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Post by perfboardpatcher on Dec 19, 2015 8:46:37 GMT -5
Hello guys, I have been reading this topic, rabidgerry part in particular lately and got me thinking. Perhaps my idea is flawed. Or it has already been considered, tested and rejected for whatever reason. Please let me know what you think of it. How would the the humbucker itself perform as a (quasi) dummy coil? It seems to me that in a HSS configuration the HB with its coils in series and wired out of phase (for guitar sound) could function as a dummy coil in combination with the single coils. (Scientific prove/ Rough calculation/ wishful thinking  : Assume Impedance single coil=1Z, Impedance humbucker=2Z, Hum signal voltage single coil=1V, Hum signal voltage humbucker coil=-2V Resulting noise voltage= (1V x 2Z/3Z) + (-2V x 1Z/3Z) = 0 Pros No extra dummy coil needed. No routing required High impedance of the "dummy" HB compared with the single coil. Less signal loss when both are combined in parallel. The parallel combination of single coil and "dummy" causes the resonance frequence to go up. Cons A stock strat switch won't do the job. Does the new combination sound like a single coil or as an oddball combination instead? Cheers Paul |
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Post by JohnH on Dec 19, 2015 14:28:52 GMT -5
Hello guys, I have been reading this topic, rabidgerry part in particular lately and got me thinking. Perhaps my idea is flawed. Or it has already been considered, tested and rejected for whatever reason. Please let me know what you think of it. How would the the humbucker itself perform as a (quasi) dummy coil? It seems to me that in a HSS configuration the HB with its coils in series and wired out of phase (for guitar sound) could function as a dummy coil in combination with the single coils. (Scientific prove/ Rough calculation/ wishful thinking : Assume Impedance single coil=1Z, Impedance humbucker=2Z, Hum signal voltage single coil=1V, Hum signal voltage humbucker coil=-2V Resulting noise voltage= (1V x 2Z/3Z) + (-2V x 1Z/3Z) = 0 Pros No extra dummy coil needed. No routing required High impedance of the "dummy" HB compared with the single coil. Less signal loss when both are combined in parallel. The parallel combination of single coil and "dummy" causes the resonance frequence to go up. Cons A stock strat switch won't do the job. Does the new combination sound like a single coil or as an oddball combination instead? Cheers Paul
Amazingly enough, you are absolutely right!
My first guitar which I got when I was 18, a rather quirky Shergold Masquerader, has that feature built in stock. It wasn't promoted as such, but it was an 'Easter Egg' there to be found in certain combinations.
It has two humbuckers, with a three way switch as usual, plus each pickup has a three way to select humbucker, coils in series out of phase (SOOP), and single coil. The SOOP sounds on their own are thin and noisy (but better on this guitar than others I've since tried it on), and the single coil sounds hum as usual, but in combination, the hum goes away and it is a silent as full humbucker. The tone is dominated by the single coil, but it is a tad thinner.
Here is a page with sound samples for the Shergold. Compare 'Neck pickup single coil', with 'Bridge pickup phased with neck single coil'
Shergold soundcheck
The math is interesting, 2x 'anti-hum' is being provided by a SOOP pickup, of 2x impedance, to combine with a 1x single, so it all balances out in an overall parallel combo. It leads to a conclusion that such parallel combos can to some extent, balance themselves for hum even with different coils, as here, two coils are cancelling with one. By the same logic, two similar coils in a Strat, with one with extra winds, can still balance hum. the extra impedance of one is compensated by the extra hum it picks up. I think this holds for coils wound with similar geometry and wire, and probably drifts away a bit with coils of very different configurations.
