Of pots and caps

mnbaseball91

mnbaseball91

New member
I'm working on getting my Warmoth all wired up. It's playable right now, but not all the knobs are satisfactory. Just a couple questions...

1) The tone knobs right now are more or less on/off switches - there's no inbetween or graduation. Is that the fault of the pot itself or the cap? I'd be inclined to think that it's the pot, but the same pots work just fine as volume knobs. Should I experiment with better quality caps?

2) What affect, if any, do the caps have on tone when they're all the way open?

3) I'm using a five way switch with an HSH configuration, meaning that the red and white wires from each of the humbuckers need to be soldered to the switch. This is the schematic I'm using for the switch:
http://www.seymourduncan.com/support/schematics/hum_sing_hum_vol_tone_spl.html
I'm also attempting to do this mod for the bridge pickup:
http://www.seymourduncan.com/support/sum96tip.shtml
I've done it on my Schecter with great success, but I can't figure out a way to have the red and white wires soldered to both the switch and the pot. I tried running a wire from the tab on the switch to the pot, but that made the pot act as a volume knob. What do I do?
 
Re: Of pots and caps

1. You might have your pots wired incorrectly or they are the wrong value pots. Use 500K for humbuckers and 250K for single coils.

2. Some signal will bleed through the pot even when it's on "10". So if you are using a .02 cap vs a .047 or .05 cap, you'll bleed off a little more mids even with the pot on "10" with the .047 cap. You may or may not be able to hear the diff.

Good luck! Lew
 
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Re: Of pots and caps

Thanks for the reply. I do indeed have the knobs wired "backwards", but I didn't think that would effect the roll-off. I'm using 500k with buckers of course.

Anybody have any other ideas?
 
Re: Of pots and caps

mnbaseball91 said:
Thanks for the reply. I do indeed have the knobs wired "backwards", but I didn't think that would effect the roll-off. I'm using 500k with buckers of course.

Anybody have any other ideas?
Click to expand...

I had the same problem with one of my guitars. I would bet that you have linear pots installed instead of audio pots. With the linear, my tone sweep was basically either on or off. The audio pots made the sweep much smoother and much more useable. (In re-reading your origional post I realized that you had 2 questions. This should solve the first problem only.)
 
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Re: Of pots and caps

Now that you mention it, that sounds like a VERY likely scenario...especially because I'm using concentric pots. :smack: I guess I'll just have to live with it.
 
Re: Of pots and caps

heavydutysg135 said:
I had the same problem with one of my guitars. I would bet that you have linear pots installed instead of audio pots. With the linear, my tone sweep was basically either on or off. The audio pots made the sweep much smoother and much more useable. (In re-reading your origional post I realized that you had 2 questions. This should solve the first problem only.)
Click to expand...

I think you may have that the wrong way round. It's been my experience that audio taper pots work better as volume controls while tone controls offer a better sweep with a linear track.
 
Re: Of pots and caps

mnbaseball91 said:
Thanks for the reply. I do indeed have the knobs wired "backwards", but I didn't think that would effect the roll-off. I'm using 500k with buckers of course.
Click to expand...

That will have a dramatic affect on the roll-off, if you have audio-tapers. It means you have the taper going the wrong way, making the problem worse.
Why do you have them backwards?

mnbaseball91 said:
3) I'm using a five way switch with an HSH configuration, meaning that the red and white wires from each of the humbuckers need to be soldered to the switch. This is the schematic I'm using for the switch:
http://www.seymourduncan.com/support/schematics/hum_sing_hum_vol_tone_spl.html
I'm also attempting to do this mod for the bridge pickup:
http://www.seymourduncan.com/support/sum96tip.shtml
I've done it on my Schecter with great success, but I can't figure out a way to have the red and white wires soldered to both the switch and the pot. I tried running a wire from the tab on the switch to the pot, but that made the pot act as a volume knob. What do I do?
Click to expand...

You need to do either of two things:

1. On the first schematic, take the "ground" connection, thats between the two red/white wires on the 5-way, and run that to the "split" pot where the red/white wires go. That will automatically connect the spin-a-split pot to the pup thats selected. (Thats what I'd do.)
Edit: Just to clarify - if you run the "ground" to the spin-a-split pot, don't connect it to ground also. It goes only to the split pot.

2. Run the red/white wire of the bridge pup to the spin-a-split pot as normal. Then take the splin-a-split pot ground back to the 5-way where the bridge red/white would have been.

In other words, in neither case do you run the red/white wires to both the pot and switch. Its either/or.

I can draw a diagram tomorrow. Tonight . . . I'm whooped. ;)

Artie
 
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Re: Of pots and caps

Why do they have them backwards? I was using a top-down view schematic and wiring from the back. It was bad enought he first time I did it... :smack:

And thanks, that makes sense about the spinasplit. All of my electronics experience comes from trial and error guitar wiring so I sometimes have to be told obvious things before they make sense to me. A diagram shouldn't be necessary.

