phase...out of phase.....series.....paralel......

[MrHyde]

hey guys, what's up.
I want to ask u guys if u can explain to me what does phase and out of phase pups mean? and paralel and series mean ( wiring) cuz I always read about that stuff I think I know but Im not shure so I better ask cuz I don't want to be a dumb *ss all my life U know

 

[beej]

Lots of questions in here. Someone yell at me if I'm getting too nerdy. (Let the jokes begin ...).

Phase

First, we need to talk about waves in general. A wave (sonic, electrical, ocean, etc.) increases/decreases in amplitude over time. We measure the wave's cycle in degrees - 360° is a full cycle, 180° is a half-cycle, etc.

When two waves are "in phase", they have the same frequency and start their cycles at the same time. However if the waves start at different times, they're said to be "out of phase" by some degree. See this photo for illustration:

In general, if you combine waves that are in phase, the amplitude of the overall wave will increase. However if you combine waves which are out of phase, portions of the waves will cancel each other out. If you take a wave and combine it with the exact same wave that's 180° out of phase, the wave will cancel itself out entirely.

As it relates to electric guitar- the mechanical vibration of the string is a sine wave. The vibrating wave through a magnetic field induces an electrical current in the winding of the pickups. The produced electrical current is a wave that looks just like the wave of the vibrating string(s).

Phase isn't normally an issue with a guitar, as most pickups are wired up to have the same phase. (If you combine pickups that are out of phase much of the signal gets cancelled out. A cool effect. Some guitars have in/out of phase switching.) By virtue of the locations of pickups at different points under a vibrating string, phase issues do come into play when combining pickups.

Phase IS used to cancel out noise, though. On a humbucker, the second coil has a magnet with the polarity reversed. The windings around the coil are also reversed. These two opposites (magnetic field and winding) lead to a current that's in-phase with the other coil of the humbucker. However- stray noise that's picked up by each coil (the windings act like antennae, picking up stray electrical noise) is out of phase (b/c the windings are backward). So when you combine the two coils, the guitar signal is in phase and the noise is out of phase. The noise is thus cancelled out and presto, you have the basics of the humbucking pickup. You get the same effect when you combine the bridge or neck single coil pickup with the middle pickup in a 3 pickup guitar - the middle is reverse wound to give you the humbucking effect in the combined positions.

Series / Parallel

These terms refer to how two electrical components (coils, in this case) are wired together. When the output of one coil feeds the input of another coil, they're said to be "in series". When the inputs are wired together and the outputs are wired together, they're "in parallel".

A guitar pickup is an "LCR" circuit. It has inductance (L), capacitance (C) and resistance (R). All three of these electrical properties help define it's sound. Change one property and you'll affect the output frequencies. For example, adding more resistance (like increasing the size of the volume pot) will shift the loudest frequencies of the pickup upward, causing the output to be more trebly, etc. Increasing the inductance will shrink the window of frequencies passed by the pickup, causing more of a midrangey sound, etc.

Describing the overall effect of the guitar + cable + amplifier is complicated, so let's talk about the resulting sound.

Standard humbuckers are wired up in series - one coil feeding into the next. The combined output is louder than each of the coils on it's own.

Most single coil guitars are wired up in parallel in the in-between positions (the "quack" positions). What happens when you wire coils in parallel is that the coils act on each other- you reduce the inductance to 1/4 and the resistance to 1/2 of what each coil had (assuming they're identical coils). The net effect is like a high-pass filter- you get a lot of highs and lowered output. (Inductance is a big factor with pickups- it helps determine what frequencies are passed by the pickups.) This is also why the "quack" sounds are quite shrill and need a lot of highs to reproduce properly.

One thing that's thrown around from time to time is to modify a guitar to allow for series or parallel wiring. In the case of a humbucker, you can wire it up to have the two coils in parallel rather than series. This gives you more of a single-coil type sound out of a humbucker. You can also wire two single coils to be in series in the usual 2 + 4 strat positions, rather than in parallel which is how they're normally wired.

Hope that's not rambling too much.

J.

 

[Beth]

nerds rock

 

[mbgreene]

Beej rules!!!

 

[Adwex]

nerds rock

Hot chicks who like nerds rock.

Will you marry me?

 

[francric]

I'm A YELLING at Ya!!!!!!!!!!!!!!!!

 

[beej]

Jeez Beth ... look what you've started ... !

 

[Beth]

 

[GWDavis28]

Beej rules!!!

I second that!!!!!

Glenn |B)

 

[MrHyde]

HEll YEAH MAN!!!!!.... that's what I was talking about!!!
U rock dude!! thanks a lot!!!

 

[nobozos]

Beej is absolutely 100% correct on all counts. Very well written Beej. Check out the Burns Brian May Signature guitar if you want to have your collective electronic minds blown. Each pickup has a switch, which if I am correct, the configuration is: Up=reverse phase
Middle=off
Down=normal phase

Since all 3 pickups have a switch, the ability to put the pickups in and out of phase with each other gives you a lot of tonal flexibility. Pretty cool setup.

 

[beej]

Thanks man

Yeah- that's exactly the guitar I was thinking of! I've never been able to play one in person, but I've heard some cool sounds from it on videos, etc.