
Post by ChrisK on Apr 11, 2008 18:27:27 GMT 5
Taken in the full context of ALL possible combinations of 2 coils sans OFF and PHASE, there are 4 variants. Taken in the full context of ALL possible combinations of 3 coils sans OFF and PHASE, there are 17 variants. Taken in the full context of ALL possible combinations of 4 coils sans OFF and PHASE, there are 97 variants.


col
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Post by col on Apr 17, 2012 22:24:09 GMT 5
Hi Chris,
Skimming over your list of possible 4coil arrangements, I think you missed 3. I do not fully follow your table (a legend would help), but there is a fourcoil arrangement, and its three permutations missing from your list.
..^ .__ ... 1...2 ___ .__ ... 3...4 ___ .. ..G
..^ .__ ... 1...3 ___ .__ ... 2...4 ___ .. ..G
..^ .__ ... 1...4 ___ .__ ... 3...2 ___ .. ..G
Col.



Post by sbgodofmetal on Apr 17, 2012 23:24:55 GMT 5
Welcome to the nutz house. Were truly sorry to say but chrisk is no longer with us anymore. He has left us with many great articles concepts and ideas many with charts and diagrams. and a few schematics here and there. But feel free to ask any of us about his works a lot of members have been here long enough to explain anything of his to you. R.I.P. Chrisk.



Post by newey on Apr 18, 2012 3:58:17 GMT 5
col Hello and Welcome to Gnutz2! Somewhere, ChrisK is having a chuckle. This is a logic puzzle, and I don't fully understand his notation either. But I'll guarantee you, the failure to include a key was a purposeful omission. He was challenging us to figure it out for ourselves, hoping to get us to "see" the logical sequence. ChrisK never handed anything out on a silver platter, as he felt no one would learn anything that way. "Teach a man to fish", as the old saw goes that was one of his favorites. If I can decipher your notation, col, you are suggesting that Chris forgot the arrangement of 4 coils whereby two series pairs are joined in parallel and the permutations of that arrangement, i.e., (1 X 2) + (3 X 4), (1 X 3) + (2 X 4) and (1 X 4) + (2 X 3). Look in the second column, 4th diagram down, and I think you'll find that Chris has not, in fact, omitted these possibilities . . . BTW, I have built a guitar that realizes all those series pairs, joined in parallel the "4Caster": It does not, however, do all 4 coils in series, nor does it do 3 in series, in parallel with the fourth. The structure is based on pairs of coils. Of course, two pairs of coils in series, which are then joined in parallel represents the standard wiring for most two HB guitars such as SGs and LPs, if we further assume that the pairs of coils are close enough together to "cohabit" one pickup frame.



Post by ashcatlt on Apr 18, 2012 10:02:10 GMT 5
col's diagram looks to me like parallel pairs in series with one another  (1+2)x(3+4), etc.
I'm not actually seeing that represented in chrisk's table. I want to say that this is because it's mathematically the same as the parallel combination of series pairs, but I can't make that work unless all four coils are the same.
[using our standard notation of + for parallel and x for series, don't try to just do normal math here.] (1+1)x(1+1)=1=(1x1)+(1x1) but (1+2)x(3+4)=(50/21)!=(1x2)+(3x4)=(21/10)
But maybe I'm missing something...



Post by reTrEaD on Apr 18, 2012 12:25:13 GMT 5
I want to say that this is because it's mathematically the same as the parallel combination of series pairs, but I can't make that work unless all four coils are the same. Right. Let's compare these two similar configurations... ..^ .__ ... 1...3 ___ .__ ... 2...4 ___ .. ..G
..^ .__ ... 1...3 ... ... 2...4 ___ .. ..G
Let's arbitrarily assign values for the resistance (or inductance) of each coil as 1, 2, 3, and 4, respectively. Then solve for the total in each circuit. In the first case we would have: (1//3) + (2//4) = (3/4) + (8/6) = 0.75 + 1.33 = 2.08 (product over sum for parallel) In the second case we would have: (1+2) // (3+4) = 3//7 = 2.1 Similar, but not exactly the same. If the coils are not identical, there will be a slight difference in the total resistance (or inductance). Is that the end of the story? Maybe not... Even with identical coils, each coil is sensing a different region of the string. So the amplitude and ratio of fundamental to various harmonics will be quite different on each coil. And we are combining them in a slightly different way. So I would expect a small disparity of tone between the two configurations. Imagine two identical HBs that have traditional (internal) series connections placed the bridge and neck positions, in parallel with each other. Now connect the two series links together. Will this sound different than when the series links were not joined together? I think so. Will the difference amount to much? Probably not.



