Why two stages in the 5-way Switches?

[Carlos Sanz]

(EDIT: moved by sumgai to General Wiring, 10/22/17)

This is a rather guitar-history question. Probably this has been asked before but I’ve tried to look for an answer unsuccessfully.


My question regards the two-stage classical Fender 5-way switch. I understand how it works but seems to me very complicated.

This is the classical design, with one stage for pick-up switching and another stage for Tone Controls switching:







But as I see it, the same performance could be achieved if we join the pickups with their respective tone controls, using only one stage. Like this (you can see it attached too):
i1262.photobucket.com/albums/ii606/elgurriato/Two%20capacitors_zpsl2qw9jzn.jpg?t=1508590058




Two capacitors are needed then. But was Fender trying to save one capacitor at the expense of creating a more expensive switch? Am I wrong with the second design? The only drawback of this alternative design is the presence of a second capacitor and the fact that the position with the neck and the middle pickups together would have the two capacitors working at the same time, making them more aggressive in the filtering.

Any idea or historic reference? I guess they had the Telecaster switch design and simply adapted it.


Thanks.

Attachments:

[reTrEaD]

Oct 22, 2017 7:52:15 GMT -5 Carlos Sanz said:

I guess they had the Telecaster switch design and simply adapted it.

The switch on the earliest Stratocasters was the same switch used on the Telecaster and the single pickup Esquire before that . . . a three-position switch.

Oct 22, 2017 7:52:15 GMT -5 Carlos Sanz said:

But was Fender trying to save one capacitor at the expense of creating a more expensive switch?

Leo didn't design the three-position lever action switch. It was already being used somewhere else. Perhaps in telephone switching, laboratory equipment, two-way radios, or something else. Perhaps someone more familiar with the history might shed some light here.

He was saving a capacitor, but the switch was a stock item. The switch did become slightly more expensive when he was able to get the supplier to change the detent mechanism to 5-positions (the rest of the switch remained original). It was already a "make-before-break" design so the in-between positions made use of the bridging between lugs that was inherent.

The alternate wiring you proposed is functional. A slight difference in performance should be noted when both pots are at minimum and the selector is in the #4 position (Neck + Middle). The result is two capacitors instead of one, in parallel with the Neck and Middle pickups.

[sumgai]

Carlos,

Sorry, but I had to move this thread, as your question doesn't concern tone control mechanisms so much as it relates more to why Leo made certain design decisions.

To answer your main question, it wasn't a matter of complication. Leo was an Army veteran of WWII, so he knew this switch intimately - it was used throughout the armed services for many purposes, and after the war, it was available on the surplus market for cheap - like, really cheap.  The cost of a capacitor didn't play into the equation at all, they were also cheap.

But more to the point, you need only look at the first axe to use this switch, the venerable Telecaster (nee Broadcaster).  Therein, there were only two pickups, yet a three-way switch was used.  Importantly, the two pups were never chosen in combination, it was one or the other, and that was it, baby.  So why the switch?  Referring to the original schematic, we see that an additional capacitor was inserted in the signal path to further muffle the tone of the Neck pickup in an attempt to sound more 'jazzy', like big-box acoustic-electric guitars of the day. (Think Gibson Super 400 and the like.)*

EDIT: It came to me a few moments after first posting this reply: Leo also used this switch on the Esquire, with even more tone mufflilng via capacitors.  Why?  Well, the whole reason wasn't just the fact that the switch was so readily available on the surplus market, but more to the fact that Leo had seen it stand up to abuse of the highest order whilst in the field - ham-fisted equipment operators didn't have to be delicate with this thing, it was a brute in terms of surviving whatever was thrown at it.  Right there, Leo knew that most guitarists weren't gonna be able to break this thing, and that's always a strong factor in selecting components for a design.

Thus, the decision was not directly related to cost, but to that Mighty Mojo Tone, although cost did play a minor (and happy) part in the final effort.

Transfer all that thinking to the Stratocaster, sans the muffling cap, and you can see what was going on in Leo's mind, back in 1954.

HTH

sumgai

* This was not Leo's best idea - Jimmy Bryant picked up a Telecaster and promptly proceeded to set the world on fire, both alone and with Speedy West, in both Country and Jazz idioms.  He can be said to have started the twang revolution in Country music, years before Rex Carson became Leo's advisor on what country pickers want in the way of tone.