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Post by sumgai on Dec 19, 2015 15:19:07 GMT -5
pbp, Unless I miss my guess, a dummy coil is defined as a coil without any sensing magnets. In your intended application, there would indeed be a set of magnets present, and they would be located directly under the strings. Hence, if that pickup is hooked into the guitar's output in any manner, then it will affect the overall tonality, not just the hum. Besides, why are you trying to reduce the hum of a... humbucker?  If it's not doing the job as designed, then shouldn't you be considering replacing it/them? sumgai |
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Post by perfboardpatcher on Dec 20, 2015 5:58:50 GMT -5
+JohnH
Thanks for the shergold link. I knew it just had to exist! The sound is indeed a tad thinner. The signal level of the SOOP humbucker on its own is higher than I expected. Perhaps because of signal compression?
That is good news. This could be an alternative to the dummy method.
+sumgai
You're right, if we've got the terminology right it's way easier to understand.
I would like to introduce a new term for the SOOP humbucker, namely humcatching. (This could all be avoided if the thing wasn't called humbucker but double coil or twin coil instead.)
humbucker: normal application, the humbucker bucks the hum, full sound, little hum.
humcatching: compared to the humbucker the wires of one of the coils are swapped. Thin sound (therefore no dummy) and all the hum you can get.
Humcatching can be normal or reverse wired depending on from which coil the wires are swapped.
I would use humcatching not on its own but only in combination with a single coil to cancel out the hum.
So in case of an humfree as can be HSS configuration (rabidgerry):
Bridge HB
Mid SC RWRP
Neck SC
A super switch should give the following combinations:
1 = humbucker normal
2 = split humbucker || Mid SC RWRP
3 = Mid SC RWRP || humcatching Normal Wired
4 = Mid SC RWRP || Neck SC
5 = Neck SC || humcatching Reverse Wired
Technically there are 2 different sounds available for the humcatching+SC combinations, namely if you reverse the magnet of the humbucker or rotate the humbucker 180 degrees. It will mess up combination #2 but that's a different story.
Paul
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Post by sumgai on Dec 21, 2015 3:01:49 GMT -5
Paul, Your "enhanced" terminology isn't necessarily bad, but I think that most folks would rather see something like "hum-anti-bucking". You can "catch" a lot of things, but in doing so, you aren't usually "bucking" some opposite thing - the reference just isn't immediately clear, IMO. But getting past all that, we still have the issue of your "hum-anti-bucker" sitting under the strings. That right there goes against the grain of what we call a dummy coil - it's not a dummy if it's contributing to the overall tonal output of the guitar. I'm sure there's a better term for your intentions, but right about now my CRS has kicked in bigtime, so I'll have to defer to someone else busting loose with that one.  As to balancing one pickup against another (or more than one, on either end), that's always a fun project. Do keep us posted on what you figure out. HTH sumgai |
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Post by perfboardpatcher on Dec 21, 2015 13:36:21 GMT -5
Your "enhanced" terminology isn't necessarily bad, but I think that most folks would rather see something like "hum-anti-bucking". You can "catch" a lot of things, but in doing so, you aren't usually "bucking" some opposite thing - the reference just isn't immediately clear, IMO. Slowly but surely with a little bit of good will we will get there...  But getting past all that, we still have the issue of your "hum-anti-bucker" sitting under the strings. That right there goes against the grain of what we call a dummy coil - it's not a dummy if it's contributing to the overall tonal output of the guitar. I'm sure there's a better term for your intentions, but right about now my CRS has kicked in bigtime, so I'll have to defer to someone else busting loose with that one. As to balancing one pickup against another (or more than one, on either end), that's always a fun project. Do keep us posted on what you figure out. Shall we let the Shergold sound clips do the talking and leave it to the folks over here to decide whether it is a desirable sound or not? Besides, a serial dummy coil affects the sound as well. The peak frequency is transposed down, you're losing highs. Can be a bad thing. If someone would like to post a schematic with the 5 combinations of my previous post, be my guest! I have to search around a bit for a linux application that can do the job. Cheers, Paul |
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Post by JohnH on Dec 21, 2015 14:31:15 GMT -5
