6 way rotary switch for 3 singlecoils

[dunkelfalke]

hello forum

here i've got a wiring diagram



is this switch the right one?

www.banzaimusic.com/Rotary-Switch-1-level-1x2x6.html

if not, can someone please point me to the correct switch?

thanks in advance

[ashcatlt]

I think, if we put our heads together, we can do it with the switch you've linked. Your diagram wants at least 3 poles, though, so it won't work as shown. Pretty sure we could find a switch that will work from mouser, but you're on the other side of the world...

[JohnH]

Yes, it does need three poles, which means a two layer switch (for 4 poles). Alpha make them, and I got some from mouser via a US friend, but maybe you can find a euro supplier.

A single layer switch is more common, and a 2 pole 6 position is a standard type. You can use that to get those combos, with the exception being the all 3 at once, which you would have to exchange for another 1 or 2 pickup sound such as middle only (which is not on the diagram currently), or maybe 100% bridge plus a reduced amount of neck (a good option IMO).

It is also possible to get all those combos with a 2 pole switch, if the 2 and 3 pickup combos are series wired rather than parallel

John

[sumgai]

dunk,

Looks like a good, simple diagram, I think it will work as you wish.

The switch you want/need is available from Banzai, go here:

www.banzaimusic.com/Rotary-Switch-2x4x6.html

Unless I'm no longer able to correctly convert euros to dollars, that's a pretty darn good price, too! ;D


HTH



sumgai

[dunkelfalke]

Thanks a lot, guys!

[dunkelfalke]

Jan 31, 2010 21:04:26 GMT -5 JohnH said:

A single layer switch is more common, and a 2 pole 6 position is a standard type. You can use that to get those combos, with the exception being the all 3 at once, which you would have to exchange for another 1 or 2 pickup sound such as middle only (which is not on the diagram currently), or maybe 100% bridge plus a reduced amount of neck (a good option IMO).

The second option sounds very good, and I like this switch better anyway, because of its smaller size.

Oh, by the way, what would be the best wiring to add, let's say, a piezo signal to the mix after the volume pot (so I can turn the volume all the way down to use the piezo sound exclusively) with a DPDT switch (push/push volume pot)?

[JohnH]

That does look like a good deal on the switch.

Piezos need some preamp to get a suitably robust tone and level. If you can get that as a system from Ghost or someone, then I would suggest to follow that with a simple one transistor blender to mix mag and piezo in any proportion you want, and this should be before the volume pot. It could be the module used here:

Blender module

Without something like this, it is hard to match the different impedances from an active piezo and passive mag pickup system

John

[dunkelfalke]

Sorry, I forgot to add that I am going to use active pickups for this guitar. For the piezo, I am thinking about this preamp: www.cafewalter.com/cafewalter/fetpre/graphics/pzpreii_schem.gif *

I am thinking about following: active single coils going to the rotary switch, then to the volume pot. After the volume pot, the piezo signal after a preamp can be added with a push/push switch, after that the signal goes into an active tone expander.

I'd prefer to use the first switch(the single layer one) and no additional controls (Need as much space as possible and don't want to drill another hole for the blend pot). Is this combination realistic? If yes, what would be the best way?
Thanks in advance.

* I have difficulties to source the MMBF5457 JFET. Is a 2N5457 a valid replacement? Are there better (better sound, less noise) possibilities?

[JohnH]

OK, im not familiar that JFET circuit - ive seen it before but havent tried it. It would be worth typing it into 5Spice to see what it does in terms of gain. I would say that those JFETs are the same as 2N5457. That is the type that I use, but I use them in a simpler class A circuit. It should give low noise.

If you have active mag and piezo signals, and a push pull to switch the piezo in and out, then mix mag and piezo via about a 47k resitor form each, then to the tone expander. Do you have specs on that? - ie a circuit diagram, or at least input and output characteristsics

For your single layer switch, its all OK but you do need to pick another 1 or 2 pickup combo to replace the all three pickups combo, which cant be done with two poles.

What you want is mostly all possible, with a bit of thinking.

John

EDIT - I did check out that JFET circuit, it is just a buffer and actually reduces signal level. He designed it to suit his system, but your piezo might need something different depending what it is - in the schematics section you can see where I ended up adding a piezo.

[dunkelfalke]

"100% bridge plus a reduced amount of neck" sounds good, because the guitar has got the same pickup layout as this one: www.guitarmaniacs.de/html/users/catharsis/uqDbk-uqDbk0414_122203.jpg

so mid position alone wouldn't make much sense.

i haven't got specs of the tone expander, but it is this one: www.artecsound.com/pickups/electronics/exp.html (the pot version)

[JohnH]

OK, I can sketch you a switch circuit if you wish

See my edit above on the JFEt piezo circuit - youd need to try it with your piezo, maybe omit the two 10k output resitors to keep more of the signal

[dunkelfalke]

Oh yes. Wish I could buy you a beer for that.
I checked your schematics. Unfortunately the board is way too large to fit in. For all practical uses my active pickups are EMG S clones by Schaller.