Post by sumgai on Apr 18, 2012 12:39:39 GMT 5
col, Nice eye, almost a good catch. But, as usual, the devil is in the details. It so happens that various members of this board have had this discussion, often, in the dim and distant past. Here's the nutshell breakdown: Without getting into any kind of math, all we need is simple arithmetic for this excercise. Look at the numbers in the small boxes below the count (for each possibility)  those represent the impedance ratios for a given combo, as compared to one single pickup. (Assuming that all four coils are identical.) As a starting point, it's interesting to note that the "standard" combo of two coils in series (one standard pup) in parallel with another such also comes out to "1". Now, if I can guide your attention to the lowest row, second column, you'll find this exact combo, with the "1" as I've described. Look at all the other combos, you'll not find another ratio of "1". (I'm describing combinations here, not single pups.) Let us now turn to your diagrams.... Your assignment is to determine what the ratio of inductance will be for each of the three combos, as relative to the standard "1". For extra credit, explain how they will deliver a different tonality to the output, and thence on to the amplifer/speaker. This is exactly what newey was speaking to, the fact that Chris never gave anything away without a fight. Well, he did once give some free Unobtanium to JohnH, but that's a story for another day! ;D HTH sumgai



Post by ashcatlt on Apr 18, 2012 14:07:47 GMT 5
Umm...sg? retread and I have covered that. If all the coils are the same then all of these combos come out the same. But that's rarely the case. More often (ie  typical HH configs) we'll have two pairs of coils which are internally close enough to identical but signicantly different between the pairs. Worse, consider newey's 4caster, where (I think) all four coils are different.
There are proofs above.


col
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Post by col on Apr 18, 2012 17:39:17 GMT 5
Welcome to the nutz house. Were truly sorry to say but chrisk is no longer with us anymore. He has left us with many great articles concepts and ideas many with charts and diagrams. and a few schematics here and there. But feel free to ask any of us about his works a lot of members have been here long enough to explain anything of his to you. R.I.P. Chrisk. Hello sbgodofmetal, I am sorry to learn that ChrisK passed away. I see that he contributed/compiled a hellofalot of data  it seems he was an interesting guy.


col
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Post by col on Apr 18, 2012 18:02:34 GMT 5
Hi,
I've read the replies with interest.
I think that there will be little difference between many of the possible configurations already outlined by Chris. Since this was supposed to be an exhaustive list, I just thought I'd point the missing configurations.
I am not an electronics guy, but I understand a few basics. I get the gist about there being little difference between the two circuits if the pickups are (near) identical (the circuit pointed out by me; and a standard inseries pair of coils, and the two pickups wired up in parallel, as is common across most HH setups with a three way switch). However, I do question if 'there is little difference in the two examples', for this reason: even if the pickups were theoretically identical, the signal generated by each pickup will be different (since they each sense a different part of the guitar string, or at a different distance from the string). Wouldn't these different signals combine quite differently in the two given arrangements? Just a thought.
Thanks for the replies and detailed information about how to make the calculations, and how to read Chris's tables.


col
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Post by col on Apr 18, 2012 18:14:16 GMT 5
Is that the end of the story? Maybe not... Even with identical coils, each coil is sensing a different region of the string. So the amplitude and ratio of fundamental to various harmonics will be quite different on each coil. And we are combining them in a slightly different way. So I would expect a small disparity of tone between the two configurations. Imagine two identical HBs that have traditional (internal) series connections placed the bridge and neck positions, in parallel with each other. Now connect the two series links together. Will this sound different than when the series links were not joined together? I think so. Will the difference amount to much? Probably not. Sorry, I see that my point was already covered by reTrEaD.



Post by newey on Apr 18, 2012 18:44:21 GMT 5
OK, we're debating apples and oranges here.
ChrisK's original post was detailing all possible combinations of 2, 3 and 4 coils. Certainly, different positions along the strings and differences in the coils will allow for different tones but Chris' post doesn't have anything to say about tones, only about combinations of coils. He expressly omits "all off" and phasing from consideration, meaning we're talking about explicating all possible series and parallel variants.
I did misread col's diagrams. So we're clear here, we're talking about parallel pairs of coils which are then joined in series I had it the other way around.
But I still think Chris didn't omit these they're included as a subset of the series pairs. He indicated that, when we're considering combinations involving all 4 coils, that these number 49 total. If you look at the diagrams he has which show all four coils in various configurations each one has a red number in the second box shown next to each 4coil diagram. Add all those numbers together, and you indeed get 49 combos.
Mathematically, this is an exercise in matrix algebra, permutations and combinations and that's about the point where my limited math talents ran headon into a brick wall.
But if you look at those diagrams which show some coils in series with others in parallel, I don't see how we get to 49 unless the 4 noted by col are included in one of the diagrams which indicates 12 combinations.
Anyway, I can't do the math and I haven't got time to write out 49 combos, but I'll have to do so eventually since col now has me curious!