This is a good chance to rev up GuitarFreak6, to see if it can analyse this series/parallel out of phase combo:  These are frequency plots showing envelopes of the various string harmonics, taking into account coil positions and phase. There is a neck single coil, based on a Fender Texas Special, and bridge humbucker (8.4k) with coils in series out of phase (very thin sound - no bass), and the mix of both as discussed on this thread. You can see the signal somewhat like the single coil, a few db down in the low frequencies, and a bit less reduced in the highs, accounting for the relative thinness of the tone compared to the single coil. |
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Post by sumgai on Dec 22, 2015 3:55:43 GMT -5
{tl;dr version - skip to the Summary, if you wish} Paul, Well, you said it yourself: Shall we let the Shergold sound clips do the talking and leave it to the folks over here to decide whether it is a desirable sound or not? (emphasis mine) This is getting to be like a one-track recording: By definition, a dummy coil does not contribute materially to the guitar's output sound, or tone (or Mojo). A look at John's chart above will confirm the fact that a pickup sitting under the strings will affect the tone of another pickup, thus rendering it not a dummy. What you are contemplating has been done in many ways, and has more than one name, depending one which website you're reading. But the basic fact remains, a true dummy coil should be mute, insofar as your guitar's tonal output is concerned. Now we're speaking about electrical effects. To put this all in perspective... A dummy coil is an inductor, and as such it tends to reduce the level of higher frequencies. That said, a dummy coil can be coupled with another pickup (or more than one) in either parallel or series. The resulting total inductance can be found with the same formula as used for parallel or series resistors. But in our case, we want to consider the affect of a flat, non-varying, inductance - regardless of a series or parallel connection. In essence, such a component is exactly like a tone control - it does not notice anything like harmonics, nor more importantly, their interaction with one another. John's chart above confirms this, in a way. Where you see two pickups interacting, and thus changing harmonic and nodal relations, an inductor won't do that (neither will a capacitor, for that matter). The chart is showing a pair of pups that are both under the strings. John has already published charts of how a dummy coil reduces hum, yet does not materially affect the tone of a pickup, except for that added inductance. Said added inductance usually lowers the peak response of the pickup, but that's not always the case... and the exceptions don't matter for purposes of our discussion. What's important is that if a coil is adding to/changing the overall tonality, then it's not a dummy coil, end of story. SummaryThe foregoing was an attempt to keep the definition of "dummy coil" intact. People who search the innerwebs arrive here in The NutzHouse looking for information, and I don't like having to answer questions of a perplexed nature when the cause could've been nipped in the bud, to wit: A dummy coil does not noticably alter the tone of a pickup, except when considering that the added inductance may alter the peak resonant frequency... something that is usually not a big deal. HTH sumgai |
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Post by perfboardpatcher on Dec 22, 2015 13:39:23 GMT -5
{tl;dr version - skip to the Summary, if you wish} SummaryThe foregoing was an attempt to keep the definition of "dummy coil" intact. People who search the innerwebs arrive here in The NutzHouse looking for information, and I don't like having to answer questions of a perplexed nature when the cause could've been nipped in the bud, to wit: A dummy coil does not noticably alter the tone of a pickup, except when considering that the added inductance may alter the peak resonant frequency... something that is usually not a big deal. sumgai, I don't think we have a different opinion on what a dummy coil is. I don't see the purpose of this discussion if there is no concrete proposal from your side. Do you have a better topic title in mind? |
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Post by JohnH on Dec 22, 2015 14:30:49 GMT -5
In my head I think of these issues as involving the cancellation of 'hum' with 'anti-hum' to achieve 'hum cancellation' in coil combinations. And I think we all agree that a 'dummy coil' is really just one that has no tonal input.
As two coils from a humbucker get closer together, they approach a null output for the lower frequencies, so can act a bit like a dummy coil when combined with another.
