Difference in switching

[vwxyz67]

I have two guitars, an Ibanez SG style and a samick LP copy, that seem to be set up the same- 2 humbuckers each with their own volume and tone controls and a single 3 way switch to change back and forth. However on the Ibanez if i turn the neck pickup all the way down and the bridge all the way up, there is no sound in the middle position on the switch. Only in the bridge position. On the samick if i do the same thing i get sound in both the middle and bridge positions on the switch. I am just curious as to what makes it do this. Thanks,

Hunter

[ashcatlt]

It's likely not really a difference in the switching, but in the way the V pots are wired.

[ashcatlt]

That answer was kind of vague. Sorry 'bout that. I had 3 kids (combined age < 10) crawling on me when I was trying to type. I could have held off, but I wanted you to know you weren't being ignored, and kind of hoped I could inspire you to open the axes and trace out the answer for yourself.

So...

In the Ibanez, the V pots are wired so that their outputs (to the switch and thence to the main output of the guitar) are on the wiper. When turned down, this wiper (and therefore the main output of the guitar) goes to ground and is shorted.

In the other, the pickup is connected to the wiper, and gets shorted when turned down. The output (to the switch and thence to the main output of the guitar) is still just as far from ground as with the V at 10.

The advantage of the Ibanez is that you can make it go (relatively) silent when you want to. By shorting the main output, you severely curtail the ability of the cable to act as an antenna pumping uncorrelated electromagnetic radiation (noise) into your amplifier. On the other guitar, even if you turn both V pots down, you'll still have that antenna hanging out of your amplifier.

There are arguments either way. I'm not real up on the "tone" parts of the question. Somebody around here (I think it was JohnH or wolf, but maybe the late ChrisK) pointed out that there's no good reason to use the middle position on a 3-way switch unless you actually want both. If that's the case, why have you turned either of the V pots all the way down?

[sumgai]

Hunter,

Your Ibanez is wired in the way we call "forward", and the Samick has what we call "backwards wiring".

In short, the 'forwards' way is normal and desirable, in that it presents a constant load to the pickup, and when it's turned down all the way, it "shuts off" the amplifier's input (by grounding it). This of course is desireable for the effect of reducing noise (like buzzing) to zero - you turn down the guitar, you don't hear nuttin'.

Backwards wiring does just the opposite, in all ways. But the net effects are twofold:

a) When you select both pickups at once, and turn down one of the volume controls, you don't kill all the sound;

b) When you turn down either or both of the volume controls, you don't ground the amp's input stage, thus you get to hear all the noise that should have gone away.

If you want both guitars to act the same, then pick that does what one you want, and modify the other to do the same thing. You'll be reversing the two connections on each volume control, for a total of moving four wires - Presto! job done.

HTH



sumgai

[vwxyz67]

Thank you this has been very helpful and I just may desire the sammick to act like the ibanez. The only reason I paid attention to this is that I like to do (and I don't know what to call it) the thing where you turn one pickup off and quickly switch back and forth. With the sammick I noticed that I had to switch farther. Maybe this will solve some of the sammicks noisyness as it has always been a bit obnoxious. Thanks again, great information.

[ashcatlt]

I was going to say something about the "stutter" switching, but decided you could make it happen on both guitars, except one has to go "further"... Just like you said.

The noise is (should be, there are no abosolutes in this worold) only an issue when you're actually looking for silence out of the guitar. In this case, the ibby has the edge, I think.