Post by ashcatlt on Apr 18, 2012 18:55:37 GMT 5
I personally am talking only about the action of the filter created by the interaction of the resistance, inductance, and self capcitance of this set of coils.
If we start to get into the harmonic content transducer from the strings it gets out a little beyond me. I'm not sure how the different circuits change the way each individual coil contributes to the overall mix. Is the voltage calculation the same as the R calculations? I suppose some leasing with Ibm's law might explain it, but no time right now.


col
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Post by col on Apr 18, 2012 19:23:11 GMT 5
Hi,
I have a total of 52 possible arrangements with 4 pickups (not including outofphase configurations).
The below figures indicate the number of possible arrangements as they relate to the positions in Chris's second table. I created these figures independent of Chris. The three arrangements I described are in addition to the below.
xx xx xx 01 xx xx 04 xx xx 06 12 04 01 03 06 12
Chris's table indicates three possible arrangements for the "series pairs"  this is correct. This does not include the three possible arrangements for parallel pair of coils, then placed in series, as I described. My and Chris's numbers tally, except the for the missing arrangement I described in my opening post.



Post by reTrEaD on Apr 18, 2012 21:41:01 GMT 5
Is the voltage calculation the same as the R calculations? Good question. I suppose I should plug in some values for disparities in E while holding series R the same for each coil, then compare with and without the series links being bridged. But I'm feeling lazy atm.



Post by sumgai on Apr 19, 2012 21:25:19 GMT 5
ash, As noted, we're talking idealized here, nothing real world about the tonality... except that you then went on to ponder the potential differences in potential (sorry, couldn't help that ) for having each coil in a structure located in a different position along the string. As we concluded many years ago, the overall difference is not noticible to the ear, and likely not to any kind of spectrum analyzer you and I are likely to get our hands on. IOW, the coil sensing the signal at X inches along the string will sense the same amount of energy, and convert it to the same amount of voltage/current, regardless of which way it's connected to the other coils, be it parallel then series, or the other way around. But I do stress, we're speaking of idealized exactitude in our theoretical coils and pickups here, not what we'd ordinarily find in the real world.
All, I do take it that Chris meant to display all possible combinations here, not just those that are unique in some way. For that reason, I must surmise that he did indeed "miss" some of them. One can only wonder now at his reasoning for this omission. But then again, this is how Legends are born, right? ;D +1 to col for making everyone shake their heads in wonder and disbelief at how we could've missed that for so long.... sumgai



Post by reTrEaD on Apr 19, 2012 23:38:26 GMT 5
I do take it that Chris meant to display all possible combinations here, not just those that are unique in some way. For that reason, I must surmise that he did indeed "miss" some of them. One can only wonder now at his reasoning for this omission. It's possible that it was not an oversight, but was an intentional omission. DC loop analysis suggests my earlier speculation was WRONG, regarding a difference between parallel pairs in series and series pairs in parallel, based on identical coils and different harmonic structure at each coil. UNLIKE the case where the resistance/inductance is different for each coil, having a different signal on each coil will not produce a disparity in output when the series links are bridged. Even though you can have different voltages at the two "series link" nodes, the output will NOT change when the series links are tied together. I'll stop short of saying there is no difference between the two, allowing for the possibility that there is something that has been overlooked. But I suspect Chris may have considered this to be a redundancy and intentionally omitted the series combination of parallel pairs.


col
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Post by col on Apr 20, 2012 0:22:30 GMT 5
From what I've read, there is some disagreement, or argument, as to whether or not there is any theoretical difference between the two circuits, assuming that that the pickups are identical, and the signal generated by the four pickups are identical. But, of course, even if the two arrangements are electronically identical, in reality the signal generated by each pickup will vary quite considerably  I can only surmise that the interplay of the four pickups in the two arrangements will also vary significantly enough to be of interest.
Maybe someone might like to test this is the real world?
What free software is available for testing out these kind of circuits?
Col.


megi
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Post by megi on Apr 20, 2012 5:12:05 GMT 5
I'm thinking it's possible that he has just listed all the types of configuration, and deliberately not shown every arrangement within each type? So for example, with one pickup in series with 2 others in parallel, there would be 3 ways of doing that, but he only shows one diagram. The numbers on the left may then fill in the details re number of ways the diagram can be realized.


col
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Post by col on Apr 20, 2012 13:22:06 GMT 5
I'm thinking it's possible that he has just listed all the types of configuration, and deliberately not shown every arrangement within each type? So for example, with one pickup in series with 2 others in parallel, there would be 3 ways of doing that, but he only shows one diagram. The numbers on the left may then fill in the details re number of ways the diagram can be realized. No, ChrisK listed all the permutations for each fourcoil configuration. Check the table in my last post; ChrisK's corresponding figures are shown in red and underscored in his diagrams/tables.

