreliable since the entire website underwent a major overhaul by a third party graphic design contractor approximately ten years ago.

The diagrams were spruced up appearance-wise but there seemed to be no competent person willing or able proof read them. Thus, you could refer to four or five common circuit diagrams with no problems only to be foxed by the sixth because it has a howler in it.

I've seen you post about it several times- I'd say what happened in this thread alone has vindicated you! At the very least, until they sort it out, it deserves to be pointed out- less experienced people might be tearing their hair out trying to figure out what's wrong.

Funkfingers

Dave_Mc said:

until they sort it out

Don't hold your breath, waiting for that to happen.

I'm afraid that the people in charge at SD Inc. seem to believe that they are infallible. They are more likely to snort it up rather than sort anything out.

horse

Now, if I wanted to make some adjustments..

If I added another volume.pot, could I wire one between the bridge and the switch, and one between the neck and the switch? Eg to give separate control of each?

I think I'd also ideally like the tone to only affect the neck (or at least not bridge only position). Could I position the tone between the neck and switch too? I'm guessing it might not work like that?!

ICBM

horse said:

Now, if I wanted to make some adjustments..

If I added another volume.pot, could I wire one between the bridge and the switch, and one between the neck and the switch? Eg to give separate control of each?

I think I'd also ideally like the tone to only affect the neck (or at least not bridge only position). Could I position the tone between the neck and switch too? I'm guessing it might not work like that?!

Yes, yes and yes. That's how a four-control Gibson is wired if you omit the tone control for the bridge pickup.

horse

ICBM said:

horse said:

Now, if I wanted to make some adjustments..

If I added another volume.pot, could I wire one between the bridge and the switch, and one between the neck and the switch? Eg to give separate control of each?

I think I'd also ideally like the tone to only affect the neck (or at least not bridge only position). Could I position the tone between the neck and switch too? I'm guessing it might not work like that?!

Yes, yes and yes. That's how a four-control Gibson is wired if you omit the tone control for the bridge pickup.

 Great thanks - I'll see if I can get my head around it

ICBM

horse said:

Great thanks - I'll see if I can get my head around it

Very simple - use this diagram if you want the tone control to work only on the neck pickup when the volumes are turned down:




And this one if you want it to work in the middle position regardless of where the volumes are set:



In both cases simply leave out the bridge tone pot and its cap.

In either scheme the tone control will work in the middle position when both volumes are up full.

horse

ICBM said:

horse said:

Great thanks - I'll see if I can get my head around it

Very simple - use this diagram if you want the tone control to work only on the neck pickup when the volumes are turned down:




And this one if you want it to work in the middle position regardless of where the volumes are set:



In both cases simply leave out the bridge tone pot and its cap.

In either scheme the tone control will work in the middle position when both volumes are up full.

 That's really helpful thanks

Funkfingers

The other option is 2 Vol., Master Tone like a Flying Vee or Explorer.

Pickup > individual volume > selector switch > master tone > output socket.