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Post by ashcatlt on Jan 21, 2023 17:19:33 GMT -5
This is probably even more difficult to follow than newey's, but I'm pretty sure it does the automatic coil switching that I was talking about. I went with the SD colors for the HBs (though I don't know or care which is inner or outer or slug or screw, and if that stuff matters, it might need some restacking), but decided to color the SC wires to indicate which of the HB coils they match. Since that can go one of two ways, and it kind of matters, I went and provided both diagrams. In both cases, the M always cancels with the N. The B cancels with the N unless the M is on, then it cancels with the M instead. I've omitted the V and T and jack. I don't actually advise connecting wires "in mid air" like I've drawn them. You can choose any convenient lug to make those connections. The series link for the HBs, for example, can happen at the split switch, I just didn't feel like drawing two lines for each. The direction of the switches is probably weird. Toggles can of course just be rotated in the pickguard when you install it, but for the P/P, you'll want to think about which way is actually supposed to be up. I personally feel like darn near every guitar in the world switches pickups just by connecting or disconnecting the top of the coil, leaving the ground ends always connected, so don't see a good point in trying any harder than necessary. If you really want to use those unused lugs, you certainly can disconnect the bottom of the HBs also, but the SC would need another pole since I hijacked the one for the coil selection. Hope it helps.
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Post by ashcatlt on Jan 20, 2023 17:06:06 GMT -5
The on/off part only needs one pole, but if we use a DPDT switch, we can use the other pole to determine which coil one of the HB splits to. I figure use the middle switch for this. It seems like you're more likely to use B+N or N+M, but B+M more rarely. So we'd wire it so that the N always splits to humcancel with M. When the M is off, the B splits to humcancel with N, but when the M is on, the B splits to the other coil. When all three are on, you can only have partial humcancelling no matter what anyway. I'm sure it works, and I think it makes some sense. (??)
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Post by ashcatlt on Jan 18, 2023 11:55:47 GMT -5
With a capacitor in series with one coil, the DCR is going to look infinite. When you measure the DCR of the parallel combination, you’re only actually reading the one coil. DCR measurements are basically meaningless at that point.
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Post by ashcatlt on Jan 13, 2023 22:22:00 GMT -5
Two weeks late, but what the heck.
A pot wired as a series rheostat relies on some other part of the circuit to be the "bottom resistor" in the voltage divider.
In a blend pot, that will be other other pickup, which is significantly smaller than the full value of the pot, so we get significant attenuation. In a V pot, that "bottom" value is mostly dominated by the tone pot except at pretty low frequencies where it's probably going to be the Input-Z of the first active stage in the chain (amp, pedal, whatever). This basically means the ratio can never go all the way to 0, and in fact probably won't even get close. The blend pot never really gets to 0 either, but it usually will get closer and for the full spectrum. But it kind of only needs to go down to like 1/10 so that this pickup's contribution to the mix is less than the 1db we consider to be significantly perceptible. In the (master) V pot, there is no other signal to mask it, so not going to silence matters. You'll find that with dual V guitars, you don't really have to turn the one V down very far before that pickup stops making much difference in the mix also.
