Sanity Check, Please

[BrotherJack]

Backstory first:  I have never liked knobs on my guitars.  The only thing they're good for is turning to 10, or cursing at when I accidentally turn them down from 10.  If I want to jack with the volume, my volume pedal is much easier to run with precision than trying to put a pinky on a volume knob while picking simultaneously, and tones are what my effects and amp make,  not something I need a knob to adjust with (though I like the 'mellowing effect' that simply having a tone pot in the circuit creates).  Anyway here's what I'm planning to do, if you guys could sanity check my wiring:

First part is standard stuffs:  2 Humbuckers hooked up to a Gibson type 3 way (Bridge, Both, Neck) switch.  The other two bits are the part I want sanity check on:


1)  ON / OFF / ON DPDT switch wired with the commons being hooked to ground, which will result in the following scenario:

Position 1: short hot wire on the output jack to ground (ie: turn the guitar off).
Position 2: no effect (ie: humbuckers doing whatever the 3 way switch and switch # 2 below are set to)
Position 3: short the second coil on both pickups to ground (ie: instant single-coil pickups - not as selectable as per-pickup switching, but I'm OK with that)

That sound sane?  Or am I missing something?

Next (and this is the part I'm the most not sure about):

2) A second ON / OFF / ON switch wired with common 1 to hot output of jack and common 2 to ground.  Will jumper the switchable legs on one side with 250khom resistor (not capacitor), and on the other a 500 kohm resistor.

Position 1:  Have hot output connected to ground through a 250kohm (or 500kohm maybe) resistor providing a 'hooked up to a 250k tone pot, but pot on full' effect.
Position 2:  Wide open direct-to-jack pickup connection
Position 3:  Have hot output connected to ground through a 500khm (or 1Mohm maybe) resistor providing a 'hooked up to a 500k tone pot, but pot on full' effect.

I got the idea for this switch pretty much entirely from this diagram:

But I am not finding much documentation on what different resistor values will do, but I am assuming adding a 250k resistor is like adding a 250k pot to the circuit, no?

Anyway, that's my insanity.  Net result should be a guitar with a standard gibson 3-way toggle, and two small switches that handle off/on/coil-split and warm-bright-morewarm choices.  You guys who know something more than me about circuits and guitar wiring, am I missing something/planning something wrong?

Thanks,

 

[line6man]

Firstly, that diagram is overly complicated. Don't use two poles to do the work of one, or you will hear more popping noises when switching. Only one pole is necessary for the pickup selection, and only one pole is necessary for the resistor switching.

The first switch is fine. No issues there.

The second switch, as I explained, should only be wired for one pole of switching. As far as the resistances go, it is doubtful that you are going to be able to hear 1M Ohms, and even 500k Ohms is a bit too subtle for most people. (Unless you have very high impedance pickups.) You have the bypass setting, so there is no need for very subtle settings. Go for bypass, average load, and "dark" load.

Off topic, but if this were my guitar, the darkest setting would be a capacitor rather than a resistor. Just a preference, though.

 

[BrotherJack]

Thanks, that's exactly the kind of feedback I was looking for! 

Questions though:

1) Won't I run into trouble by having both pickups second-coil wires shorted together full-time (which I would on a single pole switch)?

2) What size capacitor for the 'dark' setting?  I have 0.47 and 0.22 on hand i could play with.    The humbuckers are about 8kohm (though I also have some 12kohm blade pickups I may want to try this in a different guitar with) (or would the ohms of the pickup matter?).

Thanks!

 

[BrotherJack]

One more question:  for the resistor, what would you recommend?  100k?  250k?  something else?

Thanks,

 

[line6man]

Thanks, that's exactly the kind of feedback I was looking for! 

Questions though:

1) Won't I run into trouble by having both pickups second-coil wires shorted together full-time (which I would on a single pole switch)?

2) What size capacitor for the 'dark' setting?  I have 0.47 and 0.22 on hand i could play with.    The humbuckers are about 8kohm (though I also have some 12kohm blade pickups I may want to try this in a different guitar with) (or would the ohms of the pickup matter?).

Thanks!

Why would you run into trouble? That's standard procedure for coil splitting.

0.47 and 0.22 are inappropriate in any prefix. In uF, you are an order of magnitude greater than what would be used on a tone control. That would be absolute mud. In nF, you have an extremely small capacitance that probably can't even be heard. Try finding your sweet spot on a standard tone control and making note of the capacitance and resistance. There is no harm in throwing a resistor in series with the capacitor, to avoid experimentation with capacitances. It's easier.

