Unique switching issue -- double neck instument w/multiple effect chains

[Swimming Bird]

Okay, so I have a routing problem and a number of solutions. Certainly I am missing something so I am running it by you for an opinion and ideas.

Right now, my main setup is
chain a
bass >> a/b >> >> etc >> amp
chain b

Now, my instrument is a double-neck guitar/bass (one neck is a 6-string guitar, the other is a 4-string bass). The output wiring has two outputs and a toggle to switch between necks (with a middle position). Here's the rub -- both outputs send the same signal, whether it be bass, guitar or both. I have one chain that is completely optimized for guitar and one for bass. Right now, I'm having to flip the toggle and hit the a/b at the same time.

Here are the other issues: 1) both chains have a fuzz pedal and if one is on in the bypassed chain it'll output a huge amount of noise (about the same level as the regular signal). 2) there is a very noticeable volume when the neck toggle is in the middle position. 3) it's all one body, so there's resonant 'strokes' between the necks. For example, when I hit an E, A, D or G on the guitar neck, the corresponding bass string rings.

I'd like to be able to either flick or kick once and be on the proper chain and neck.

I'm nervous about rewiring the instrument... so do I make a sub-tiny a/b switch to mount on the instrument next to the neck toggle, get an A/B/Y to at least make both chains usable whenever or rewire (myself or professionally) to make each output only send one neck or the other? Kudos to anyone with a viable option D.

[niftydog]

Sounds like an odd wiring scheme - I would definitely consider rewiring the instrument - that's the most elegant solution IMO. Aside from the fact that it outputs from both 'necks' at the same time (how incredibly frustrating and counterintuitive!) it also sounds like it doesn't ground the unused output jack which might be the cause of the noise you're getting.

there is a very noticeable volume when the neck toggle is in the middle position.

Missing a word? Is the middle position supposed to output to both jacks simultaneously? Well, assuming you mean "volume drop" then that's likely something to do with the fact that you're putting the impedances of the pedal chains in parallel with each other.

PS: thanks for posting an intelligent and interesting post!

[Swimming Bird]

Okay, so I've been watching a lot of House, MD so let's continue in that spirit.

Nifty: both outputs are sending the same signal. That is, when I toggle up I get bass out of both, toggle down I get guitar and toggle center I get both with a bad volume drop. I plugged straight into my amp and got the same volume drop at center toggle at all volumes, tones, pickup configurations and either jack.

Also, I opened up the electronics and... sigh All of the solders are sloppy and there's a huge jumble of wires from said odd wiring job. Assuming that the wires were consistent (same color wire does the same thing) I might be able to dig around and make some changes. However, I want to check something first: if I leave all wiring as is, but disconnect the guitar side grounding cable from one of the jacks, I should only get bass signal through said jack (when the toggle is up or middle), right?

I see three wires going to each jack, one each is coming from the toggle switch, the others are coming from the pickups (where I can't see the wiring). Also, the jacks are configured such that all of the terminals appear identical, as in I can't tell what's tip and what's sleeve.

[niftydog]

Originally Posted by Swimming Bird

...toggle center I get both with a bad volume drop.

Classic "circuits in parallel" volume drop. It's just a "bad practice" wiring scheme. That switch setting effectively puts both effects chains AND both sets of pickups in parallel with each other which won't harm anything, but it will have a major affect on tone and volume.

Originally Posted by Swimming Bird

...disconnect the guitar side grounding cable from one of the jacks, I should only get bass signal through said jack (when the toggle is up or middle), right?

mmmmm.... I'd have to say no. The ground is likely common between everything and just because it's disconnected at the jack doesn't mean it's connected via some other means.

A multimeter will help you sort out which terminals are which on the jacks. Wait, TRS jacks? Huh? Whack.

The wires from the toggle switch are likely the "hot" of signal wires from the pickups, and the wires coming direct from the pickups are likely the "ground" side of the pickups.

This is about where I would grab a pencil and paper and start working out how I was going to completely rewire the thing!

If you want control on a footswitch, then just wire them up as if they were two completely independent guitars. Pretend they were separated at birth!

[niftydog]

pics? Curiosity meter is off the scale, man!

[staindbass]

unfortunatly i think its been 'modified", i think a rewiring is the way to go. sounds like the way u want it is the way it originally was set up. johnny a

[Swimming Bird]

Originally Posted by staindbass

unfortunatly i think its been 'modified", i think a rewiring is the way to go. sounds like the way u want it is the way it originally was set up. johnny a

No dice, bought it new.

Sorry about the cell pics. Also, couldn't get a clear pic of the jack.

[SpankyPants]

Hhahahahaha

[baalroo]

that's a freakin birdsnest if I've ever seen one... total screwball clusterF. Take it to a "pro" and they should be able to do a MUCH better job and wire it up PROPERLY so each output is for a seperate neck. Looks to me like the new guy at the factory did yours.

p.s. I can't stop laughing a this, I showed my GF who knows nothing about guitars or wiring and she even laughed... sorry to make light of your misery but it should be a cheap and easy fix so I don't feel too bad.