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Post by ashcatlt on Jan 13, 2023 21:41:30 GMT -5
...in series the resistances simply multiply... Uhhh...wanna try that again? They add. Around here, we use * as shorthand for series connections, as opposed to + for parallel, but that is very much a GNutz specific convention and has nothing at all to do with the actual math. Ignoring certain of the esoterica such as actual coil size and parasitic capacitance (which yes will make a difference, but not enough to worry about in "back of the napkin" rough theorizing), 2 x 1H coils in series equals exactly the same 2H as 2 x 4H coils in parallel. If we're talking about just inductance, the difference we might expect to hear is a change in frequency response, and in this case there would not be expected to be any. Now, if those coils are also 2 x 1K DCR in series, that's still kind of the same 2K as 2 x 4K in parallel. If we're just talking about resistance, the difference we'd expect would be broadband level, and (all other things being equal), I'd still expect them to be about the same, at least assuming that the ultimate load is bigger enough than 2K to be mostly ignored. DCR by itself can't tell you anything about potential output, but in two coils which are otherwise the same, a higher DCR is expected to create hotter output because of Ohms Law, I think. The magnetic field creates a current flow. "The induced current depends on both the area of the coil and the change in magnetic field", nothing to do with the DCR. The voltage drop caused by that current flow is proportional to the resistance (V = IR), so bigger DCR gives bigger V for a given area of coil and magnetic field. Edit - actually that's weird and I'm not so confident in it, so let's not go there. It's more like when you put two batteries in series. If we call the bottom of one 0V, the top is (say) 9V. The top of the second is 9V above its own bottom, but if its bottom is on the top of the other, it is 18V above the first one's bottom. Or, to look at it a slightly different way, in series, both coils are pushing the same direction the same amount at the same time, so the force they exert is added together. In the parallel case, though, the two coils actually form a voltage divider. If we consider just one coil as the source, the voltage it puts out is halved (assuming the two coils are matched), if the other is the source, it is also halved. They're actually both the source, and both are halved, and those then add together, so we're back to the voltage of just one of them on its own. But remember these coils were already double what we were talking about in the series configuration. So it's kinda like 1 + 1 = 2/2 + 2/2
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Post by ashcatlt on Jan 13, 2023 17:20:21 GMT -5
Edit - Ah heck! This was in reply to unreg’s post 28-29. totally missed the second page of the thread! guitarnuts2.proboards.com/thread/10178/simulated-coil-tap?page=1&scrollTo=107285A slightly over simplified way to look at it is that a capacitor is like a resistor whose value is large for low frequencies and gets smaller at higher frequencies. A resistor in series with that makes that “resistance” look that much bigger for all frequencies. Neither (alone or together) really does anything except as a part of a voltage divider with some other component(s). A V pot usually increases series resistance while decreasing parallel resistance. How and why that matters also depends on about everything else.
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Post by ashcatlt on Dec 28, 2022 22:49:06 GMT -5
The big thing that happens when a coil is tapped is that the inductance of the pickup is reduced. This causes the cutoff frequency of the pickup’s LPF to increase. You don’t just (or even at all, really) get more of what high frequencies were there, you get higher frequencies. A cap in series can’t help with that. An inductor in parallel might.
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Post by ashcatlt on Dec 27, 2022 12:03:05 GMT -5
Alternatively you could theoretically connect the 'diodes' to the relevant reference voltage instead (and only AC couple them to ground, via a cap), but I don't recall ever seeing this done in practice. There are some schemes out there that do it. Can’t think of one off the top of my head, but I know I’ve seen it. It’s actually better to do it this way when you’re shooting for asymmetrical clipping because an asymmetrical square wave looks very much like a square wave with a DC bias. Coupling caps won’t let that stand, and will tend to float toward the actual center point.
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Post by ashcatlt on Oct 30, 2022 10:53:14 GMT -5
Any amp a 12V amp if you have an inverter. If the vehicle has an “aux hole”, you could just use an amp sim pedal. I know that’s not what you asked for, but it looks like you’ve got that under control.
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Post by ashcatlt on Sept 15, 2022 10:51:08 GMT -5
If the cap is in series with the bridge and the bridge is in series with the neck…. Master highpass, which I could see being useful. With the cap parallel to the bridge and that structure in series with the neck, it’s that broadbucker thing where you get all the treble from the neck, none from the bridge, and the bass from the series pair. I have several guitars which can do this, and I really don’t care for them either, especially when it’s the bridge that’s bypassed. Might be useful for certain specialty sounds, but it just always feels and sounds weird to me.
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Post by ashcatlt on Sept 14, 2022 11:28:51 GMT -5
If the cap is parallel to the bridge and the bridge is parallel to the neck…. It’s just a master T turned all the way down. If the cap is in series with the bridge, it’s a high pass on the bridge and kind of makes a weird mid scoop when combined with the neck. I have a couple of instruments which will do neck parallel to a strangled bridge. Can’t say I care for it very much. It gets kind of clacky and brittle without the midrange complexity that keeps me in the middle position most of the time. I’m very much wondering how we’re gonna make all this happen on a standard 5 way, but I’m sure if anybody can do it, they hang out here.
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Post by ashcatlt on Sept 4, 2022 11:39:06 GMT -5
I feel like it wants to be on the other side of the volume but after the other switching.
Edit - no I take that back. It can stay right we’re it is. Disconnect everything having to do with neck (/middle) and you have two wires in and two wires out and none of them are connected to shields until this switch tells them which.
