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Post by asmith on Aug 25, 2011 7:31:30 GMT -5
Inspired by JohnH's Strat SP scheme, I thought about combining the pickup selection trickery from that - especially the 'universal phase switch,' that's a holy grail - with two of my own schemes: the Spin-a-Split / Tone control and the Variable Out-of-Phase / Tone control. Hey, the Beatles stole things too. This is the monster that emerged. Click here for an old diagram. Scroll down for more up-to-date images. I haven't grounded the pots, and I haven't added the obligatory treble bleed mod, as that's not my focus on this thread. This schematic is a WIP and obviously, I'd appreciate some checking from the board. Here are my intentions: Switches & ControlsSW1 is the Five-Way SuperSwitch. SW2 selects between pickups in Series or Parallel. The pot is the master volume. SW3 is a little more complex. When in Series mode, it switches between a fader control and a standard 'high-cut' tone control for the bassiest pickup. That's either a 'Spin-a-Split,' or a 'Broadbucker' control. In Parallel mode, it's still a fader control for the bassiest pickup, but the tone control acts as a master high-cut tone control on both pickups. If you select a Single Coil in parallel, the control switches between two different capacitors to ground, some kind of simplified mutant Varitone. SW4 switches between a tone control, and a Variable Out-of-Phase control, but using inductors instead of capacitors. It acts as either a mid-cut control, or allows only mids through for the pickup with the most treble selected to be put Out of Phase with the bassier pickup. That inductor connected to the lugs of SW4 is only used in 'Variable Out-of-Phase' mode, and I'd appreciate your thoughts about whether replacing it with a capacitor might be more useful.Possible SelectionsParallel | Series | B | B* | B+M | BxM | B+N | BxN | N+M | NxM | N | N* |
In accordance with the ideology that if you have two positions that do the same thing, you're wasting a position, those asterisks indicate adherence to that. In Series mode, those single coils are affected by the Fader / Standard Tone Control ( SW3) in a different way. In one mode, the control puts the selected single coil in variable series with an inductor to cut highs and lows. In the other, the inductor is always in full series with the pickup, and it controls a capacitor in variable parallel with that inductor. This last idea needs some more looking at, to determine how and how much the capacitor and resistor attached to the potentiometer-lugs of SW3 would affect that control. Also, an inductor can be added in series with a Single Coil already, by putting the selected pickup 'out of phase' and then adjusting the phase control. If anybody has any bright ideas about what that inductor below SW1 might be replaced with, I'd be very interested to hear.Comments invited.
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Post by newey on Aug 25, 2011 21:49:12 GMT -5
Overall, this is a real tour de force! Are you planning a build of this?
I think your best bet to determine values, cap vs. inductor, etc., would be to do some bench testing external to the guitar. Do a mock-up of that module and see what you have.
Other than that, I don't have any magic recipe, you're the guinea pig on this!
I'm not sure where to find it, but a while back we had some discussion of inductors. ChrisK mentioned that a single small transformer was essentially 2 inductors, and that one-half of a transformer could be used instead of an inductor- a cost savings. Then the idea was floated that, if the two halves of the transformer were of different inductances, one could wire an On-On-On switch between the two, so as to have 3 possible combos of inductors.
I mention that since you have multiple inductors here, might be an idea. . . .
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Post by JohnH on Aug 25, 2011 22:26:34 GMT -5
Seems like an interesting extension.