There are quite a few of these hum-cancelling 3-coil series/parallel combos. Not all need out of phase connections, such as on a Strat, (BxN)+M is humcancelling, and sounds close to just M
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Post by perfboardpatcher on Dec 23, 2015 10:00:01 GMT -5
In my head I think of these issues as involving the cancellation of 'hum' with 'anti-hum' to achieve 'hum cancellation' in coil combinations. And I think we all agree that a 'dummy coil' is really just one that has no tonal input. As two coils from a humbucker get closer together, they approach a null output for the lower frequencies, so can act a bit like a dummy coil when combined with another. There are quite a few of these hum-cancelling 3-coil series/parallel combos. Not all need out of phase connections, such as on a Strat, (BxN)+M is humcancelling, and sounds close to just M If the way to move forward is to create a topic for hum-cancelling 3-coil series/parallel combos I have no objections. As far as I'm concerned the moderators can extract the useful parts for the new topic and close this topic. No big deal. Paul |
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Post by sumgai on Dec 24, 2015 12:39:12 GMT -5
Paul, No, we don't need to "extract and move" or anything like that, this thread is just fine. And thanks for asking, but no, I don't have any better way to title this thread. I've had my say as a "purist", and if everyone else is happy, then I am too.  But John, I do have to wonder.... (BxN)+M sounds pretty close to M alone? I can't test that on my Strat without some wire-twiddling, but I'm thinking that BxN is gonna be louder by more than a small mount, at least at the low and lower-mid frequencies, no? Has anyone else here tried this, and if so, what do you think? sumgai |
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Post by reTrEaD on Dec 24, 2015 15:02:43 GMT -5
Has anyone else here tried this, and if so, what do you think? I haven't tried it but I see no reason for that to keep me from telling anyone what I think. lol Here's my SWAG* BxN should sound similar to M in terms of harmonic content. The signal (both string-sensed and hum)will be louder by more than a small amount. But that's assuming the load in both cases would be just the pots and the amp. Since the BxN is being loaded by the much lower resistance and inductance of the M, it's contribution will be attenuated by more than a small amount. The M is being loaded by a resistance and inductance (BxN) that is much higher than it's internal resistance and inductance. It will be attenuated by a small amount. My expectation is that this would not sound exactly the same as M alone but be reasonably close. Both in timbre and output level. And the level of hum would be remarkably lower. JMO. *SWAG = Scientific Wild-butt Guess |
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Post by JohnH on Dec 24, 2015 15:37:59 GMT -5
Has anyone else here tried this, and if so, what do you think? I haven't tried it but I see no reason for that to keep me from telling anyone what I think. lol Here's my SWAG* BxN should sound similar to M in terms of harmonic content. The signal (both string-sensed and hum)will be louder by more than a small amount. But that's assuming the load in both cases would be just the pots and the amp. Since the BxN is being loaded by the much lower resistance and inductance of the M, it's contribution will be attenuated by more than a small amount. The M is being loaded by a resistance and inductance (BxN) that is much higher than it's internal resistance and inductance. It will be attenuated by a small amount. My expectation is that this would not sound exactly the same as M alone but be reasonably close. Both in timbre and output level. And the level of hum would be remarkably lower. JMO. *SWAG = Scientific Wild-butt Guess
What you have to realize about all of that is, if you are going float that kind of stuff by us, then JohnH is just going to post another graph!
These are plots of some all-in-phase combinations, and I think they broadly support your SWAG.
Dark blue is M alone
Solid red is (NxB) + M
Dashed red is (N+B) x M
Green is N+B and grey is NxB
Plots are based on three identical Fender CS69's, 250k volume, 10' cord and no-load tone. The red combos are both nominally hum cancelling.
There's a few extra interesting effects creep in as coils get added. for example, a series combo of two coils (eg NxB)should be nominally 6db louder than one coil, but in practice it doesn't quite get there due to phase cancellation due to different coil positions. As a third coil is added, high-end phase effects cause more variability. Still the general shape of (NxB)+M is somewhat similar to M, with a bit more low end and more up and down variation in the highs.
