Double neck. 3 three way switches. 2 A500K & 2 B500K pots. Need a little help.

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Vmcompetello

New member
Hello, I am an auto technician by trade. I just retired and am making an attempt to build a double neck guitar. The guitar has 2 Epiphone T and 2 Epiphone R pickups. It has 3 three way toggles and 4 potentiometers 2 are A and 2 are B. All are 500K. There are instructions but I'm a little lost. There are 2 capcitors on the B pot center lug and grounded to the pot. Other than that, everything is not wired.

I was told there are 2 ways to wire the toggles and a multitude of was to wire the pots with capacitors and resisters. A tad out of my league. Any and all suggestions will be appreciated. Please, I know I'm lost but be kind with the wise cracks!

Thanks,
Vinnie
 
Re: Double neck. 3 three way switches. 2 A500K & 2 B500K pots. Need a little help.

Re: Double neck. 3 three way switches. 2 A500K & 2 B500K pots. Need a little help.

The "T" pickups stand for "Treble"; you have one Treble (bridge) pickup for one neck and another for the other neck. Same goes for "R" pickups which stand for Rhythm (neck) pickups.

"A" potentiometers means "Audio-Taper", where the rate at which the internal resistance of the potentiometer is logarithmic. This is typically used for volume controls, with the explanation that we perceive volume changes in a logarithmic pattern. Volume controls will work with other tapers, but some people may find the control to respond weird. Audio/Logarithmic potentiometers are just the standard in this case.

"B" potentiometers are "Linear-Taper", meaning the rate of change inside the potentiometer is constant. Graphically, think of a straight line with a 1:1 ratio for the x and y axis. These potentiometers are typically used for tone controls and occasionally gain controls.

The capacitors wired to their respective potentiometers create an RC circuit, specifically a low-pass-filter, meaning the combination of a capacitor and resistor create a cutoff-frequency, and frequencies below the cutoff are unaffected, or "passed through" while frequencies above the cutoff are attenuated. This is why as you turn down the tone control, high frequencies are removed to create a darker sound. The opposite is true for a high-pass-filter: frequencies above the cutoff are unaffected, while frequencies below the cutoff are attenuated. The resistor value is changed as you turn the potentiometer - hence why another name for a potentiometer is a "Variable Resistor". Going back to tapers, a Linear "B" Taper will change this resistor value at a constant rate.

One easy way you can wire the guitar is to have a standard Gibson-style wiring (the Treble pickup having a volume and tone control, the Rhythm pickup having a volume and tone control, and a 3-way switch to select either the bridge pickup/bridge and neck pickups simultaneously in parallel/neck pickup), but the 3 way switch that toggles between the necks will be top neck/both necks simultaneously in parallel/bottom neck. Here's a wiring diagram of just that:

25112d1378879664-x2sglefty2.jpg

If you have any questions as to how any of this stuff works, we'll be more than happy to help! :)
 
Re: Double neck. 3 three way switches. 2 A500K & 2 B500K pots. Need a little help.

Re: Double neck. 3 three way switches. 2 A500K & 2 B500K pots. Need a little help.

Thank you so very much for your time and know how. I cannot say how much it is appreciated. I have a question. The guitar came with 3 three way switches as well as having 3 holes cut in the pick guard. Is it possible that you have a diagram for the 3 switches or is the third switch just a redundancy?

Once again, I thank you,
Vinnie
 
Re: Double neck. 3 three way switches. 2 A500K & 2 B500K pots. Need a little help.

Re: Double neck. 3 three way switches. 2 A500K & 2 B500K pots. Need a little help.

Could the third hole be for the output jack, and they just gave you a spare switch? It's hard to say unless the specific guitar model is mentioned. Or it could be each neck has its own respective pickup selector, while the third switch toggles between the necks. There wouldn't really be much benefit to having three switches over two like in the diagram above, as you won't gain specific pickup combinations that are of much use (like with three switches, you could run the bottom neck's treble pickup in parallel with the top neck's rhythm pickup, but that wont really be of any practical use) assuming the switches are normal Gibson/Epiphone styled selector switches.

And you're very welcome.
 
Re: Double neck. 3 three way switches. 2 A500K & 2 B500K pots. Need a little help.

Re: Double neck. 3 three way switches. 2 A500K & 2 B500K pots. Need a little help.

Hello and thank you once again!

I was under the impression that an Epiphone double neck has 3 switches. Since the pickups are Epiphones and the jack hole is already drilled, I thought it would use all 3 switches. One switch hole is between the necks just about between the bridges. The other one is also between the necks but up close to the necks. The third one is up close to the neck also but is below the lower neck.

