Tube Amps / Music Electronics
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|8/12/1999 12:53 PM|
||guitar wiring basic question|
I read something about series and parallel wiring in two-pickups guitars such as Tele's. I'm a bit confusing because I guess that since every pickup comes with two wires they can be just in-phase or out-phase. If not so simple please explain me.
Thanks in advance
|8/13/1999 12:18 AM|
Giacomo: Single coil pickups designed to be versatile like this will many times have a 3rd bare Ground wire. With only 2 wires coming out of the pickup, one of the wires (the black one) is usually fixed at Ground. If you want to pull one of the pickups out of phase, you'd have to "float" its ground wire. In other words, you'd have to swap hot and Gnd using a switch.
You may want to take a look on the Seymour Duncan page at some of the schematics for Teles:
This might give you some ideas.
|8/15/1999 8:33 PM|
When you wire up speakers, you can either have wires going to each speaker in parallel, or you can run a wire to one speaker, and from there to another speaker, then to ground. Having them in series or parallel changes things. Although the speakers must be in phase with each other, there is no reason why the red terminal MUST be the input, and the black terminal MUST go to ground. These are just two connector terminals on the speaker.
It works the same way for pickups. They can be wired in parallel, or end-to-end like speakers (series). Since it is easier to do, and since it also reduces some problems such as treble-loss and radio interference, almost all guitars come wired with the pickups in parallel. Since any pickup that has a metal cover (Gibson-style humbuckers, Telecaster neck pickups, etc.) usually connects the cover to ground, you will find these pickups have a single wire with a shielding around them. Even when there is no metal cover, some humbuckers come with a single-conductor shielded wire. To change which end of the pickup is ground is a difficult procedure. Because of this, it is difficult to wire these kinds of pickups in series.
For many other types of pickups, however, there is no single wire which MUST be ground/shield. Fender-style pickups usually have a black and white wire soldered to them, but either one can be treated as the ground wire. If you wired up two pickups like this so that:
- BLACK from pickup #1 went to ground,
- WHITE from pickup #1 went to BLACK on pickup #2
- WHITE from pickup #2 went to the pickup switch and volume control
then you would have series, in-phase, pickups. You could do the same thing by reversing the two colours.
Two things to consider, however:
1) The two pickups should be MAGNETICALLY in phase (if you try to touch the tops of the two pickups together, they push each other away)
2) You will have a louder signal, but you will lose treble, and may have more radio interference and buzzing.
Please note that series switching requires a more complex switch, or else two switches.
|8/17/1999 7:02 PM|
Many thanks for your explaination.
|8/18/1999 4:04 AM|
As far as interchanging the white and black leads of a strat pickup, you can have problems if there are any shorts between the pole pieces and the inner wraps of the coils. For Fender style strat pickups, the inside of the windings is traditionally connected to ground and the outside of the windings is the hot output. Before adding in phase or series switches I test for any shorts from the coil to the pole pieces (and rethink my strategy if any shorts are found). When shielding strat pickups with copper foil tape I will usually also ground the pole pieces unless they are shorted to ground.
There was a discussion here awhile back that maybe strat pickups would be quieter if the outer windings were grounded (and would act like a shield-right?)* On the other hand it was suggested that the sound might be different with the hot going to the inside of the coil. (I don't believe that any of those issues were resolved at all in the discussion so if you have any ideas on that they would be appreciated.)
P.S. BTW for traditional PAF-style humbuckers (made any of those?) the inside wire of each bobbin is connected to hot (or ground) and the outside wires are used for the series link. But then again there is the plastic bobbin which would keep the wire from shorting out against the screws or slugs.
* John Atcheley's theories would tend to negate any lowering of the noise level as he proposes that the audio signal return be kept isolated from the shield grounds (and ground shields as the case may be).
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