strange problem w/ series/parallel

[fender_mod]

i did a series parallel mod on my bass and when i turn my volume knobs one way in series to raise the volume i have to turn them the other direction in parallel to get output. so the problem is when i switch from series to parallel i have to then turn my knobs in the opposite direction. i have stacked vol/tone for each p/up, could the problem be somewhere in the wiring? has anyone encountered this before?

[RyreInc]

Not sure about this, but a possibility could be that your volume pots remain unchanged when switching between parallel and series.
In parallel, when volume is all the way up, one end of a pup is connected to the jack, the other to ground. Now, when you switch to series, if those connections still remain, you will be shorting the pups to either ground or lead respectively, depending on which pup we're talking about.
So, when you turn the volume pot in the other direction, you add 250k (or whatever) resistance between the shorts, allowing function in series mode.

What you need to do is to consider the volume pots as a part of the pickup, and include these in the series/parallel switching.

[lug]

You could have reversed the phase on one of the pickups. Reverse the wires from just one of the pups to check if this is the problem. If they are reversed, you will get a very "thin" sound with both maxed.

[luknfur]

Originally Posted by fender_mod

... p/up, could the problem be somewhere in the wiring? has anyone encountered this before?

FWIW:

Not sure but I think you have a first here.

I'd bet money the problem is in the wiring.

From what you describe logically the issue would be in the switch wiring. Also probable since wiring is very tight in a switch so prone to both poor contacts and shorts. Also different type of switches are used for different wiring so you may have the wrong switch for the task at hand - from recall should be just a simple DPDT toggle.

Also if you changed anything else in the circuit besides the switch, you may have more than one issue going at a time.

[fender_mod]

i know its a dpdt, ordered it from all parts. i have my pups going into a selector switch first, then vol/tone pots. do i need to wire the pups into the vol/tone first and then the selector switch? i have a diagram i can post if it will clarify.

[GlennW]

That's where it's screwed up. You need to do the S/P deal before going to the selector switch, then to the volume and tone pots. It's been a while since I messed with that stuff, but I'm pretty sure that when in series one or two spots on your selector switch won't do anything - that's because you've effectively made them into a single pickup. There's a site called Guitarnuts; they're Strat oriented, but have a lot of good wiring info.

[PilbaraBass]

post a schematic...
we'll have a look at it and straighten you out.

Glenn is right in that when you select series, you effectively have one pickup and one working V/T knob set. The switching is really done on the bridge pickup, where in parallel, it goes to it's V/T pots, when in series, the signal goes to the ground of the neck pickup.

So the ground of the neck pickup is switched between ground, and the hot of the bridge pickup.

The hot of the bridge pickup is switched between it's V/T knob set and the "ground" wire (non-hot) of the neck pickup.

Does that make any sense?

[sunbeast]

It doesn't make sense that a miswired series/ parallel switch would cause the volume knobs to "switch" orientation. If you wired the volume pots correctly, one side (one lug on the pot) should always be attached directly to ground- which could not be affected by the series/ parallel switch. If you leave the volume knob all the way down, then you should get no volume whether or not anything else is miswired- if this is not the case, then you haven't wired the volume pot to ground.

Also, the switch should be wired before the pickup selector switch and volume pots. This will mean that only one volume knob will have an effect when you are in series mode.

I can't picture it exactly, but I bet you A. just switched 2 wires on the selector switch or B. miswired one or both volume pots.

I guess you should just post a picture or just rewire it with one of the many diagrams on the internet- there are a few different ways to wire the switch by the way, but they should have the same effect.
Karl Zickrick

[fender_mod]

Originally Posted by sunbeast

It doesn't make sense that a miswired series/ parallel switch would cause the volume knobs to "switch" orientation. If you wired the volume pots correctly, one side (one lug on the pot) should always be attached directly to ground- which could not be affected by the series/ parallel switch. If you leave the volume knob all the way down, then you should get no volume whether or not anything else is miswired- if this is not the case, then you haven't wired the volume pot to ground.

Also, the switch should be wired before the pickup selector switch and volume pots. This will mean that only one volume knob will have an effect when you are in series mode.

I can't picture it exactly, but I bet you A. just switched 2 wires on the selector switch or B. miswired one or both volume pots.

I guess you should just post a picture or just rewire it with one of the many diagrams on the internet- there are a few different ways to wire the switch by the way, but they should have the same effect.
Karl Zickrick

i did actually wire the selector before i wired the pups series/parallel. heres a link to the diagram i used, i lost he jpeg file when i had to reboot my computer. the pic is at the bottom of the post. im not really sure what to do, im almost certain the wiring is correct according to the diagram in the post. im stumped on this one so any help would be really helpful

heres the link, the post with my diagram is at the bottom of the page
wiring up three pickups?

[sunbeast]

I'm not completely sure about this, but... is the output wire attached to the middle lug of the center pickup? The way it looks to me, when it is in series, you control volume with either the left or right volume knob, depending on which pickup is chosen with the on/off/on switch, is this correct? I think that the output should be connected to the left lug of one of the volume pots (maybe it is and I just can't understand the diagram?). If it is connected to the center of the center volume pot, in series you will be in effect running the signal through one volume pot, and then through the center pot but at the opposite orientation. This could cause a similar problem as what you are describing, although if those volume pots all have their right lugs attached to ground, they should still send no signal when turned all the way off. The effect you are describing could be the loading of one volume pot into another (I don't really know how to explain that better).
Anyways- if the hot wire is attached to the center lug of the center volume pot, switch it to the left lug of any of the volume pots- and I bet that will fix your problem! If it is already connected to the left lug of one of the pots, then I am stumped....

Karl Zickrick

[RyreInc]

My best guess is to double-check the ground of the middle pup, make sure it is connected to the other grounds, and to the jack sleeve.

If you have to turn the pots the other way to achieve output, then this should mean that something that should be grounded isn't--otherwise you would have no signal.

Also, note that the lefthand lugs are the ones that connect together to the output, not the middle lugs.

The diagram is correct as far as I can tell.

[fender_mod]

yes i do have the wire to the middle lug of the pup, so that makes perfect sense why im experiencing the problem. im about to settle down and work this out, prolly post something later tonite on how it went. really appreciate all the help im getting. thx.

[fender_mod]

problem solved. thx for the help.