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Post by sumgai on Dec 24, 2015 19:25:43 GMT -5
John,
The one thing I notice about your graph is that the BxN (and even moreso, the B+N) combos are quite a bit more "chimey". This is what I tend to notice as I listen to pickups, and why I'm concerned with the comparison of that combo as versus strictly an M alone. I can see where the graph shows a fairly equivalent tonality up to, say, 5KHz, which is well above any fundamental we're likely to hear, but as noted over the past several decades, it's really the harmonic content that makes a pickup sound either good or otherwise.
But overall, I'm willing to concede the point, there is more than a passing similarity between the two, and taken together with any hum reduction, then there's no reason not to use this combo. (Unless, that is, a given guitar-and-pickup assembly sounds just plain terrible in the first place.)
sumgai
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Post by perfboardpatcher on Dec 26, 2015 3:37:32 GMT -5
I haven't tried it but I see no reason for that to keep me from telling anyone what I think. lol Here's my SWAG* BxN should sound similar to M in terms of harmonic content. The signal (both string-sensed and hum)will be louder by more than a small amount. But that's assuming the load in both cases would be just the pots and the amp. Since the BxN is being loaded by the much lower resistance and inductance of the M, it's contribution will be attenuated by more than a small amount. The M is being loaded by a resistance and inductance (BxN) that is much higher than it's internal resistance and inductance. It will be attenuated by a small amount. My expectation is that this would not sound exactly the same as M alone but be reasonably close. Both in timbre and output level. And the level of hum would be remarkably lower. JMO. *SWAG = Scientific Wild-butt Guess
What you have to realize about all of that is, if you are going float that kind of stuff by us, then JohnH is just going to post another graph!
These are plots of some all-in-phase combinations, and I think they broadly support your SWAG.
Dark blue is M alone
Solid red is (NxB) + M
Dashed red is (N+B) x M
Green is N+B and grey is NxB
Plots are based on three identical Fender CS69's, 250k volume, 10' cord and no-load tone. The red combos are both nominally hum cancelling.
There's a few extra interesting effects creep in as coils get added. for example, a series combo of two coils (eg NxB)should be nominally 6db louder than one coil, but in practice it doesn't quite get there due to phase cancellation due to different coil positions. As a third coil is added, high-end phase effects cause more variability. Still the general shape of (NxB)+M is somewhat similar to M, with a bit more low end and more up and down variation in the highs.
Thanks JohnH, I think I understand. With reTrEaD (loading) and sumgai's (pureness of tone) remarks in mind, how do the graphs change when the various pickup combinations are loaded with the tone cap? Now you've broadened my horizon guys I'm wondering, could (B+M)xN serve as a hum-canceling substitute for N? B has to be reversed in phase. I hope I got it right, + for parallel, x for series. The superswitch doesn't like HB SOOP combinations much, but HB series to POOP seems feasible. Paul |
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Post by reTrEaD on Dec 26, 2015 13:16:46 GMT -5
If it looks like a duck, swims like a duck, and ...What you have to realize about all of that is, if you are going float that kind of stuff by us, then JohnH is just going to post another graph! Thank you so much for posting that graph, John. I think the operative word in your assessment of my SWAG is 'broadly'. My read on that solid read line [(NxB) + M] is that it will quack HARD. A wonderful thing, to my way of thinking, but quite different than M alone. The gray (NxB) was consistent with my expectations. Only mild notches. But I was floored by the notchiness of the combination with M. Would it be too much to ask for another graph? This time perhaps, B+M (my favorite Strat sound), M+N, and (NxB)+M ?