[niftydog]

In the word of the immortal Shaggy - Zoiks!

Rip it out, start over, aside from anything else you'll end up with a less noisy and more reliable instrument just by getting rid of that Chinese-athletics-stadium wiring!

[bongomania]

It's a Tennessee. If they spent any money on proper wiring or assembly they wouldn't be able to sell their goods so cheaply. I would look at the existing wiring as sort of a "serving suggestion" like on a cereal box- they show you blueberries, but really you have to provide your own blueberries.

[niftydog]

Winner of analogy of the week: Bongomania!!!

[Swimming Bird]

Hilarious, I know, but is there a quick-n-dirty fix? I'm finding the A/B box + toggle very cumbersome and I think I could work it by using my homemade double kill box (basically a poor-man's A/B-Y) and having each neck use its own jack, maybe with some velcro under the strings as a damper.

Glad I could provide so much entertainment

[niftydog]

Well, what's acceptable for "quick and dirty"? The guitar itself is at fault, IMO, so the Q&D approach is to rewire the toggle switch.

Tell me if this is right:
switch in up position = bass output from bass jack, guitar jack 'muted'.
switch in mid position = bass output from bass jack, guitar output from guitar jack.
switch in down position = bass output muted, guitar output from guitar jack.

[ehque]

Actually, you can use a stereo jack to forgo the switch at the guitar, and use an A/B/Y box at the end of both your effects chains.

Bass neck -> Bass Chain -> A
Guit neck -> Guit Chain -> B

Both into an A/B/Y box, then -> amp.

This will save you having to switch and stomp. You'll need a stereo jack and a stereo-to-mono cable (or 2 jacks and 2 cables will do as well).

[Swimming Bird]

nifty: exactly. Q&D approach would be someone ok-ing my remove one ground from each jack idea, but rewiring the toggle might also work.

ehque: that would also be acceptable. All I would need to do is switch one of the jacks to a stereo and move the wiring over as is, correct?

My current switching setup would accommodate this just fine as the chains end at the aforementioned double kill, double switch box.

Would either method relieve the volume drop issue?

[niftydog]

As long as you don't wire the two circuits (ie; the guitar circuit and the bass circuit) together in parallel you'll avoid the volume drop. Like I said, you essentially need to treat it as if it were two different guitars. You won't be able to avoid having the grounds common though because they'll connect via pedals or your amp.

Be careful though, you want to avoid the parallel wiring, AND retain the ability to mute the neck you are NOT playing. The approach suggested by ehque (stereo jack & stereo to mono cable into a regular ABY box) will result in the circuits being wired in parallel, and switching the AB box won't mute the 'other' neck!

Removing the ground wire from a jack I just don't think will work - but feel free to try it out - you can't hurt anything. I think you're best bet is to rewire the toggle switch. Gimme a bit of time and I'll sketch something.

[niftydog]

Oh yeah, and all of this depends greatly on what type of toggle switch you have - those three position switches come in a few types. There's the type that has both switch poles 'on' in the middle position, and the type that have them both 'off' in the middle position. Sounds to me like you've got an 'on' type... <thinking...>

[niftydog]

jebus... that's a problem because you really want the signal to be grounded - and therefore muted - when it's not in use.

Thinking out loud here... ideally this is what I would do:

  BASS SIGNAL -o
               __--o- BASS JACK
          .----o
       GND|
          '----o
               __--o- GUITAR JACK
GUITAR SIGNAL -o

So, as shown above you'd have guitar out of the guitar jack, bass jack would be muted (grounded).

Now, imagine the above with both switches moved to the upper contacts - now you've got bass out of the bass jack and the guitar is muted.

So that is the 'up' and 'down' positions, now the 'middle' position is where it gets a bit tricky. With a 'centre on' type switch, both contacts are connected, meaning everything is grounded. Not so good. With the 'centre off' type, nothing is connected, also not good.

Shhhheeeeeet!

[niftydog]

Ok, this ought to work. Wire the bass signal directly to the bass jack, and same for the guitar jack. Now we use the switch as a selective mute switch (rather than something that routes signals here or there.) For this to work you'll need a 'centre off' type of switch.

  FROM BASS CIRCUIT--------.-------TO BASS JACK
                           |
                           |
                         o-'
                 o---o--__
                 |       o-
                ===
                GND


FROM GUITAR CIRCUIT----------.-----TO GUITAR JACK
                             |
                             |
                         o-  |
                 o---o--__   |
                 |       o---'
                ===
                GND

So, as shown, the bass signal passes directly to the jack and so does the guitar signal BUT the guitar signal is grounded, effectively muting the guitar jack output.

Imagine the switches flipped over to the upper contacts, and now the bass signal is grounded, but the guitar signal passes to the guitar jack.

Now, in the centre position, where all the switch contacts are 'off', neither output is grounded, and you'll get bass out of the bass jack, and guitar out of the guitar jack.

Anyone agree?!