Wiring a 5-way switch - is this a problem?

axisus

OK, so I'm working on producing a wiring diagram for my new guitar build. It's pretty complicated due to the fact that it has magnetic pickups, a piezo bridge and a sustainiac. I am basically trying to join a fishman/piezo plan with a sustainiac plan, and here's the thing that I'm not sure of: Is it OK for wires from both 'systems' to go to the same point on the 5-way?

Here's a bit of the diagram. Magnetic and Sustainiac wires are thicker with curves, and Piezo wires are thinner with right angles. As you can see, two terminals currently have wires from both. 

Problemo?????

ICBM

Yes, it's a problem. It's unlikely you can simply connect the different systems together and have both work properly. You will most likely need a Superswitch.

What output are you trying to achieve - mixing the piezo and magnetics, or separate on a stereo splitter cable?

Andyjr1515

Other folk will know better than me, but I would have thought that would be a big problem.  Eg, the piezo signal would have effectively a variomatic-style induction coil attached (in the form of an earthed humbucker ) 

Andyjr1515

Can't you wire it just like a three pickup strat, substituting the three pickups for the three system feeds?

ICBM

Andyjr1515 said:

Can't you wire it just like a three pickup strat, substituting the three pickups for the three system feeds?

No. In the combined positions you'll still have different systems with different output impedances connected together.

Actually there are only two systems - the Sustainiac works with the magnetic pickups. But in order to combine magnetics and a piezo, you either need to isolate the systems from each other and connect them to different outputs - either two jacks or a TRS/stereo jack - or to use a preamp which can mix them to mono, like the Fishman Powerchip.

I think it still should be possible to do that with a standard 5-way providing you're using one side for each of the systems.

Do you want to mix or separate the magnetics and piezo?

What five settings do you want on the 5-way?

Sporky

Also you need to make sure that when the Sustainiac is on, only the bridge pickup is connected. I assume you could have the piezo working as well, but I don't know how co-operative the Sustainiac will be if it's being fed the piezo signal.

ICBM

The simplest way to do it is treat the Sustainiac and the magnetics as a standard system using the mini-switches for the Sustainiac, then incorporate the piezo either with a split output or a Powerchip - that will avoid feeding piezo into the Sustainiac. I have no idea if it will work or not, but if you do it that way it doesn't matter. If you're using a 5-way to get magnetic+piezo in the "bridge/middle" position then it will automatically work with the Sustainiac on since that's piezo+magnetic bridge pickup.

Ravenous

When I've seen circuits for magnetics and piezos mixed together, each of the two sources are buffered first then mixed. That way you don't have problems with impedances clashing. This means active electronics though.

These people have debated & written about it several times - see PDF of circuit at the bottom (theirs uses a blend pot though):

http://www.mimf.com/library/MIMF_preamp-05-22-2011.html

...as for the sustainiac, can't it just be permanently wired to the bridge magnetic pickup only? (I'm guessing as I've never used theirs.)

axisus

Thanks for the answers people. I'm at work right now so I'll have to post later with a better explanation. I think I confused the issue with my first post as the piezo bridge runs via a powerchip board and the magnetic stuff also goes through there at some point as well. I'll be back later - hopefully some of you are still interested by then!

axisus

OK, better explanation of setup:

A) 3 pickups (HB/SC/sustainiac driver acting as neck SC), selection via standard 5 way switch as per Strat wiring

B ) Piezo trem running via a Powerchip preamp circuitboard. This is brought in by a small 3 way switch (bypass/blend/piezo). The complication is that the 'hot' signal from the magnetic pickups runs through the Powerchip as part of the wiring. 

C) Sustainiac brought in and out with a switch

9 pin jack plug.

QUESTIONS:

In theory it should be doable with the 5 way switch and the 9 pin jack plug. Can anyone explain exactly how a 5 way switch works? eg what the 8 tabs are doing with each of the 5 positions and the 'logic' behind operation.

My other problem is the 9 pin jack plug - getting it to operate as normal with the magnetics, but also with the two battery systems (piezo & sustainiac)

Any advice gratefully received. I'm a long way from wiring still, but as it's all going around in my head at the moment it would be great to nail the problems.

ICBM

That makes things much simpler. I thought you were trying to combine the magnetics an piezo with the 5-way...

The 5-way is actually really a 3-way with two extra mechanical notches. On each side there is a common rotor and three contacts which are active in positions 1, 3 and 5. In position 2 both contacts 1 and 3 are active, and in position 4 both 3 and 5 are. On a typical high-quality switch the two sides are reversed, ie the rotor terminals are at opposite ends.

What you need to do is:

1. Wire the magnetic pickups and the Sustainiac as normal using the 5-way and the Sustainiac switch which switches the neck pickup from pickup to sustainer mode. This should have its own volume and (if you're fitting one) tone control.

2. The piezo then has its own volume control on the Powerchip which comes *after* the magnetic controls along with the selector switch. The Powerchip is wired to the 9-pin jack and automatically senses whether you're using a mono or stereo cable.

If you get the Sustainiac from Feline Guitars, Jonathan has prepared a set of instructions which are much better than the Sustainiac ones and very easy to follow. The instructions for wiring the 9-pin should be with the Powerchip.

3. Burn the whole thing and build a Les Paul Junior.

Sporky

Ravenous said:

...as for the sustainiac, can't it just be permanently wired to the bridge magnetic pickup only? (I'm guessing as I've never used theirs.)

You need to make sure that only the bridge pickup is on when the Sustainiac is on, so if you wire it straight to the bridge pickup you still need to have the Sustainiac switch also cut away from the regular pickup switch.