Telecaster 4-way switch x2

[onederboy]

so, I got some p-90's in my strat and I was wondering if it would be possible to wire up a 4-way tele switch for the Bridge & Neck pickups and then a second 4-way to control the Middle pickup and combinations with the first switch, is this possible?

[sumgai]

odb,

Yes, it's possible. What did you have in mind for which combos would appear at which switch positions?




sumgai

[onederboy]

on the 1st switch:

1. Bridge
2. Bridge + Neck
3. Neck
4. Bridge * Neck


2nd switch:

1. whatever is selected on switch 1
2. Middle + Switch 1
3. Middle alone
4. Middle * Switch 1


I hope that's clear enough, I tried to make it work once, but all I got was confusion once wired up. I appreciate all the help.

[ashcatlt]

I think it's a darn fine idea. My inclination would be to try to put both switches side by side in the same slot.

The only question remaining: what do you want out of the knobs? Will you be content with Master Volume, Master Tone?

[onederboy]

I had actually tried G&L's PTB system and the treble cut really underwhelmed me, I'd like to include that but if not I'm completely cool with Master Volume/Tone.

[sumgai]

1dirboy,

I had actually tried G&L's PTB system and the treble cut really underwhelmed me, I'd like to include that but if not I'm completely cool with Master Volume/Tone.

Did I miss something in the translation? You just said that you were "less than impressed" with the treble cut on a G&L, yet you "would take it, if it's possible".

Hmmmmm, methinks babelfish.altavista.com is not working correctly............

Moreover, you also said that if you couldn't have that, then you'd settle for a standard tone control setup. Uh oh...........

A standard tone control, as found on all stock guitars since time immemorial, is properly described as a "treble cut" system. Since you did say you'd be cool with that, and since G&L does the same thing on their guitars, I've about scratched a bald spot on my head, as I ponder which way you want to go..........

BTW, your proposed switching arrangement looks good to me!



sumgai

[D2o]

Jul 5, 2008 15:49:41 GMT -5 sumgai said:

I've about scratched a bald spot on my head, as I ponder which way you want to go..........

Since your profile says you are female ... I wouldn't suggest you go scratching any bald spots, ma'am. ;D

[onederboy]

I meant to say that I wasn't impressed with the bass cut on this guitar once I wired it up, I've found it to be very useful on actual G&L's that I've played with the PTB.

Once I'd wired it up on my strat, I'd turn the knob from 10 to 9 and suddenly I had no bass at all. It made my guitar sound like it was coming through an AM radio. So, I guess I could have thought of a better word than underwhelmed. My bad.

[sumgai]

wonderboy,

No, your use of the word was correct, it's just that you applied it to the wrong end of the frequency spectrum, tha's all - no harm, no foul.

OK, now that we've sorted that out..........

A bass cut control can be done, but doing so seems to be not-quite-as-easy as for a treble cut control. The reason, as far as I can tell, is that for any given pickup, and all it's attendant properties, the values of the capacitor and the pot itself can vary by a pretty large amount. Not to mention, just how much cut does one desire, etc........ you get the picture, I'm sure.

Here's a "starter" circuit for a bass cut control. Vary the values as you see fit.



Did you want a schematic for your switching arrangement, or were you just looking for confirmation that your proposal would/would not be a good idea?

HTH





sumgai

[ashcatlt]

He did say he tried it once and got nothing but confused.

I'd say rip the switching part out of this:

Sumgai turned us on to this as a better alternative to the more standard version, which leaves one of the pickups hanging from hot.

You'll be doing this twice. On one of the switches you'll substitute "middle" where it says "neck", and the other switch where it says "bridge".

[sumgai]

ash,

He did say he tried it once and got nothing but confused.

Ah yes, you've pointed out the foible of my most recent post.

1ey, when you turned down that control from 10 to 9, and got a huge amount of cut, that indicates that the taper of the pot (the control) was too steep in the wrong direction. I should have also noted that in addition to experimenting with cap and pot values, you can experiment with the pot's taper. (If this doesn't make any sense to you, read this page on Pot Tapers.)

In further research, I failed to find what taper G&L is using in their PTB circuits. Anyone have better information on this?

HTH




sumgai

[ChrisK]

I'd turn the knob from 10 to 9 and suddenly I had no bass at all.

Taper is.

If a standard audio taper pot is used, turning the bass cut down to 9 on a 500K pot does have a significant resistance change. Since one is in essence using the pot backwards compared to a high cut circuit, at a minimum, a linear taper pot should be used.

In the G&L scheme, the bass cut pot is a linear one (denoted by the "C").

Note that the black dot by each pot indicates the clockwise terminal.

The best pot to use might be a left-handed taper (or reverse taper) audio pot. These are rare.

Try using the correct section on a PAN, not blend Pot since it is essentially a right-handed and left-handed element sharing a common shaft.

You'll be doing this twice. On one of the switches you'll substitute "middle" where it says "neck", and the other switch where it says "bridge".

Yes, but I would like to clarify this;



Note that this does not do the combinations in the order that you stipulated. While the rearrangement of the wiring is a simple thing for any grouping, I would suggest that you keep both switches similar in combinations.

What I cut and pasted gives:

S2
1. Middle
2. Middle + S1
3. Middle * S1
4. S1

S1
1. Neck
2. Neck + Bridge
3. Neck * Bridge
4. Bridge

Note that this gives 16 different switch position combinations; 13 of which are meaningful. I might suggest that you rethink your combinations since you essentially have two guitars here.

One is selected by S1 and S2 when S2 is not in the "middle only" position and the other is when S2 is in the "middle only" position. This would indicate that the "middle only" position should actually select the pickup that you like and use the most.

This wiring is fairly similar to Atchley's "Double Barrel Switching".

[sumgai]

Chris,

Obviously I was looking at something else that day, when I scoped out that particular drawing. Sorta slapped me in the face, if'n you know what I mean.

I was thinking that a reverse taper pot (not really all that hard to find, once you start looking beyond Radio Schlock) would be the more desirable taper here, since we're working from the starting point of the top end of the rotation being the "default" position, not the bottom end (as in most "hi-fi" designs).

But even if they were difficult to find, howzabout we sorta cheat, and modify the taper of a Linear pot with an external resistor, as shown on R.G. Keen's page, linked above? That might work passably well, dontcha think?




sumgai

[ChrisK]

modify the taper of a Linear pot

Sure, however, we need to modify the taper of a rheostat (a two terminal network).

While this can be done, it cannot be done for the taper that we desire. It will let the resistance get bigger faster than linearly (for the reduced span of the parallel combination), but not slower than linearly.

And, with the input impedance of the amp being 500K on a good day, we need at least a 1 M Ohm pot to effect a 1/3 (-10 dB) resistive divider around the series cap (the bass cut final level).

If the amp has a high input impedance (1M), the bass cut circuit has a lesser effect (-6 dB).


With this circuit, one really needs a premium low capacitance cable.