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Post by reTrEaD on Dec 26, 2015 13:19:32 GMT -5
I hope I got it right, + for parallel, x for series. Yes Paul, that's the standard convention we use. |
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Post by JohnH on Dec 26, 2015 15:19:19 GMT -5
If it looks like a duck, swims like a duck, and ...What you have to realize about all of that is, if you are going float that kind of stuff by us, then JohnH is just going to post another graph! Thank you so much for posting that graph, John. I think the operative word in your assessment of my SWAG is 'broadly'. My read on that solid read line [(NxB) + M] is that it will quack HARD. A wonderful thing, to my way of thinking, but quite different than M alone. The gray (NxB) was consistent with my expectations. Only mild notches. But I was floored by the notchiness of the combination with M. Would it be too much to ask for another graph? This time perhaps, B+M (my favorite Strat sound), M+N, and (NxB)+M ? Here they are, is in 1db increments:  These and pevious plots on this thread are envelopes of all tones that can exist in each combo, based on pickups and fretting position, it can also be interesting to see just the harmonics of one individual plucked note. This is the 2nd string, plucked at the 2nd, 3rd and 4th fret, in order to get the three traces seperated.  The analysis has a resolution of one semitone, and harmonics are plotted to the nearest semitone. You can see about 8 or 9 harmonics of each combination, then they get harder to see although they go up to 30 harmonics of each. |
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Post by reTrEaD on Dec 26, 2015 20:20:33 GMT -5
With reTrEaD (loading) and sumgai's (pureness of tone) remarks in mind, how do the graphs change when the various pickup combinations are loaded with the tone cap? Hi Paul, It seems like your questions got lost in the sauce when I diverted attention to my own request. As you turn your tone control down, the tone cap plays a larger part in the equation and 'selectively' attenuates the harmonics. Higher frequencies = more attenuation. So basically the graphs will roll off toward the right. In general, parallel pickup combinations see less attenuation of high frequencies via the tone cap than a single pickup. Series combinations see more attenuation. Now you've broadened my horizon guys I'm wondering, could (B+M)xN serve as a hum-canceling substitute for N? B has to be reversed in phase. Interesting... It seems like that would be reasonably effective in hum-canceling. And since the (M + OutOfPhaseB) nets us half the resistance and inductance of a single coil pickup, putting that in series with the Neck won't lead to as much tone dulling as we would see with a normal dummy coil in series. The only issue that jumps out right now would be the partial cancellation of the M and B signals. The fundamentals should cancel quite well, but some of the harmonics won't. Probably see some peaks and notches in the result when combined in series with the neck. Not necessarily a bad thing. Just not exactly the same as N alone. |
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Post by reTrEaD on Dec 26, 2015 20:38:51 GMT -5
John, you are a gem. Those graphs tend to confirm my earlier supposition. This duck might be on steroids. I'm intrigued by the severity of the notches. This looks promising. |
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Post by JohnH on Dec 27, 2015 2:37:32 GMT -5
With reTrEaD (loading) and sumgai's (pureness of tone) remarks in mind, how do the graphs change when the various pickup combinations are loaded with the tone cap? Hi Paul, It seems like your questions got lost in the sauce when I diverted attention to my own request. As you turn your tone control down, the tone cap plays a larger part in the equation and 'selectively' attenuates the harmonics. Higher frequencies = more attenuation. So basically the graphs will roll off toward the right. In general, parallel pickup combinations see less attenuation of high frequencies via the tone cap than a single pickup. Series combinations see more attenuation. Now you've broadened my horizon guys I'm wondering, could (B+M)xN serve as a hum-canceling substitute for N? B has to be reversed in phase. Interesting... It seems like that would be reasonably effective in hum-canceling. And since the (M + OutOfPhaseB) nets us half the resistance and inductance of a single coil pickup, putting that in series with the Neck won't lead to as much tone dulling as we would see with a normal dummy coil in series. The only issue that jumps out right now would be the partial cancellation of the M and B signals. The fundamentals should cancel quite well, but some of the harmonics won't. Probably see some peaks and notches in the result when combined in series with the neck. Not necessarily a bad thing. Just not exactly the same as N alone.
I didn't mean to ignore, but family lunch intervened...
