Can a SC be out of phase with a HB?

[GlennW]

Thanks everybody. I'll ground the Hag baseplate.

The P pickup sounds a lot better after lowering it.

[Mark Hammer]

???
Only if the two coils of the humbucker are out of phase, right?

Most Strat-type guitars are wired such that you can only select one or two pickups at a time. Normally, the middle pickup is reverse polarity and wired up out of phase, such that middle plus either the neck or bridge will result in hum-rejection. I can say for a fact, however, that if one is so bold as to wire up said instrument to be able to have all 3 pickups on at once, hum rejection drops by a certain percentage when all 3 are on. Why? Well, two of the three pickups (middle plus one other) will function as if they were a humbucker pair. The third coil, however, will be in phase with one of the other two, and out of phase with the other. So, because there is more hum picked up from the one orientation/polarity than from the other, cancellation is incomplete.

Where one has a SC and HB pickup on at the same time, you have the exact same 3-coil scenario. Two of the coils are sensing hum from the one polarity/orientation, and the third coil is sensing the opposite hum. The degree of hum-rejection for the two pickups will be greater than that of the SC alone, but less than that of the HB alone.

Of course phase with respect to hum is different than phase with respect to signal. While the frequency content of the hum is relatively constant regardless of the location of the pickup, frequency content of the signal depends very much on the pickup's location. Consequently the degree of audible cancellation of the signal when there is a SC and HB on at the same time will depend on the two pickups' respective frequency response and their individual locations. Were one to have a mythical guitar with, say, a 40" scale and 16 frets, and you had one skinny SC pickup jammed right against the bridge, and another smack at the midpoint of the string, flipping those two pickups in and out of phase with each other would produce (some, but...) little audible cancellation because there is little overlap in the frequency content of each PU (you can only cancel what is equally represented in both pickups).

[Sweetfinger]

Most Strat-type guitars are wired such that you can only select one or two pickups at a time. Normally, the middle pickup is reverse polarity and wired up out of phase, such that middle plus either the neck or bridge will result in hum-rejection. I can say for a fact, however, that if one is so bold as to wire up said instrument to be able to have all 3 pickups on at once, hum rejection drops by a certain percentage when all 3 are on. Why? Well, two of the three pickups (middle plus one other) will function as if they were a humbucker pair. The third coil, however, will be in phase with one of the other two, and out of phase with the other. So, because there is more hum picked up from the one orientation/polarity than from the other, cancellation is incomplete.

Where one has a SC and HB pickup on at the same time, you have the exact same 3-coil scenario. Two of the coils are sensing hum from the one polarity/orientation, and the third coil is sensing the opposite hum. The degree of hum-rejection for the two pickups will be greater than that of the SC alone, but less than that of the HB alone.

Of course phase with respect to hum is different than phase with respect to signal. While the frequency content of the hum is relatively constant regardless of the location of the pickup, frequency content of the signal depends very much on the pickup's location. Consequently the degree of audible cancellation of the signal when there is a SC and HB on at the same time will depend on the two pickups' respective frequency response and their individual locations. Were one to have a mythical guitar with, say, a 40" scale and 16 frets, and you had one skinny SC pickup jammed right against the bridge, and another smack at the midpoint of the string, flipping those two pickups in and out of phase with each other would produce (some, but...) little audible cancellation because there is little overlap in the frequency content of each PU (you can only cancel what is equally represented in both pickups).

THE ORIGINAL QUESTION REFERRED TO SIGNAL PHASE AND HAD NOTHING TO DO WITH HUM CANCELLATION. (sorry for yelling) which is why any of the statements about single coils always being out of phase with humbuckers is misleading at best. All Strats are wired with the pickups signal outputs in phase even though in the vernacular many people refer to positions 2 and 4 on a Strat as the 'out of phase' sound. Those positions are very much in phase.
I also disagree with your assertion that when flipping the phase on one of two pickups, the frequency differences due to positioning will result in 'little audible cancellation'. Flip the wires on the strat middle pickup and you will hear PLENTY of frequency cancellation, same with any two similar pickups regardless of where you place them on the guitar. There's plenty of frequency overlap, the reasons for a less than perfect cancellation have more to do with output levels than frequency content. There is never going to be a full cancellation of signal because as you go up higher in the frequency spectrum the pickups themselves cannot accurately track those phase relationships but content wise, the signals are more alike than different. Of course, if you start changing to two dissimilar pickups, like a single coil and a humbucker, you will get some differences due to frequency content, but these differences pale when output levels are adjusted.

In fact, the secret to getting a good 'out of phase' sound with two pickups is to work with the output LEVELS to actually reduce the cancellation down to the barely/slightly audible differences. Its actually pretty tough to get any two pickups adjusted so that they have a good sound and level by themselves AND connected out of phase. In guitars without separate volume controls like Teles and Strats, I will install volume pots and adjust the pot to where the phase cancellation is subtle, usable, and musical. I'll then remove the pot, measure the value at rotation, and permanently install a resistor that simulates the pot.

[David Schwab]

???
Only if the two coils of the humbucker are out of phase, right?

They always are, otherwise it wouldn't buck hum.

The only reason they don't sound out of phase is the reverse magnets, which puts the signal back in phase.

[David Schwab]

All Strats are wired with the pickups signal outputs in phase even though in the vernacular many people refer to positions 2 and 4 on a Strat as the 'out of phase' sound. Those positions are very much in phase.

Yeah, people started calling that out of phase... it's notchy sounding, but it's in phase.

The other thing is everyone assumes the middle pickup is always RWRP, but they never used to be before 5 way switches became standard.

The guitar was designed to only have one pickup on at a time.

[Mark Hammer]

Sweetfinger,

This is why I referred to the "mythical guitar". On a normal guitar, pickups are close enough to each other that there is considerable overlap in what they sense from the string. Under those circumstances, there WILL be cancellations produced in those areas where sensed content is similar, and phase is reversed. The mythical guitar I described is one which would be engineered to have minimal overlap in sensed content between the bridge and "neck" pickup.

If memory serves, didn't Hamer produce a guitar in which the neck and bridge HB pickups were wired out of phase but you could adjust the balance between them to make the out-of-phase tone go away? I know when I adjust the balance of two pickups out of phase with each other, you can easily resume a normal in-phase tone by simply reducing the level of one of them a bit.

I guess the point I want to make is that one needs to factor in three different phase relationships:

1) The phase of various coils with respect to their hum-sensing.

2) The phase of separate pickups with respect to signal sensing.

3) The phase the string itself presents to the pickups at any given frequency with any given fretted note.

You can have strings which present identical information to two separate pickups that is summed, information presented to two different pickups that is contrary at source...but still electronically summed, and information presented to multiple pickups which is identical but produces electronic cancellations. It's not ALL in the strings and not ALL in the pickups.

[black_labb]

reguarding the "out of phaseness" of strat position 2 and 4

there is some cancellation, but that doesnt mean its out of phase. the cancellation ocurrs to harmonics for which there is a node between the pickups that are playing. this is not considered out of phase.
for a normal single coil pickup the sensing of the string is not one specific spot, its a area along the string that gets bigger as the coil widens. if there is a node within the sensing area, then some of the frequency which that node is related to will be cancelled out. does that mean that the coil is out of phase with itself? no, its just an effect of coil shape. its one of the reasons a wider coil will sound "warmer" than a narrow coil (ie p90 is wide and fender singlecoil is narrow).

[David Schwab]

Also, besides cancelations, you have some reinforcements of certain frequencies going on.

Another thing is now you have two pickups loading each other.

Lots of stuff going on.