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Post by jhng on May 8, 2006 6:07:06 GMT -5
I'm proposing to abandon my "less is more" approach and go for versatility in preparation for a recording project I have brewing.
What I have in mind is basically:
All pickups in parallel, three volumes (one for each pickup), no tone controls, [and push/pulls to do various series things].
Hopefully, there will be lots of blending possibility.
Question: What value pots to use and should they be linear or audio taper?
Given that there will be three vols in parallel, and that I want to be able to blend quite subtley, my instinct is to go for 500k, Linear taper pots.
Opinions?
Hastings
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Post by JohnH on May 8, 2006 6:57:54 GMT -5
Hastings - I think Id agree about the 500k. Will you put the vols before the switching, so that when theres only one pup engaged, theres also only one vol pot loading it? I'll also make my usual plug for an active buffer, particuilarly where blended mixes of several pups in series are involved.
John
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Post by jhng on May 8, 2006 7:10:05 GMT -5
Thanks for the response, John.
Sorry, should have mentioned this.
No main switching at all.
The only controls on the guitar will be the three pots. One acting as a volume for each pup.
Each volume will also be a push/pull. When you pull a volume pot it becomes inactive (although it remains attached to hot) and the pickup it relates to is placed in series "behind" the next next pickup in the chain (chain going N -> M -> B-> and back to N).
I'm very resistant to the idea of putting anything active inside.
As to linear/audio taper: my thought was that linear pots would give more subtle control when blending the pickups.
What do you reckon?
Hastings
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Post by JohnH on May 8, 2006 7:21:12 GMT -5
The main issue I can see is being able to turn the volumes to zero without losing everything. Will you reverse wire the volumes? When they go into series, can the volumes be then arranged so that they lose the top leg of a reversed volume pot, ie, they are being shunted by the volume control, without adding extra resistance. I'd agreewith linear pots for this application.
John
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Post by jhng on May 8, 2006 7:50:02 GMT -5
Thanks for that.
The pots will be reverse wired so that you can select various parallel combos by turning off unwanted pups.
Originally the volume pots remained in the circuit but with the wiper is disconnected when in series mode.
But you may have inspired an improvement whereby the ground-side of the pot "follows" the ground wire of the related pup in series mode.
I'll post a couple of schematics in due course.
Thanks for your help.
Hastings
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Post by Runewalker on May 8, 2006 12:39:07 GMT -5
Another convert to the Church of the Blender! This thread prompted a memory of a long ago discussion that eventually yielded the TM-II and fed the LP Max in the Schematics subboard. guitarnuts2.proboards45.com/index.cgi?board=wiring&action=display&thread=1117172128&page=1To recap elements of the long thread that touch on jhng's idea …… exerpted for convenience" RW "…A couple of ? …... 2. If so, how would it change if there was just a master tone, but a volume control for each pup?
I use volume at the pup more for tone then the tone control….. Also, I assume I could use a push pull pot for the phase in/out switch. To bad I can't find a push/pull pot for the 4PDt switch. Crowded control cavity you know.
.JH Ill think about the separate vol controls, it may get in the way of the series arrangements however JH “Runewalker - A master tone is fine, simpler of course. But Im having trouble figuring out separate vol controls for each pup. The problem is that when you turn down volume to say halfway, the overall resistance of the pup/pot together goes up. It works fine in parallel, but joining such arangements end to end in series will not work properly. it may be possible with a dual gang pot (one side for series, the other for parallel), but havent figured it out yet. The bridge pup is the hardest to deal with on that circuit….” RW “Conventional circuits for Les Pauls have the separate volume controls. Is this resistence phenom. you describe above compounded because of the third pickup and Vol control?
If three vols. will not work properly then perhaps a dedicated vol for the Neck (which I roll up or down for base reinforcement) and a master vol for the Bridge and Mid. Is that possible?
IF the bridge was engaged, the vol would work normally for that pup
IF the Mid was engaged, the vol would work normally for that pup.
If Bridge and Neck were engaged, the vol would affect both together.
Then the other combos with the Neck.
Not trying to make things difficult. I am an old Les Paul player, and experimenting with these strat configs have raised some questions, like why be limited to a 5 way switch, and why are there no separate vol/tones for the pups?