You might find this to be a good time to get your head around 5Spice, if you havnt already. It will help you get a handle on the implications of varous values and arrangements in your tone circuits. Theres no need to model the switching, just the total pickup and the tone elements. Also, no need for a deep understanding of the theory, just the ability to drag and drop and understand the representation as a schematic. John
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Post by asmith on Aug 26, 2011 3:16:21 GMT -5
Overall, this is a real tour de force! Are you planning a build of this? Yes. How soon... I do want another Strat. I also want to be financially healthy and do some travelling next year. I'm not sure where to find it, but a while back we had some discussion of inductors. ...I mention that since you have multiple inductors here, might be an idea. . . . That sounds very interesting. One of my own self-imposed conditions on this build is ' invisibility,' but I'll root out that discussion considering I'm thinking about inductors in series and parallel with other things. You might find this to be a good time to get your head around 5Spice, if you havnt already. I've got my head around drafting up circuits no problem, but once I've completed that I've no idea how to get a frequency reading. Would you care to educate the great unwashed please? Many thanks for your feedback.
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Post by JohnH on Aug 26, 2011 17:04:44 GMT -5
So do you have the program, and got it so you can draw circuits? To get the analysis, first, you have to have the following in the circuit: a signal source and a ground sysmbol (find those on the tool button with a battery symbol) and a test point TPv - to measure voltage signals at. Then, from the analyze menu, call up an 'AC' analysis, set frequency range (say 20 to 20,000hZ), and on the Graph/Table tab, set it to plot from your test point. Hit Apply/run to run the analysis. Does that get you going? after that you can play with values, sweep the parameters etc. I could write up a step by step guide to 5spice, with screen shots etc. John
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Post by asmith on Aug 29, 2011 14:24:46 GMT -5
I got the program working. Thanks for the guidance John, I really appreciate it. I changed out the inductor to be put in series with the Single Coils with a capacitor, to cut bass. In the previous diagram, I only had highs and mids affected on the Tone Controls. I also added caps in series with the inductors, to affect the mid-range of the frequency response more definitely. Here's a new diagram. That capacitor to be put in series (C5) seemed to give the best range of response at around 1pF, as I've set it in the following 5Spice mock-ups. I've amended it to 2nF - I was talking crap. This still results in not much difference in the effect between the Tone control switch ( SW3) states. Compare here and here. Bugger. Here's some data on some 5Spice readings I've done, for the Single Coils in Series settings. The two schematics are drawn out towards the top of the table, with the Frequency Readings for each control towards the bottom. Regular Tone, In Phase | Regular Tone, Out of Phase | Spin-A-Split, In Phase | Spin-A-Split, Out of Phase | | | | | | | | | | | | | | | | | | | | |
If you'd prefer to browse through the directory, find it here. To check out the old responses, with the cap at 1PF, find that directory here. As you will see from the Frequency Readings, the 'Mid-Cut' seems to work just fine, but when the switch ( SW4) is pulled, the 'Low-n-High Cut' doesn't do much. Changing the pot value up to around 2M helps the range of response, but not much. I don't want to do that anyway, as the 250K pot gives a great range of response for the 'Mid-Cut' setting. If anybody could contribute towards solving that Low-N-High-Cut problem, I'd be grateful. Of course, it goes without saying that all of this work isn't vetted yet, and may turn out to be complete toss. * EDIT: I've just noticed this Frequency Reading's underlying signal is based on the tone control being at full 'effect.' I'll get this sorted when I'm not at work. Fixed.
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Post by asmith on Sept 3, 2011 12:00:22 GMT -5
Small update regarding cap, inductor and pot values after some 5Spice testing.
In parallel, as a mid-cut, good values seems to be somewhere around 1H, 6nF, with a pot of 250k for the best sweep.
In series, as a low-and-high-cut, good values seem to be 4H to 5H, 6nF and a pot somewhere around 500k-1M.
So now it's just a design issue. The Variable Out-of-Phase pot & switch (SW4) needs an overhaul.
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Post by roadtonever on Sept 8, 2011 1:24:48 GMT -5
Just wanted to say I really like what you have going here, asmith.
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Post by asmith on Sept 8, 2011 15:07:13 GMT -5
Thank you Roady, that's very kind. I'll really like it myself as soon as I can work out a variable phase switch I like.
My values for the Mid-Cut have changed to around 3nF and 2H. For the Low-n-High Cut, the component usage is looking like it will change from attempting to use a larger inductor in series, to including a cap to ground.