I'll wire it the way you say to do it but I'll have to replace that pick guard between the necks. That's why I was asking about the double neck Epiphone wiring.

Listen, you are the only one that even attempted to help me so my appreciation cannot be put into words! If you ever have a car problem and need some advice, I'm your guy!

Thanks so much once again!
Vinnie
 
Re: Double neck. 3 three way switches. 2 A500K & 2 B500K pots. Need a little help.

Re: Double neck. 3 three way switches. 2 A500K & 2 B500K pots. Need a little help.

You will need a switch, vol., and tone for each neck. The outputs from these 2 circuits go to the third switch then the output jack. This way you can switch between pickups on either neck and switch between necks. With all 3 switches in the middle position all 4 pickups will be on.
 
Re: Double neck. 3 three way switches. 2 A500K & 2 B500K pots. Need a little help.

Re: Double neck. 3 three way switches. 2 A500K & 2 B500K pots. Need a little help.

For a three switch wiring, it's simpler to reason through if you break it down to think of it as two separate rigs connected through a switch to the output jack. Wire each side like this -

http://www.seymourduncan.com/support/wiring-diagrams/schematics.php?schematic=2h_1v_1t_3w

Pickups to switch, then volume and tone, then output for each pair. Instead of each one going to an output jack however, you would connect them to their respective sides of an output switch. Then the common center lugs of the switch finally go to the jack. Make sense?

I would also add that if you have two linear and two audio pots, the linears would typically be used for volumes, and audios for tone. Volumes can actually work well with either audio or linear depending on how you want them to respond (Gibson and almost all imports use linear volumes, while Fender, PRS, and many others use audio). Tone pots on the other hand pretty much have to be audio if you want them to deliver any usable range. Linear pots will do almost nothing in the tone position until you get down to the bottom third, where it acts more like an abrupt on/off tone switch.

Good luck!
 
Re: Double neck. 3 three way switches. 2 A500K & 2 B500K pots. Need a little help.

Re: Double neck. 3 three way switches. 2 A500K & 2 B500K pots. Need a little help.

Thanks to all once again. I'm a little confused because someone says use the "A" pots for volume and the other says use the "A" pots for tone. I am not Einstein with electronices but I know the A pot is logarithmic and the B pot is linear. Aside from that, I don't know which one is better for volume or tone.

I have time because I'm using nitro cellulose paint and that takes a bit of time to finish especially when you have plenty of time on your hands as I do. Could someone clear up the "pot" issues for me. I think everything else is clear.

Thanks to all who answered. I know what it's like to explain things when the person your explaining it to is a novice!

Vinnie
 
Re: Double neck. 3 three way switches. 2 A500K & 2 B500K pots. Need a little help.

Re: Double neck. 3 three way switches. 2 A500K & 2 B500K pots. Need a little help.

Here's a video series I made a while ago -

http://www.youtube.com/playlist?list=PLO33g8sM_b8V2Z25rI2VPWFOb00X79wIn

Videos 2 & 3 touch on tapers in the respective positions.

Either audio or linear will work for volume - audio if you want the quick clean up from overdrive, linear for smoother volume adjustment playing clean, or for more effective range of adjustment in the typical middle position (which won't really apply so much to your wiring setup).

For tone pots, linear doesn't work well until you get in to the really low ranges, typically in the 50-100k range of pot values. With a 250k-500k pot they will pretty much act as tone on/off switch at the very bottom, so tone pots are almost exclusively in the domain of audio tapers.

Personally, I'd be inclined to use audio taper pots all around for a rig like that, modifying the volume tapers a bit with use of a treble bleed mod. That's a personal preference though. The majority of guitars sold today use linear volumes and audio tones, although a good many still use audio all around (almost none use linear for tone controls).
 
Re: Double neck. 3 three way switches. 2 A500K & 2 B500K pots. Need a little help.

Re: Double neck. 3 three way switches. 2 A500K & 2 B500K pots. Need a little help.

Hello once again,

First, thanks for all the help and replies. Everyone is very helpful. I wish I knew what a treble bleed mod was but I don't. I have another issue. I wired it like "My account's" diagram. I check it a few times but I get a hum like there is a bad ground somewhere but the grounds are all connected. Any ideas besides stick to fixing cars?

It is a lot of fun playing with this and I'm hoping to learn more of the jargon so I can participate more. Right now I just have this hum problem. It seems to get better when I'm touching the strings but doesn't go away completely. All the pots are grounded as are the switches and the bridges. The pickups only grounded when they are selected as per the diagram.

I have a 1987 Les Paul Custom that I don't even know when it's plugged in. I'm not comparing this guitar to a Les Paul but, I feel there is too much noise.

Thanks in advance,
Vinnie
 
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