I feel the tone alterations with the vol, are more satisfying then the freq rolloff of the Tone control….” JH: “….Runewalker - the main problem that I see with the separate vol controls is in the series setting.
If you take a guitar with standard tone control, plug in a lead and measure resistance across the jack, at full volume you have a resistance just a bit less that the pickup. But if you turn the volume half way, you get a much higher resistance, since the signal path has to pass through the volume pot. If such an arrangement is put in series with others, all of the extra resistance from all of the pots will affect all of the pickups. So they wouldn't be independent and youd get an electrical mess.
With a series connection, the way to do separate vol controls would be just to wire two connections to the pot, as a variable resistor which more of less bypasses the pickup. Then if you turn it all the way down, the coil is fully bypassed and the signal can pass directly to the next pup in the series chain. This is not good for a parallel arrangemet though, bypassing one pup would also short out all the others. The only way I can see to do it is in a dual gang arrangement. With my circuit, I think this would work on the neck pup, and heres a schematic, clipped from the full diagram (sorry, youll have to try to follow it!)
Most vol controls have the wiper (moving) conecction towards the output. This is good for a master control, but can reduce volume on other pups if used for separate vol controls, so for the parallel side Ive shown it reversed, with wiper towards the pup . That way you can have a small boost of neck sound without compromising the sound from the other pups.
Its a good idea of yours to do this just to one pup, with a master vol. i cant get this arrangement to work on the bridge pup, due to the way it is wired in this circuit (not saying its impossible, just cant figure it out).
Of course, if you dont need neck vol control in both series and parallel, a single pot will do…” So history is being revisited, albeit with differences, and in that thread, rather than 3 vols it went in another direction towards the blender design. I still like the 3 volume idea, at one time JH had concerns about that being too "wooly." But more experiments have been conducted since that concern was articulated. So let me ask a couple of questions to explore some options on this 3 pup, 3 vol, no tone array: Respecting jhng's desire to have only P/P on/offs for the pups activation inactivation, let me none-the-less ask a theoretical question. Could the TM-II be adapted to this 3 pup, 3 volume control, no tone control, notion? I.e., on/off toggles for bringing the pups in or out of the circuit, and a 4PDT for the System Seri/Para switching. Would there be any downside to upping the pot values to 1M? RW
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Post by sumgai on May 8, 2006 16:55:27 GMT -5
Time to jump in and get my feet...... muddy. Hastings, I'd not go for the linear taper. You want subtle control? You want as much "fine" control over as large a rotation-range as possible, right? Well, figure it out..... when you rotate a linear pot 50%, you get a 50% change in overall resistance. But in a log taper pot, only about 25 or 30% or rotation gives you that same 50% change in resistance. In a normal taper pot, that rapid change occurs from the full stop at CCW, and in the direction of CW (as facing the pot from the front, or the user-accessible side). That leaves you with 70 to 75% of the total rotation-range to make changes in only 50% of the total resistance. Does this not sound like more control to you, giving you a greater chance at achieving subtlety? Here's a switch (pun fully intended!): I'd eliminate all on/off switching entirely, and just relay on the pots to fade the pups down below the threshold of audibility. Wire the pots forward, to keep the loading of each pup "local" - only its own pot will affect it (for the most part). To keep from killing the whole output, suspend the terminal that's normally grounded with a 47K resistor between that terminal and ground. Presto!, no chance of totally grounding the signal, should you crank it down all the way. The total output may drop a bit, but some experimentation will find a value that gives you the best results. At that point, you may also feel the need to change your pot values from 250K down to 100K. Don't worry, if there's more tha 47K in the bottom leg, the total resistance will still be a sufficient load for the pup. Did all this make sense, or should I post a drawing? sumgai
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Post by UnklMickey on May 8, 2006 17:13:29 GMT -5
Sumgai,
while i applaud the creative thinking you put into this, i suspect there may be some undesired effects.
with 3 forward wired volume controls in parallel, if one is at full volume, and the other 2 at minimum,
the load on the full volume pickup will be ~25k.
so the sound from that pup will get even muddier than your feet.
so i think at best, this idea needs a bit of tweaking before it's ready to fly.
unk
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Post by ChrisK on May 8, 2006 17:29:28 GMT -5
My recent tests on the TeleBlender indicated that the best parallel blending occurred, with the pickup hot going to the wiper, down to about 200K on the high side of the pot (wiper to top lug). The best series blending occurred over a range of 0 to about 200K in parallel w/ the pickup.