[Yogi B]

It might be worth noting that 4 terminal switches have shown up (and proceeded to cause confusion) for example over at TGP: Alright... WHAT the Heck is This? Vintage CRL 5-Way with 4 NOT 8 Lugs??.

Unfortunately the images from that thread have gone, but searching for the mentioned part/serial number ("PA02220683") turns up this ebay listing: 1975 CRL 2503885 Original 4-Lugs 5-Way Selector Switch for Peavey Guitars

It's interesting that the title specifically mentions Peavey, in the description the seller goes further to specify the "Peavey Foalcon" or uhm Falcon which might not make chronological sense, but does at least make sense in terms of wiring: Falcons only have a master tone control, thus definitely only require half a regular switch.

As the others have pointed out, it's not really about using the simplest switch possible, but what was readily/cheaply available. The fact that Fender used what he did should be proof in itself that your assumption about it being "a more expensive switch" is false.

I bet were still in same situation today: imagine somebody like yourself notices the potential inefficiency of the standard Fender switch and gets serious enough to approach various switch manufacturers from both the US and China. Then, likely, they'd be the recipient of more costly quotes for the simpler (yet otherwise equivalent) switch. At least up to a point, at an excessively large numbers of units you might 'break even', and beyond that point be in profit over the regular switch, but there's not much point -- I don't see a massive demand for a switch with less potential functionality, especially not 'round here!

---

EDIT: Half the switch terminals, half the capacitors... and now with half the forgetfulness!

---

Finally if you didn't mind some funky behaviour in the neck only and middle only positions, when using only half of the switch, you can still have both tones in parallel with the single capacitor as per usual. Here's an example of this wiring in the wild, in someone's rewiring job:


Even when already using two caps (e.g. if you want a different value cap on each tone control) there is still a small advantage to using both sides of switch -- with the tone controls and the pickups going to separate terminals of the switch -- it is simply easier to (dis)assemble in a modular fashion. i.e. you can desolder and replace a faulty pickup without touching the wiring for the tones, or vice-versa.

[reTrEaD]

Oct 22, 2017 13:35:16 GMT -5 Yogi B said:

Finally I'm not sure why, when using half the switch, "two capacitors are needed"

When using a single capacitor and two tone pots without a switch isolating the two, unintended consequences can arise.

Yogi, what happens when the Neck is selected and both tone pots are at minimum?

[Yogi B]

Oct 22, 2017 14:12:49 GMT -5 reTrEaD said:

Yogi, what happens when the Neck is selected and both tone pots are at minimum?

Unintended consequences, that's what. Specifically as you reduce both tone pots, the middle pickup starts to 'bleed' through to the output also. And proof that (A) I should probably get some sleep and (B) sometimes my title should read Profoundly Idiotic Circuit Designer! Although to be fair it is quite a while since I've had a Strat (or anything similar) wired with two tones.

Oct 22, 2017 13:35:16 GMT -5 Yogi B said:

both tones in parallel with the single resistor as per usual

-- wasn't that enough of a clue???

[reTrEaD]

Not a big deal. You had a Myopic Moment. You'll be hard-pressed to find someone who never had one. That's why we discuss.

They say one Awshit wipes away ten Attaboys. If true, you still have an amazingly high total.

[sumgai]

Oct 22, 2017 15:21:04 GMT -5 Yogi B said:

.... Profoundly Idiotic Circuit Designer

You don't really want me to take you up on that, do you?

sumgai

[reTrEaD]

Well he did say "sometimes".

[Carlos Sanz]

Thank you all, guys.



I was afraid I was suffering a Myopic Moment myself because I didn’t understand what was going on in Leo’s Mind. I was thinking about “my one-stage only design” in order to use the other stage for other purposes but I couldn’t understand why they used that way and I thought I was doing something wrong.


I was wrongly assuming that the three-way lever switch was a Leo’s invention.

Thank you for all the info (Specially, I had never heard of Jimmy Briant).


I’ll go on with my designs.

THANK YOU ALL.

[Yogi B]

Oct 23, 2017 12:09:15 GMT -5 sumgai said:

You don't really want me to take you up on that, do you?

To be honest, I initially expected it to be The Guinea Pig. I'd say Profoundly Helpful was a bit of an overstatement.

---

Carlos Sanz
Speaking of the invention of the switch, Electroswitch's Unofficial History of the CRL 1452 might be of interest.

[sumgai]

Yogi,

So be it. You're welcome.

sumgai