I guess I'll have to heat up the ol' soldering iron tonight!
 
Re: Of pots and caps

mnbaseball91 said:
3) I'm using a five way switch with an HSH configuration, meaning that the red and white wires from each of the humbuckers need to be soldered to the switch. This is the schematic I'm using for the switch:
http://www.seymourduncan.com/support/schematics/hum_sing_hum_vol_tone_spl.html
I'm also attempting to do this mod for the bridge pickup:
http://www.seymourduncan.com/support/sum96tip.shtml
I've done it on my Schecter with great success, but I can't figure out a way to have the red and white wires soldered to both the switch and the pot. I tried running a wire from the tab on the switch to the pot, but that made the pot act as a volume knob. What do I do?
Click to expand...

Why would you want to have both the dial-in coil split and the auto split from the switch?

The reason the pot is acting as a volume control is because that is what it is; when you create a dial-in coil tap you are, in effect, adding a potential divider type volume control to one coil in a series pair. If your guitar is wired exactly as in the colour diagram I see no reason why this should be happening though, as the switching of the coil-tap is occurring entirely on the earth side. The effect you describe would occur if you were splitting the coil to signal rather than earth.

The following should work:
variant12gk.png

variant26tf.png


In the second schematic, the dial-in tap works on both pickups, in the first, only on one.


I would suggest not ditching the capacitor, but enlarging it to maybe 0.47µF.
coiltap9fu.jpg

This effectively keeps the lower frequencies, including the 60hz hum, in the circuit where it remains to cancel the inverted hum in the active coil so you get a split coil which retains noise cancellation properties. I'm not sure of the optimum value for the cap, It's late over here and my brain isn't working, maybe Artietoo has some ideas...
 
Re: Of pots and caps

Octave, that's pretty much the mistake I made. As far as the caps, I'm not following the diagram exactly - I have two concentric pots: a master volume, two tones, and the spin a split. As far as why I'm doing this AND a five way switch, I really like some of the in between settings I get with it in my Schecter.

Artie: Thanks for the diagram. Now I'll go work for real!
 
Re: Of pots and caps

Octave; I don't think that what you posted is going to work - at least, not as you think. You've still got a regular tone control, but you've moved its connection to the red/white pair instead of the black wire. It will still work as a normal tone control in that configuration, rather than as a spin-a-split.

If he connects it as my diagrams show, it should work fine. In theory. :)

Artie
 
Re: Of pots and caps

mnbaseball91 said:
I'm not following the diagram exactly - I have two concentric pots: a master volume, two tones, and the spin a split.
Click to expand...

Well that's cool then 'cos you don't have to worry about the two concentrics, they aren't involved in the mod. However if there is a technical reason why you have to split the coils red/white to signal, you will have to keep the tap wires isolated and take each one to the corresponding signal wire for each pickup via a separate spin-a-split, or get a concentric spin-a-split.


Best of luck!:beerchug:
 
Re: Of pots and caps

ArtieToo said:
Octave; I don't think that what you posted is going to work - at least, not as you think. You've still got a regular tone control, but you've moved its connection to the red/white pair instead of the black wire. It will still work as a normal tone control in that configuration, rather than as a spin-a-split.

If he connects it as my diagrams show, it should work fine. In theory. :)

Artie
Click to expand...

No it does work Artie, i do it all the time. i have it installed on my Dimarzio demonstrator Strat (except its actually got two Seymours and a Kent Artmstrong in it at the moment!)

There's nothing wrong with your diagram either but if you look at mine you will see that it is effectively a tone control acting on the one coil in the pair only. Without the cap the spin a split is simply a volume control acting on one coil. By adding the capacitor between the end tag and earth you stop the low frequencies shorting to earth so they remain in circuit. higher frequencies still go to earth as if it was a normal shorting connection. Tailor the value of the cap right and you can fix it so that below 50Hz (or 60Hz Stateside) the pickup is still a humbucker but the tonal spectrum above that frequency is still affected as in a normal coil tap.

Look at it like this:

ct7qz.png


With the slider up close to the junction between the two coils the pickup is effectively split, except for frequencies below those determined by the value of the capacitor, which are prevented from reaching earth by the capacitor's high impedance to low frequencies. Because these remain in circuit for both coils it means that the pickup is effectively a humbucker for low frequencies and a single coil for high frequencies.

Can you see how it works now?
 
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Re: Of pots and caps

I got it all wired up...the switch works fine, the volume knob works perfectly...but neither tone knob or the spin-a-split do anything at all. You can turn them all day long, but nothing changes. AHHHHHH!

Artie: On your diagram, is that a top down or a bottom view? I tried the wire on both tabs and neither worked, but it can't hurt to know for sure.
 
Re: Of pots and caps

Why not just wire the red and white wires from both pickups to a middle potentiometer lug and one of the other lugs to ground? This way the spin a split works on either pickup that is selected. Why wire the split wires to the switch?
 
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