Need help understanding CRL 3-way switch

Discussion in 'Luthier's Guitar & Bass Technical Discussion' started by guit_lar, Feb 4, 2012.

  1. guit_lar

    guit_lar Member

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    I'm trying to understand how a new CRL 3-way switch works, what is connected to what when the switch is in the 3 different positions.
    I found some diagrams that show the lugs labeled A0, A1, A2, A3, B0, B1, B2, B3, and in colors red and blue, in addition to some uncolored.
    I don't know how to interpret these diagrams.
    I want to know how the switch works electrically. I don't need a specific wiring diagram (yet anyway).
    If anybody can help me with this, or point me to a resource (with a full, simple explanation), I'd really appreciate it.
    Thanks.
     
  2. GM Reszel

    GM Reszel Member

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    [​IMG]

    It is essentially a DP3T (Double pole, Triple throw).

    So, 2 poles, 3 positions. It might be helpful to think of it as 2 separate switches mounted on the wafer (actually two SP3T's--single pole triple throw).

    Each side of the switch is independent of the other. You can discern what the switch does mechanically by looking at one side, advancing the lever and notice what the switch contacts do.

    Look closely and note each side has 4 lugs. One lug is always in contact with the 'blade' which has a raised 'hatchet' that comes into contact with the other 3 lugs as you advance the switch. This function is repeated on the other side of the switch.

    I encourage you to hold the switch and watch what the contacts do as I've described above and I think you'll understand it like a light comin' on.

    When you wire up a two pickup instrument (like a Tele) one pickup hot goes to one side of the switch (to the lug that is always in contact with the blade). Repeat for the other pickup to the other side of the switch (the lug that is always in contact with the blade on that side). Then the four lugs in the middle (two on each side of the switch) all get jumpered together and have a wire sent to the volume pot (or whatever your application,,,look at it as the switch 'output'). So the 4 middle lugs are all tied together and going to the volume pot. Each side will have a lug that does not get used in this two pickup appication.

    Hope that helps, GM
     
    Last edited: Feb 4, 2012
  3. guit_lar

    guit_lar Member

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    Good idea, I'll give it a shot. Thanks.
     
  4. guit_lar

    guit_lar Member

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    Well that did the trick. Such a simple thing really. Didn't realize the two sides were independent. Brilliant switch.
    Got my wiring to where I want it.
    Now if I can just figure out why the tone control works on a setting which it appears to have no connection to...
     
  5. GM Reszel

    GM Reszel Member

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    Cool, yeah as far as the tone - just follow your signal path just as you did by observing the switch. It's like flowing water - somewhere your signal is going to the tone control.
     
  6. guit_lar

    guit_lar Member

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    OK, here's a specific question, about how the current flows (trying to figure out this tone control).
    This is a two pickup guitar. The bridge pickup has 3 taps.
    The neck pickup is out of the tone circuit. Fine, that's how I want it. It is wired to one lug of the 3 way switch.
    There is an on-on-on switch present, to which the 3 tap wires from the bridge p.u. were wired. Then the output from the switch gets wired to the 3 way switch. Standard 2 pickup wiring, as in a Tele. I connected the tone control to the 3 way switch where the on-on-on output is connected. Tone works on the bridge p.u. only Fine.
    Now I make a slight change...
    I disconnect one of the taps from the bridge p.u. from the on-on-on switch (now one of the 'on' options is vacant, that's OK). I connect this tap to the 3 way switch to a separate lug, on the other side of the switch from the neck p.u. and on-on-on switch connections. I wire it so that in the middle pickup position, I'm getting the neck p.u. along with this third tap from the bridge. Tone control still connected to the lug on the 3 way switch where the remaining 2 taps of the bridge p.u. are routed via the on-on-on switch. Looks to me like the tone control is isolated from both the neck p.u. and the tap from the bridge p.u. that doesn't go through the on-on-on.
    Everything works great. Just what I wanted.
    The mysterious thing is that the tone control affects not only the bridge p.u. taps from the on-on-on (which it is directly connected to), but also the middle pickup position (which as I said is using the remaining bridge tap along with the neck). It appears to me to not have any connection to it...
    The funny thing is that this is how I wanted it to work, and I was wondering how I was going to do this...
    The question is: does having the tone control connected to the 2 taps from the on-on-on switch somehow also affect the third tap (I suppose because after all they are coming from the same pickup)?
     