Based on this, for single coil or stacked humbuckers, I will use a 250K effective resistance. This will be from native 250 K pots, or from linear 500K pots parallel tapered to my preference.
Also, make sure that you switch directly to the pickup wires when in series. You only want resistance in parallel with the pickup (shunt resistance).
Take a look at the TeleBlender and at my posts in Electronics & Wiring/Schematics/Modules for some insight into blending structures.
For your design, treat each pickup and pot as a three-terminal element.
"A" is the common/pickup return/pot low lug (CCW).
"B" is the pickup hot wire connected to the pot wiper.
"C" is the pot top lug (CW).
For parallel, connect all "A" points to common. Connect all "C" points to the output.
For the neck in series, if you want the precedence to go N>M>B, the neck "B" must be switched to the now lifted common of the middle and bridge and the neck "C" should go nowhere (or to "B"). [N*(?M+?B)].
For the middle in series, if you want the precedence to go N>M>B, the middle "B" must be switched to the now lifted common of the bridge and the middle "C" should go nowhere (or to "B"). [?N+/*(M*?B)].
I have to think about the validity/sanity of N>M>B>N>M>B>N>M>B>N>M>B>N>M>B>N>M>B>N>M>B>etc. in a three dimensional universe.
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Post by jhng on May 9, 2006 6:32:43 GMT -5
Thanks for all the valuable input! Here's a drawing of my original idea: Edit: Oops, I've just realised that Version 2 doesn't work because I got the switches muddled up... In view of Sumgai's comments and ChrisK's experimental research, it also occurs to me that using reverse taper logarithmic pots might give even more blending subtlety? The basic idea is to get all the in phase combos except the (series-dominant hybrid ones), with lots of blendability in the parallel combos. In a fairly logical way. Although I am slightly concerned that the whole thing may just sound like mud on account of the 3 vols (I think it works out as a load of about 185k). BTW, I have spotted the fact that with all push/pulls pulled there will be no sound (and the pups will all be connected together in a daisy chain)! Hastings
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Post by jhng on May 9, 2006 10:12:38 GMT -5
I've just had a horrible thought:
Could have the pups connected in a circle (as would happen with all three push/pulls pulled out) damage the pickups?
I think the possibility of blowing a pup is best avoided in any wiring scheme...
Hastings
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Post by sumgai on May 10, 2006 1:28:14 GMT -5
Hastings, No, there's no chance of damaging your pickups, no matter how they're wired - not even in a direct short circuit. The reason is, the miniscule amperage developed within each coil is not sufficient to cause the electrons flowing within the coil wiring to heat it up at all. Moral of the story: a coil generates voltage, at very low levels of current. You can verify this without an expensive ammeter by using Ohm's Law, and the measured output voltage and measured resistance. Roughly, an 8K ohm coil, divided by 1.25 volts, will yield 1/10th of a milliamp! (Impedance will come into play only if you are concerned with frequency response, so don't worry about that for the purpose of this exercise.) Going further, just because I have the rest of the evening to kill, ;D we'll look at the ampacity of the common wire size found in most pickups, 42 gauge. On the web, I found that this wire has the ability to carry 0.010 amps, or about 10 milliamps (in free air). This is 100 times the amount of amperage developed within our hypothetical coil, so even if we give a safety margin of 4 to 1 (the coil is enclosed, not in free air), we still have a factor of 25 to overcome before we exceed the wire's ability to carry the current without self-destructing. Had enough? Good, me too. sumgai
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Post by jhng on May 10, 2006 5:22:17 GMT -5
Thanks, Sumgai. Very illuminating!
I guess I should try and get a better grip on actual electronics know-how (rather than just seeing guitar circuits as logic problems).
I think I'm going to try Version 2 at the outset [edit: no I'm not...see above] , using 500k linear pots. And then modify it as necessary.
Although, having looked at ChrisK's blender circuits - I am toying with the idea of trying to make each pup volume remain effective in series mode...