Here is N compared to two hum-cancelling alternates, each using B reversed in phase combined with M to provide anti-hum:
Note: It might be a good idea to run by you guys the way I am modelling these combined series/parallel combos. GuitarFreak is currently only set up to do pure series or pure parallel combos. So what I am doing is a work-around. To do combos of the form (axb)+c, I am modelling a+b+c, but with values for a and b adjusted with a factor of x4 on L and R, x1/4 on C and +6.03db on output. I believe this provides the correct relative signal levels from each coil and correct overall impedances for what we are modelling.
Combos in the form (a+b)xc and modelling as axbxc, with opposite corrections, ie x1/4, x4 and -6.03db.
Also, I am very close to posting a new GuitarFreak version, 6.2. This thread has been a very useful test case for it.
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Post by perfboardpatcher on Dec 27, 2015 7:49:02 GMT -5
I wanted to present the forum the following electronic schematic. It offers hum-canceling alternatives for both of the single coil only selections. Please check for errors.  Paul |
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Post by perfboardpatcher on Jan 1, 2016 9:44:49 GMT -5
With reTrEaD (loading) and sumgai's (pureness of tone) remarks in mind, how do the graphs change when the various pickup combinations are loaded with the tone cap? Hi Paul, It seems like your questions got lost in the sauce when I diverted attention to my own request. As you turn your tone control down, the tone cap plays a larger part in the equation and 'selectively' attenuates the harmonics. Higher frequencies = more attenuation. So basically the graphs will roll off toward the right. In general, parallel pickup combinations see less attenuation of high frequencies via the tone cap than a single pickup. Series combinations see more attenuation. Now you've broadened my horizon guys I'm wondering, could (B+M)xN serve as a hum-canceling substitute for N? B has to be reversed in phase. Interesting... It seems like that would be reasonably effective in hum-canceling. And since the (M + OutOfPhaseB) nets us half the resistance and inductance of a single coil pickup, putting that in series with the Neck won't lead to as much tone dulling as we would see with a normal dummy coil in series. The only issue that jumps out right now would be the partial cancellation of the M and B signals. The fundamentals should cancel quite well, but some of the harmonics won't. Probably see some peaks and notches in the result when combined in series with the neck. Not necessarily a bad thing. Just not exactly the same as N alone. Indeed, if we consider the electrical properties of the combination of coils we could indeed come up with a single L for the 3 coil combination to calculate the resonance peak. But take for instance (N * B) + M + C (= tone cap). Then how much do both sections (N * B) and M contribute to the voltage upswing at the resonance peak? If the tone cap changes the ratio between the 2 sections it could affect the tone. The other type of loading - with a low resistance - I only see happening in case of having a fuzz box placed right after the guitar. In such case the frequency range doesn't seem the most important but more whether the hum-canceling effect remains intact. Under these circumstances one prefers a hum-canceling over a true single coil sound option. I didn't mean to ignore, but family lunch intervened... Here is N compared to two hum-cancelling alternates, each using B reversed in phase combined with M to provide anti-hum: In my opinion (-B + M) x N looks more similar to N than (-B x M) + N . Could be that the tonal output of the humbucker compensates for the lower resonance peak of this coil combination. |
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Post by perfboardpatcher on Jan 2, 2016 11:52:25 GMT -5
I was looking for some more hum-canceling 3-coil combinations inside just for fun. Only a hardware update required for one of the options (f): flip toggle switch 2p2t becomes 3p2t. This allows positions #3 & #5 still to be A/B-tested between normal and 3-2-3-2-3. Positions #2 & #4 don't seem to provide hum-canceling alternatives. With the modified circuit there are 2 sounds available for position 1, humbucker series and one of the 3-coil combinations.  Perhaps a silly question, but is there a preferred coil combination for splitted humbucker in parallel with the mid single coil? For split humbucker on its own I prefer the humbucker coil farthest away from the bridge but I'm not sure if it's the right candidate to be combined with M (position #2). Paul |
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Post by ashcatlt on Jan 2, 2016 13:54:12 GMT -5