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Post by ashcatlt on Sept 2, 2022 21:07:36 GMT -5
Well, the resistor to ground will cut all frequencies, while the cap will just cut the highs... You'd have to use a pretty darn small resistor to get much broadband attenuation, and it would probably be way too dark before that point. Remember that most of the action of the tone pot is actually just that as you turn it down, the resistance parallel to the pickups gets smaller. The cap is almost just there to stop it from going to silence when it's all the way down. Except when the resistance of the tone pot gets small so that the capacitor is more directly connected to the inductance, you start to get resonance near the cutoff frequency because of imaginary numbers and vector math and stuff.
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Post by ashcatlt on Sept 2, 2022 13:41:27 GMT -5
To be clear, I don’t really care where you collect your grounds. IF they’re all actually well bonded and conduct properly, any place in the circuit is about as good as any other (with the caveat of watching for signal grounds which become signal hots from phase switches, series connections, etc). My objection to using a pot case for that is that they are difficult to solder to and get an actual solid connection that you can trust. Why make it harder on yourself than you need to? Find a lug that’s actually meant to be soldered and do it there if at all possible.
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Post by ashcatlt on Sept 1, 2022 13:45:56 GMT -5
Get a small interface with an instrument input and a small pair of powered monitors. Use plugin amp sims.
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Post by ashcatlt on Sept 1, 2022 11:44:32 GMT -5
I can’t speak to that wiring specifically, but I don’t find it unusual or surprising that touching an ungrounded pole piece would cause some noise. As we know, a lot of the noise we get from pickups comes from us. That’s why we have a bridge ground. When you touch a pole, you’re basically focusing all that noise right into the middle of the coil where it can do the most damage. Happens on several of my guitars. The fix is to not do that.
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Post by ashcatlt on Aug 31, 2022 21:45:03 GMT -5
Ash, you have a similar configuration in a guitar? Correct? No I’m sorry. I have a “hybrid” guitar (offset body like a jag but bridge like a tele), but all the pickups are 5 wire (4+shield) HBs. I do have an LP with 2-wire covered HBs which I did not mess with converting. It doesn’t have a phase switch, but does (well, did…) do series, which sort of puts the shield connection for one pickup in the middle of things. That’s not quite the same as shield connected directly to jack tip, and might not be expected to be quite as bad. I can’t say I ever noticed any inordinate amount of noise there, but that position gives such extremely hot desired (string) signal that it’s tough to gauge. Plus I only really ever used it in the studio so don’t know what might have happened in a more questionable EM/RFI environment like a club. Then my dad decided to “restore” the wiring of the pots without actually understanding the switching, so now it don’t work right at all.
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Post by ashcatlt on Aug 31, 2022 17:54:51 GMT -5
I may not be understanding what you’re describing.
First check continuity between that bottom wire and the baseplate of the pickup. If they are connected, you’re going to have to figure out where and disconnect them. The wire which you connect to the switch lug should not connect to the baseplate (or in case of neck, the metal cover, or in general any shield). Then you need another wire from baseplate(/case/shield) to wherever you’re collecting your grounds. In a tele, that wire from the baseplate is also your whole string/bridge ground, so is pretty important. Basically, the wires from the actual coil of the pickup need to be separate from those to the body of the pickup if you ever want to elevate that bottom wire - whether for phase purposes or in a series arrangement.
Hope it helps.
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Post by ashcatlt on Aug 30, 2022 18:32:32 GMT -5
How often are you playing with feedback? I know you’re not asking me that question. LOL. But honestly I’ve never actually tried that little trick. I have a couple guitars with phase switches. Even had a Mustang in my custody recently. Just never really tried it. Mostly I think you can get the same result with about the same reliability just by moving the guitar, and probably much more reliably by actually touching the harmonic node on the string itself. frets - when you flip the phase switch, the bottom wire becomes the top wire (and vice versa). If that original bottom wire was also the shield ground for that pickup, it’s now dumping its noise onto the jack tip. We’d like those wires to be separate coming out of the pickup so that the shield can stay connected to the jack sleeve and we can swap the signal wires without worry. Edit - ninja’d by newey. Not the first time and probably won’t be the last.
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Post by ashcatlt on Aug 10, 2022 12:10:50 GMT -5
Remember that tube amps for a given wattage are generally louder than SS amps. Is this actually true, and if so why? Like of course speaker sensitivity can play a part, but if we use the same cab…. We know that there are several different ways to measure power - peak, rms, continuous, THD tolerances, etc. So what’s actually different between a tube watt and an ss watt?