Also, indeed the DC resistance of your pickups is basically meaningless. People like to throw numbers around because you can get a reading off of a $5 multimeter and sound like you have a quantification of something. The reality is that DC resistance is only useful if you are winding the pickup, or trying to authenticate a particular pickup by its specs. The more useful specs are inductance and impedance. Both of which are significantly more challenging to measure or calculate, and hence, pickup manufacturers rarely publish them.

As far as the resistance goes, that depends on personal preference. For a setting that is meant to sound like you have a volume pot in the circuit, I would go for a 220k resistor.

 

[BrotherJack]

Hello,

I probably quoted the numbers wrong - these are standard guitar-use capacitors, whatever uF a '22' and a '47' would be.    Still think I need something else, or would these do?  If I understand it, wiring one of these in would be the == of cranking the tone knob all the way to 0, yes? no?

And the trouble I thought I might run into, would be that in a single pole switch in the case of the first switch, I end up with the wires from both pickups that I am going to short-to-ground to coil split when switch is in appropriate position, they would be touching each other 100% of the time, and when they are touching each other and not grounded, this may (or may not, I dunno) cause problems?

Thanks again, your advice is greatly appreciated!

 

[line6man]

Hello,

I probably quoted the numbers wrong - these are standard guitar-use capacitors, whatever uF a '22' and a '47' would be.    Still think I need something else, or would these do?  If I understand it, wiring one of these in would be the == of cranking the tone knob all the way to 0, yes? no?

And the trouble I thought I might run into, would be that in a single pole switch in the case of the first switch, I end up with the wires from both pickups that I am going to short-to-ground to coil split when switch is in appropriate position, they would be touching each other 100% of the time, and when they are touching each other and not grounded, this may (or may not, I dunno) cause problems?

Thanks again, your advice is greatly appreciated!

0.047uF/47nF and 0.022uF/22nF are the standard values on a tone control. Indeed, a capacitor alone would give the effect of a tone control on "0."

You will be using two poles to do coil splitting for two pickups. Wire both commons to ground. The first throw on the first pole will go to the bridge pickup, and the first throw on the second pole will go to the neck pickup. The second throw on either pole will go to the output jack. The other second throw can just be left open.

 

[BrotherJack]

Hello,

Ah, OK, so I would still use a DPDT on the first switch, like so (forgive poor ascii art), if each 'o' was one pole, and we are looking at the bottom of the DPDT ON / OFF / ON switch:


output hot wire -> o o <- nothing
          ground -> o o <- ground
coil tap wires p1-> o o <- coil tap wires p2


So in position 1, both of the top two poles connect to the ground on the common, but all we care about is that the hot on the output jack gets grounded creating 'off'.
Position 2 (all open) nothing gets grounded so things work as normal
Position 3 both of the bottom two poles connect to the ground on the common, thus coil tap wires get grounded, creating split coil effect

Sound right, or am I missing the point still (always a very real possibility) 

Thanks,

 

[BrotherJack]

OK, I did a quick and dirty little diagram (borrowing a few things from the original I stole the tone-switch idea from).    As we discussed, would prefer to go to a single-pole 3 position switch for the tone knob, but since the DPDT also would work, technically speaking, and I wouldn't have to make changes to diagram, I left it shown here as a DPDT.  So, other than the DP vs SP preference regarding the tone switch, this all look sane?

 

[line6man]

The diagram is correct, aside from the use of two poles to do the job of one, on the bright/dark switch.

There is an error in your terminology. What you are doing is coil splitting, not tapping. Tapping cannot be done with standard humbuckers. But that's a minor technical point.

 

[BrotherJack]

As long as I get the desired functionality, I'm not caring so much about the order.  But I am confused a bit - since I am using the 1st "on" position of the "on/off/on" switch to produce my "off" functionality by grounding the hot output wire (instead of the more normal use of a switch, such as using an off position to break the hot output connection) - won't I indeed get the following:

Pos1: Guitar makes no sound
Pos2/middle: Guitar makes normal sound
Pos3:  Guitar makes sound it makes when 2nd coil is grounded out.

?

Thanks so much for your patience with me and my ignorant questions!

 

[line6man]

As long as I get the desired functionality, I'm not caring so much about the order.  But I am confused a bit - since I am using the 1st "on" position of the "on/off/on" switch to produce my "off" functionality by grounding the hot output wire (instead of the more normal use of a switch, such as using an off position to break the hot output connection) - won't I indeed get the following:

Pos1: Guitar makes no sound
Pos2/middle: Guitar makes normal sound
Pos3:  Guitar makes sound it makes when 2nd coil is grounded out.