What about this circuit?
liutaiomottola.com/PrevPubs/Piezo/figure8.JPG

What are the diodes for?

[dunkelfalke]

by the way, what do you think of this one?
cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=260526617239

[JohnH]

the diodes are to protect against over voltages and reversed batteries - not really needed with a JFET circuit. That circuit could be built small and gives about a x2 gain.

What will your piezo pickup be?

(good night - Im off to bed now)

John

[dunkelfalke]

If I can find the pickup I bought 5 years ago - two pickups connected to each other actually - I am thinking to stick them to the vibrato system plate from beyond, one of the left side, one on the right side. But better suggestions are always welcome :-)

By the way, what FET would you recommend for the circuit? The author suggests "2N4392, 2N4393, or something similar". Unfortunately I can source neither easily.

Thanks for the information and good night!

[dunkelfalke]

Another question. Since I can't find my piezo pickup, I'll have to order a new one. Would it make sense to order, say, three of them and then place two of them in the each side of the vibrato plate and one of them at the body wood and then connect them?

[JohnH]

I will look that JFET up, but it looks like it is in a circuit that would work fine for a 2N5457.

If you are still looking at different piezos, I suggest taking it step by step, and get the piezos going, and start by plugging them into the amp directly, or into a pedal with a high impedance input, to get a sense of how loud they are in comparison to a mag pickup. Then you can decide how much preamp gain is needed and that will affect the circuit that you use. The first preamp you showed had a gain of about 1/2 while the second is about x2. When I built a piezo in, I needed about x3, plus some tone EQ (see adding a piezo pickup in schematics)

John

[dunkelfalke]

Okay, I will do that.
2x amplification is probably exactly what I needed because... well, I've borrowed the guitar where those active pickups currently are to a professional musician for a gig, and afterwards he complained that my guitar is so damn loud ;-)

[dunkelfalke]

Some guy at a german guitar board suggested BF245A, J111 or J112

[dunkelfalke]

Uhm, I really hate to sound impatient, but... any news?

[JohnH]

Hey Dunkl - sorry I hadnet realized you were waiting! I havent used those transistors, most likely they are suitable, but the J112 looks most likely to do similarly to a 2N5457. It will affect resistor values in the circuit and also gain.

The single transistor circuit that you posted can have its gain increased by adding a resistor and cap from source to ground (lowest transistor lug on the diagram)

But my point above still applies. Unless you are buying into a piezo system with its own preamp, then we dont know what preamp you need to build untill you experiment with the piezo in the guitar.

John

[dunkelfalke]

Transistors are not my primary problem, I can figure that one out by tinkering. The wiring for the rotary switch is ;-)

[JohnH]

Oh yes, I offered a sketch so here it is:



This is where the all 3 combo is replaced by Bridge with reduced neck, and Ive put them in what seems like a good order from dark to bright. The diagram assumes that when you combine your active pickups in a normal way, it is OK just to join the outputs together as with passive pups.

Pickup grounds all go to ground.

The reduced neck setting is through the resistor, and some more tinkering will be needed to pick a good value. I'd expect a suitable value in the range of 1/2 to 2x the active pickup output impedance, which you should find on specs.

John

[dunkelfalke]

Thanks a lot!

Unfortunately I've got no specs for them at all because the company they were made for went out of business years ago. Is it possible to measure the output impedance with a multimeter?

[JohnH]

For EMG actives, I see they spec an output impedance of 10k, maybe yours are similar but you can’t measure it with a meter. Since this will be a choice anyway as to what sounds best, maybe try with a selection of resistors up to around 20k-30k, or hook up a 50k pot and adjust to suit. You could build a preset pot into it, or measure your selected resistance after testing with a temporary pot and use a fixed resistor.

Also, have you got these pups wired in now, and if so can you confirm that when you select more than one, it is OK to join their outputs directly, as with passive pups? Anyone else have a comment on that? (I’m thinking it is usually not a good idea to link two active amplified outputs together, but maybe active pickups already have suitable output resistors so two do not fight each other.

[dunkelfalke]

I had them working perfectly fine with the tone monster wiring nearly since I joined the first guitarnuts (that are the pickups of my blue Revelation) so I think it will work. Shall I try a trim pot there?

I am going to gut my other guitars to give my new Revelation ATX the best parts I've got.

[JohnH]

OK, a trim pot might be a good way - maybe you can quickly rig up some test first without he rotary, just select the bridge pup and put pot between hot outputs of bridge and neck - then you can test the sound of full bridge with neck bed into it controlled by the pot

John