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Post by ashcatlt on Aug 7, 2022 13:37:18 GMT -5
Pick up both your feet at the same time and you’ll probably find ground pretty quick.
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Post by ashcatlt on Jul 23, 2022 0:24:24 GMT -5
Most of this video is pretty good info on the sort of broad basics of why and how EM/RFI noise is a thing and some of the ways we try to deal with. At the end, though, is a kind of crazy story. I have no reason to doubt the dude, but like JFC who would ever do that?!?
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Post by ashcatlt on Jul 23, 2022 0:21:17 GMT -5
You're not using some kind of wacky strings with no steel in them?? Lol yeah nylon strings don’t work. But I got nothin on this one. Really weird. Wish you luck! Let us know if you figure it out.
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Post by ashcatlt on Jul 16, 2022 11:14:15 GMT -5
The comb filtering comes from the fact that the harmonics are in different phases at different points in the string, so that some will reinforce between pickups while some cancel out to some degree. In order to get the strongest effect, the various harmonics want to be as close to the same level between pickups as possible. But the slope of the harmonic series is different at different spots along the string which is like the whole reason we have more than one on so many guitars. There’s no good electronic way to even out that slope. I think you’d want to target one or a couple of the out of phase harmonics and balance things so that their levels were roughly equal between pickups. Just matching the fundamentals is not going to maximize the phase cancellation. The middle pickup will probably need to be louder than the bridge and probably by a fair bit.
But honestly idk a damn thing about quack. I think there’s more to it than that kind of comb filtering. Honestly the best way to maximize it is probably the old fashioned way. Use three very similar pickups and adjust their heights by ear until you get what you want.
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Post by ashcatlt on Jul 14, 2022 19:08:22 GMT -5
Assuming you don’t need to use the second half of the Strat switch for T pot switching (just wire them across the pickups directly instead, or use master T). You’d ought to be able to connect the top end of the inductor where the bridge hot is and the bottom of it to that same position on the other side of the switch. Connect the middle position lug on that side of the switch to ground. That should make the inductor disconnected except in the bridge+middle position. In bridge-only position, it would kind of be hanging from hot, but idk how much of an issue that would be.
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Post by ashcatlt on Jul 12, 2022 13:18:03 GMT -5
Huh. If I’m reading that right, it would leave the bridge hanging upside down from hot in position 3, which may have some impact on noise performance. Other guitars like this that I’ve seen usually short the unused coil in both single positions, and that would be the way I’d probably wire it unless it’s really just trying to be like factory accurate restoration.
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Post by ashcatlt on Jul 10, 2022 9:52:35 GMT -5
It is way too early and I can’t see all the used lugs so I can quite make sense of that “original” wiring, if there are actually only two wires to other things, it almost has to be a series wiring of some sort.
That knob looks to me like it’ll give a person plenty of torque to screw up that switch pretty good. One might say it’s a good thing the whole thing spun because it’s pretty easy to crank cheaper switches like this far enough that they never work again. I also think that’s just an unfortunate spot for a switch that’s so easy to accidentally flip. My baritone has a tele style switch in approximately that position, and when I really get rocking, I still sometimes accidentally flip the thing. That situation is of course much worse since it’s not a pickup selector but a kill switch.
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Post by ashcatlt on Jul 7, 2022 16:54:06 GMT -5
Yeah I can't promise it'll actually work particularly well. I'm afraid you're going to find that most of the interesting action is very close to the extremes of the pot's travel with that pickup's contribution dropping off pretty fast as you move toward the center from either direction. Worth a try if you've got the parts laying around. If not, you could probably test it with a pair of linear pots and see if you like it.
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Post by ashcatlt on Jul 7, 2022 16:21:42 GMT -5
Yeah I guess it’s really just wired like any DPDT phase switch, except it’s a dual pot. The both have six lugs related to one another essentially the same way.
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Post by ashcatlt on Jul 7, 2022 12:51:29 GMT -5
Blending between phase on one pickup will work like turning it down to silence and then back up but this time out of phase. On its own that seems unhelpful, but combined with another pickup, you get a sort of mix control which actually could be pretty cool. The way I see it working needs a dual gang pot.
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