Hastings
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Post by jhng on May 10, 2006 9:06:58 GMT -5
Ok, here is a further version: This time I've tried to incorporate some of ChrisK's ideas about series blending. Now when a pot is pulled: it puts it's related pickup in series with whatever is above it in the B>M>N>B>M>N (etc etc) chain, and then acts as a fader to fade down it's related pickup and anything ground-side of it in the chain. This gives some series blending opportunities, although they are by no means comprehensive. But my attempts to go any further always end up compromising the way the volumes work for parallel settings. In particular, I am keen that in A+[B*C] linkages, the parallel blending takes priority over the series blending. I'm still leaning towards 500k Linear pots. Many thanks for the invaluable comments. I think it's almost time to order parts and give it a whirl... Hastings
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Post by sumgai on May 10, 2006 15:04:11 GMT -5
Errrr, Hastings? When all three switches are flipped to series, wherefrom does the output get any signal at all? It's the same problem as your earlier circuit, except for the switches being positioned after the volume pots instead of before them. In your current incarnation, you aren't allowed to flip all three switches, or else you get phffffft. That makes it more of a "user-unfriendly" kind of thing, to be sure, but still, in the heat of the moment, accidents do occur. Might I recommend that you consider using 4PDT switches instead, and using the "new" poles to institute an "exclusive-or" scheme. Moreover, depending on which two switches you've flipped to series, the remaining volume control in charge also changes - the position of the sole volume pot on the face of the guitar is playing the shell game with the user. Now we're stepping into "user-hostile" territory, to my way of thinking. Given your current design constraints, this is gonna be a tough nut to crack - I have no suggestions at this time, sorry. sumgai
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Post by jhng on May 12, 2006 6:16:25 GMT -5
Errrr, Hastings? When all three switches are flipped to series, wherefrom does the output get any signal at all? It's the same problem as your earlier circuit, except for the switches being positioned after the volume pots instead of before them. In your current incarnation, you aren't allowed to flip all three switches, or else you get phffffft. That makes it more of a "user-unfriendly" kind of thing, to be sure, but still, in the heat of the moment, accidents do occur. Might I recommend that you consider using 4PDT switches instead, and using the "new" poles to institute an "exclusive-or" scheme. Moreover, depending on which two switches you've flipped to series, the remaining volume control in charge also changes - the position of the sole volume pot on the face of the guitar is playing the shell game with the user. Now we're stepping into "user-hostile" territory, to my way of thinking. Given your current design constraints, this is gonna be a tough nut to crack - I have no suggestions at this time, sorry. sumgai Sumgai, Thanks for the heads up, but... That's the "all pups off" position ... it was also the reason why I asked about the risk of pup damage earlier on (which you gave a very helpful and illuminating reply to, +1). Although I haven't yet pulled out three push/pulls at the same time, by accident; I do see the risk and find it acceptable. As to the shell game effect, it's slightly diminished by the fact that the active volume in that situation is always the one which hasn't been pulled out. Given that pulling two push/pulls out always gives all three pups in series (which I don't use much), I doubt it will be a problem. I think I'm going to try one of these ideas at this point and see how it goes. I'll report back! Hastings
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Post by ChrisK on May 13, 2006 0:56:45 GMT -5
Yeah, tubular (circular) logic dude.
With all three pickups in a circular loop, you've essentially created a three coil series pickup THAT IS SHORTED!
You also have created a three-coil delta structure that (while still being shorted) has the possibility of all three nodes (element junctions) being varied from common to output.
Something WILL happen, you MAY hear some level of output, you won't start any fires (outside of your psyche) AND
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Post by jhng on Jun 5, 2006 11:11:54 GMT -5
Hello all,
A quick report back.
Having played around with the blending thing a bit, I confess I abandoned this one as "nice in theory but distracting in practice", and a bit short on sparkle.
Have now gone for the boringly conventional:
5-way switch, Volume (500k audio), push/pull.
Standard Strat in Mode A and as follows in Mode B (x = series; + = parallel):
NxB (NxB)+M MxB N+B B (with a 0.01uf capacitor across it).
But the discussion was fascinating! And the "three coils in a loop" idea definitely has potential for some kind of "do everything" wiring scheme.
Hastings
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