As always, you heard it here first. This is A. Smith, signing off. To the pub!
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Post by asmith on Sept 12, 2011 5:57:35 GMT -5
That was a ballache. Leading to: C1: 22nF | C2: 6nF | C3: 6nF | C4: 2nF | C5: 2nF | L1: 2H | SW4: 250k I'll post some frequency readings soon. I haven't done the legwork on putting images together yet, but I have done some 5Spice testing. Everything comes up roses.
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Post by fenderbender on Sept 13, 2011 14:44:48 GMT -5
Hmmm....no humbucker variant for an LP style guitar? JK! (wondering if you are sick enough to try and tackle that) Might have to order some parts and bust out the iron again. Thanks for sharing this design.
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Post by fenderbender on Sept 23, 2011 14:57:14 GMT -5
So I started digging around for parts and found that a 2H inductor is about as common as unicorns. Mouser has a couple listed, one is many weeks out and the other is roughly the size of a smallblock Chevy. Are there other sources anyone knows about for these things?
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Post by JohnH on Sept 23, 2011 15:25:52 GMT -5
I reckon the way to persue this concept is to lay down a few $ for a multimeter that measures inductance, then raid the toy cupboard and crack open a few small wall-warts to see if their transformers have usful inductance values - I read somewhere that this may be true.
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Post by fenderbender on Nov 10, 2011 13:24:58 GMT -5
Just had another thought about this design...is it possible to adapt it to a P-90 and a humbucker while still keeping the HB traits?
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Post by JohnH on Nov 10, 2011 14:12:14 GMT -5
Just had another thought about this design...is it possible to adapt it to a P-90 and a humbucker while still keeping the HB traits? You could, its three coils and switching could be the same whether or not two of them are part of the humbucker or separate singles. The normal series-connected Hb would be the equivalent of B and M combined, with series switch pulled. The only issue with this is that the design only works with two coils at once, so you would miss out of having the full Hb combined with the P90. To include that would be a different design. J
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Post by fenderbender on Nov 10, 2011 15:36:56 GMT -5
The only issue with this is that the design only works with two coils at once, so you would miss out of having the full Hb combined with the P90. To include that would be a different design. Well that's a bummer. I'm a couple of days away from starting on a guitar I designed and thought there might be a chance for this one to work. My other plan is 1V 1T 5-way SS. Guess I'll have to look around for something on that config. Thanks, John.
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Post by JohnH on Nov 11, 2011 3:35:48 GMT -5
The only issue with this is that the design only works with two coils at once, so you would miss out of having the full Hb combined with the P90. To include that would be a different design. Well that's a bummer. I'm a couple of days away from starting on a guitar I designed and thought there might be a chance for this one to work. My other plan is 1V 1T 5-way SS. Guess I'll have to look around for something on that config. Thanks, John. But what would you actually like to have? There's always more new wiring designs waiting to be discovered! If you had a P90 and an Hb, how would you like them to be controlled or what would you like them to do? John
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Post by fenderbender on Nov 11, 2011 4:39:08 GMT -5
There's a loaded question...
Personally I like the idea of a HB at the bridge and P90 for the neck. I don't want more than two knobs if possible and the tone control can vanish for all I care. I'd prefer something that actually has useful tones throughout its range. EG: the thread I started a while back with McInturff demoing his inductor circuit. Long winded advert or not, that thing has potential. Seeing this design I wondered if it might be worth asking since it's still a three coil deal. Though, as you pointed out earlier, it gives up the HB & P90 together setting. That sort of kills it for me on that level.
Guess I still have plenty of time to ponder what can be done with it before making a commitment.
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Post by JohnH on Nov 11, 2011 5:35:21 GMT -5
Since this thread is about asmiths version, why not start a new thread, and state if you want two knobs and a toggle, or maybe a 5 way, or just two knobs? and any other wishes etc.
J
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