?

Thanks so much for your patience with me and my ignorant questions!

Disregard my previous statement regarding order. I edited the post.

The order is indeed off/on/split.

 

[BrotherJack]

Status report (and a question)

Status: wired it all up, soldering the joints I'm sure I am going to leave, just twsiting together the ones I may change yet.  Results?  Everything works exactly as planned!    Off/On/Single Coil is done like dinner, I adore it!  Screw you volume pots, never again! 

Now the dark/wide-open/warm switch .... it works as expected, but not 100% happy with the overall effect on either side. 

The resistor was closest - I did a 100K resistor (per the advice of that earlier diagram), and that was cool.  It wasn't really dramatic, but certainly noticeable, about net result'ed about what I'd expect from a having standard volume/tone/etc pots wired in, which is to say it took a bit of the harsh edge off that comes from a humbucker-direct-to-output-jack wiring.    If I was just going to skip having a tone switch, I'd probably like to simply wire this into the circuit without a switch and call it a day (actually may do that for this particular guitar to avoid having to drill a new hole, and keep this trick for a later build).  But for an 'effect switch', I think I'd want a little more of the effect.

On the other leg, the cap was way-off.  I couldn't dredge up my 47nf in my 'guitar stuff' box, so I tried a 22nf cap instead.  That was WAY too dark (think "amplifier under water" dark). 


So, my question(s) - for the warm leg, I have a wide variety of resistors on-hand to play with.  I presume going lower (ie: from a 100k to a 50k or 1k) resistor will get me more 'warm/dark', right?  Ie: less resistance when connected to ground = more sound bled off to ground?  If so, I can play with that to my hearts content till I find my happiest spot.  If not, I can go higher too.

For the 'dark' leg, tell me about capacitors.  Do I want bigger nf numbers to get to 'less dark', and if so, would you rough guess that a 47 would be about right for a medium-output humbucker, or should I go buy something different rating from the normal 'guitar sizes'?  I think what I'd like is something that would be about like cranking the tone knob from 10(treble) down to maybe 4-ish (not all the way to all-bass, but past mid-point). 

Thanks again for all the assist - it is very very much appreciated!

Cheers!

 

[line6man]

So, my question(s) - for the warm leg, I have a wide variety of resistors on-hand to play with.  I presume going lower (ie: from a 100k to a 50k or 1k) resistor will get me more 'warm/dark', right?  Ie: less resistance when connected to ground = more sound bled off to ground?  If so, I can play with that to my hearts content till I find my happiest spot.  If not, I can go higher too.

Yes. The lower the resistance, the more treble is bled to ground.

For the 'dark' leg, tell me about capacitors.  Do I want bigger nf numbers to get to 'less dark', and if so, would you rough guess that a 47 would be about right for a medium-output humbucker, or should I go buy something different rating from the normal 'guitar sizes'?  I think what I'd like is something that would be about like cranking the tone knob from 10(treble) down to maybe 4-ish (not all the way to all-bass, but past mid-point). 

The higher the capacitance, the lower the frequency cutoff, and vice versa. If 22nF is too dark, try something lower. Perhaps 15nF or even 1nF. Alternatively, put a resistor in series with the capacitor instead of changing its value.

 

[BrotherJack]

For the 'dark' leg, tell me about capacitors.  Do I want bigger nf numbers to get to 'less dark', and if so, would you rough guess that a 47 would be about right for a medium-output humbucker, or should I go buy something different rating from the normal 'guitar sizes'?  I think what I'd like is something that would be about like cranking the tone knob from 10(treble) down to maybe 4-ish (not all the way to all-bass, but past mid-point). 

The higher the capacitance, the lower the frequency cutoff, and vice versa. If 22nF is too dark, try something lower. Perhaps 15nF or even 1nF. Alternatively, put a resistor in series with the capacitor instead of changing its value.

Ahhhhhhhh (light bulb going off in my dim head).... so if I add resistance, it will bleed less to ground (sounds so obvious and simple when said that way, but I had not thought of it).    Seeing as how I have a pile of resistors of a variety of sizes, and no other capacitors on-hand, that's a heck-of-an-idea for fooling around till I get in the neighborhood I want to be in.   

line6man, you are awesome!  Thank you, thank you, thank you!