  7. Sensible Musician

    Sensible Musician Member

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    guitar_lar you are obviously interested in guitar electronics. let me show you a very fast shortcut

    get some tools - for guitar you need bare minimum a digital multimeter and an analog ohmmeter (or multimeter). analog meter can be any old POS - it's a crude instrument just for checking winding direction of a coil w/o taking it apart. for DMM search for old threads, or just get a fluke and save lots of time and money on worry and replacement. the only things you really need to measure for basic guitar stuff are resistance, capacicance, voltage, and continuity. if you start winding your own pickups you will want to know the inductance of coils and the strength of magnets. but to get started just get the best meter that makes sense to your budget. if it's $5 at a pawn shop, fine - at least you can compare relative values between components; and by the time you get frustrated with a cheap meter a good meter will be worth much more to you

    next get a basic electronics book. anything that appeals to you will do - guitar is close to 100 years behind current technology, so there is literally no chance that any book still in print will be incomplete regarding what you need to know. you might find this fun:
    http://www.amazon.com/gp/product/0596153740/

    you can probably grok the critical stuff in a guitar in a single sitting: current flow, resistance, capacitance, a simple switch, low pass filter... that's enough for a lifetime of conventional strat mods, anyway LOL

    there's a feeling that's been knawing away at me since i started coming back to this forum recently - that i should do something to help other guitar players who need just the basics of electronics.

    there are many guitar-specific books in print already, but none of them really fits this apparently large group of us who are looking at drawings of pots and pickups instead of schematics...

    k i just did a search for anderton's diy projects for guitarists and i see that there is now a kindle version and the helpful part i wanted to point out - a simple preface on reading a schematic of a guitar - is included in the free sample. you can download desktop kindle reading software from amazon and get this for free. that might be enough to get you started!

    anyway, we'll never understand the flow of electrons by staring at the physical objects across which they flow. i see this every day here - someone wants to start tinkering with guitar electronics and they get every bit of advice but the one they need: learn basic electronics - like elementary school level electronics. that's all we need for basic guitar mods

    i started a blog a while back but my dedication to it wasn't enough to keep it up, so i took it down. maybe if i can really muster some gumption i'll make some youtube vids or something...

    but in general, i recommend to anyone wanting to tinker, get a few basic tools and really basic instruction. if you shop sensibly you can tool up and buy a book for less than the price of yet another pair of boutique humbuckers that none of us really need, but we all know we're gonna buy anyway LOL
     
  8. guit_lar

    guit_lar Member

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    Sensible Musician,
    Thanks for your good suggestions.
    I'm interested in anything technical in music to the degree I have to be. In this case, I just wanted something custom and couldn't see anyway to do it without some understanding.
    Besides, I hate working on anything without understanding the guts of it.
    I already have a DMM. Several years ago I built an Allen amp kit (Class Act, which I'll soon be trying to sell).
    GL
     
  9. epluribus

    epluribus Member

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    Basic electronics...very cool if you find a good starter text, but big bonus-points cool if you run to a yard sale and get an old Radio Shack Learning Lab. It's a kit with a 9-volt perfboard and a whole pile of resistors and caps and transistors and thingies that you simply plug into the perfboard and make all kinds of really cool circuits. You can even copy simple FX circuits if you Google the schematics.

    [​IMG]

    The instruction manual is good for telling you how to put all sorts of different circuits together, and inexplicably AWOL about telling you why any of it works. But it's very easy...get out your basic textbook as per the messages above and an inexpensive Digital Multi-Meter (DMM, one that does capacitance too) and measure the actual results to see if you did your equations right. Lights'll come on quick.

    As for your switch in the OP, take your nice new DMM and simply use the Resistance function to see what makes a connection at each switch position...it'll make sense quickly. Then pull up a basic Strat wiring diagram and you'll see what the switch does when drawn graphically.

    Wanna really learn your stuff...for free? It'll take you a few weeks, but good old US Navy NEETS will walk you through step-by-step!

    --Ray

    Oh yeah...Easy Way To Graduate To High-Voltage Tube Circuits Without Dying Dept.: The first time you crack an amp open, do it with a tech or a knowledgeable builder watching you do it. They can show you first-hand how to stay alive. Failing that, stick to nine volts!
     

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