But take for instance (N * B) + M + C (= tone cap). Then how much do both sections (N * B) and M contribute to the voltage upswing at the resonance peak? If the tone cap changes the ratio between the 2 sections it could affect the tone. Resonance depends on the relationship between the L and the C, but... The tone cap itself doesn't have a whole lot of effect on the tone when the pot is all the way up. The pot's resistance value actually has more impact at that point. The cable capacitance (against total pickup inductance) is what is responsible for the resonant peak there. |
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Post by perfboardpatcher on Jan 4, 2016 13:40:37 GMT -5
But take for instance (N * B) + M + C (= tone cap). Then how much do both sections (N * B) and M contribute to the voltage upswing at the resonance peak? If the tone cap changes the ratio between the 2 sections it could affect the tone. Resonance depends on the relationship between the L and the C, but... The tone cap itself doesn't have a whole lot of effect on the tone when the pot is all the way up. The pot's resistance value actually has more impact at that point. The cable capacitance (against total pickup inductance) is what is responsible for the resonant peak there. I would have agreed with you if I hadn't backed down my tone control. C_tonecap * R_tonepot becomes C_tonecap. I was just thinking along with ReTrEaD's argumentation. He and some other guy left the table before I could serve the main dish. Not so much I can do about, can I? |
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Post by sumgai on Jan 5, 2016 12:17:32 GMT -5
.... and some other guy left the table before I could serve the main dish. Well, that's not quite true... I believe I'd cleaned my plate awhile ago, so I put my napkin down and went over to the buffet line, checking out some of the dessert dishes. But I haven't left the building! |
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Post by perfboardpatcher on Jan 5, 2016 13:30:52 GMT -5
.... and some other guy left the table before I could serve the main dish. Well, that's not quite true... I believe I'd cleaned my plate awhile ago, so I put my napkin down and went over to the buffet line, checking out some of the dessert dishes. But I haven't left the building! Okay then, butI bet I can produce schematics faster than you can verify them I figured out how to do a schematic with the humbucker SOOP, which I renamed into humbucker anti-serial. Giving names is not my forte. Paul  |
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Post by Yogi B on Feb 2, 2016 15:02:14 GMT -5
Note: It might be a good idea to run by you guys the way I am modelling these combined series/parallel combos. GuitarFreak is currently only set up to do pure series or pure parallel combos. So what I am doing is a work-around. To do combos of the form (axb)+c, I am modelling a+b+c, but with values for a and b adjusted with a factor of x4 on L and R, x1/4 on C and +6.03db on output. I believe this provides the correct relative signal levels from each coil and correct overall impedance for what we are modelling. Combos in the form (a+b)xc and modelling as axbxc, with opposite corrections, ie x1/4, x4 and -6.03db. Well that sounds right and looks about right with respect to what I get for the neck alone, but I'm clearly doing something different as I don't have the same 4dB/octave-ish roll-off starting at the low-mids. For instance I'm only modeling the open A string, I don't know about you, but I find it gets a bit to hectic when including all the strings Since as far as I'm aware LTspice doesn't have a built-in way to do curve smoothing, thus way I'm doing it is a bit of a hack, I'll start with my un-smoothed graph: In case the key is too small Red -- neck alone Orange -- essentially parallel combination, N + (-B x M) Yellow -- essentially series combination, N x (-B + M)  Also since I'm not sure how you are doing the smoothing I've used two methods, averaging and maximizing both over a range of plus or minus a quarter of an octave (I'd say you appear to be doing it by maximizing, is there a technical reason for this?) Averaged:  Maximized: 
Also since this is a topic about hum-cancellation with an odd a non-even number of coils, something I myself have been meaning to bring up for a while. Namely because I've been trying to work out a method of calculating the total number of hum-cancelling series/parallel combinations for an arbitrary number of similar pickups, or even what those combinations actually are. It is possible by brute force, that is taking a all the possible combinations and narrowing it down by calculating the hum output case by case, but as you can imagine that's quite an intensive process as the numbers quickly get pretty big. Surely there must be a better way? |
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If it's not doing the job as designed, then shouldn't you be considering replacing it/them?
