|
|
Post by unreg on May 6, 2021 21:45:33 GMT -5
hi all!  I have decided on the sound I want from my guitar when both humbukers are used; the tone knob is almost at max. When switching to just the neck bridge humbucker, I need to turn the tone knob down just a little. A 8th of an inch turn of my A500k tone pot would be about right. Is there a way to make my guitar change that small tone difference automatically after just flipping the 3way pickup switch to/from the 3rd position? Thank you for reading. 🙂 EDIT: Now this thread is way confusing bc I’m an idiot. The “bridge” change here happened after my post replying to Yogi B. |
|
|
|
Post by roadtonever on May 6, 2021 21:54:29 GMT -5
You can add a resistor between neck PU wire at the switch and ground. The correct resistor value is hard to say without knowing the exact taper, something in the hundreds of kOhm.
|
|
|
|
Post by unreg on May 6, 2021 22:19:12 GMT -5
Thank you roadtonever! 👍😀 Honestly, my post above was rushed. Maybe an 8th of an inch turn would be way too much; just looked at a ruler. Would trying to emulate a 16th of an inch turn, make a difference in the number of 100s of kohms resister I’m looking for? Does “taper” mean how much the tone knob reduces the signal? It’s a “CTS Control PotsLong split shaft, 500K-ohm (CTS #450S 3486)” from StewMac, if that helps. |
|
|
|
Post by newey on May 7, 2021 5:47:53 GMT -5
unreg: According to Stew-Mac's website, those are audio taper pots, also called "logarhythmic taper", usually shorted to "log taper". These are typically used in guitars, as opposed to linear taper pots, although some folks do prefer the linear taper pots for some purposes. There are also "anti-log" or "reverse log" pots, used in lefty guitars as well as for other purposes. No, it's the way in which it does so. A linear taper pot rolls off in a linear fashion- if you made a graph as you turned the knob, the graph would be a straight line. At "5" on the pot, the resistance is halfway between "10" and "0". But the human ear doesn't hear things that way- our ears are attuned to higher frequencies more than lower ones, we don't hear in a linear fashion. So, while a linear pot is electrically halfway at "5", you wouldn't hear "5" as being halfway. Log pots are designed to respond in a way closer to what we hear. If you graph the response, it's a logarhythmic curve, like a hyperbola (well, sort of, anyway- it's actually a series of linear segments to approximate a log curve). Here's a graph, courtesy of the late ChrisK, showing the differences. (Note, however, that Chris's designation of the curves as "U", "A", "B" is non-standard; when buying pots, log pots are designated as type "A", linear as type "B" and reverse log as "C"):  But, just know that, for what you want, audio taper is fine. As far as what resistor value would work best, you can test for this to "dial in" the response you want, using a spare pot and a scrap guitar cord that you don't mind sacrificing, and some alligator clips to make the connections. To do so, you would split open the guitar cable so that you can access the wires. Then, temporarily wire the spare pot "across" the cable, using the clips to make the connections so you can easily disconnect it- counterclockwise lug to the guitar "hot" end, center terminal to the amp "hot", and clockwise lug to the shield (ground) of the cable. Plug in, turn on the neck pickup with the other pots at "10", and dial the temporary pot to where you like the level. Then, being careful not to move the knob, disconnect the pot and measure the resistance. Whatever standard resistor value is closest to your measurement will be what you want.
|
|
|
|
Post by ashcatlt on May 7, 2021 13:44:31 GMT -5
The actual problem here is that there’s no good way to wire this without also affecting the middle position. I didn’t notice if we’re talking about a fender or Gibson style switch, but it doesn’t matter. Neither will work. If you have a tele switch, I think you might could get close to what you want via series resistance(s), but the Gibson won’t do that either.
|
|
|
|
Post by unreg on May 7, 2021 16:42:25 GMT -5
newey, thank you so much for the detailed response! 👍😀 A question: Do your clockwise/counterclockwise notes describe a pot inverted or knob side up? Just wondering… —- I didn’t notice if we’re talking about a fender or Gibson style switch, but it doesn’t matter. Ummm, frets said it’s: a standard 8 lug 3 - Way Import Switch.
|
|
|
|
Post by newey on May 7, 2021 18:35:28 GMT -5
|
|
|
|
Post by unreg on May 8, 2021 0:18:11 GMT -5
Thank you sir newey! 👍😀 That helps a ton! |
|
|
|
Post by unreg on May 25, 2021 23:07:38 GMT -5
The actual problem here is that there’s no good way to wire this without also affecting the middle position. I didn’t notice if we’re talking about a fender or Gibson style switch, but it doesn’t matter. Neither will work. If you have a tele switch, I think you might could get close to what you want via series resistance(s), but the Gibson won’t do that either. So, this fix is not a correct fix? Would wiring/solder-spots affect this a-little-too-much-treble-when-only-bridge-pup-is-selected semi problem? But, you said, “there’s no good way to wire this”. We have: 1.) neck+bridge humbucker is good 2.) just neck humbucker needs tiny treble reduction a.) if I reduce the treble from my neck humbucker, then that will also reduce the treble sent to switch position 2. b.) so, would increasing the treble on the neck humbucker in an exact inverse from a resistor attached to switch position 3, make this work? No? I’d have to use another guitar cable test to figure out that increase-treble-value-on-neck-humbucker-value? c.) is this possible with my import switch? I’m just trying to figure if this is possible, even though you’ve told me there’s no good way to wire this… haven’t added any resistor yet. EDIT: Is there even a way to inverse resistance? |
|
|
|
Post by Yogi B on May 26, 2021 3:07:56 GMT -5
The tone knob is almost at max. I'm assuming that "max" means maximum brightness. (Most people have a strong mindset of the loudest volume & brightest tone are the default, but there is a small number of people who confusingly take this idea a step further: those for whom "at maximum" actually means "has the maximum difference from the default", i.e. the quietest/darkest setting.)
Side note:
If you accurately wanted to report the rotation you're looking at the wrong measuring instrument, you should've looked at a protractor.
One cannot measure rotation using lengths -- at least, not without knowing the size of the object being rotated. For a typical Tele style knobs (~19mm) a 16th of an inch rotation of the circumference is about 10 degrees, whereas if you're using slightly larger speed-style knobs (~26mm) that'd be only 7 degrees, and if your guitar happened to have knobs with the circumference of the earth (~40,000km) it'd be roughly 0.0000000045 degrees.
However, in reality, even an exact rotation measurement wouldn't be a great help due to the wide tolerances of potentiometers -- the best way to get the resistance you're after is either by directly measuring the resistance of temporary additional pot or by using a trimpot as an adjustable resistor in the final wiring.
The actual problem here is that there’s no good way to wire this without also affecting the middle position. I didn’t notice if we’re talking about a fender or Gibson style switch, but it doesn’t matter. Neither will work. If you have a tele switch, I think you might could get close to what you want via series resistance(s), but the Gibson won’t do that either. Assuming were talking about basically 'standard' Tele wiring, but with extra loading on the neck only position -- Fair enough, a (typical) Gibson switch, but why wouldn't this be possible for any 7 or 8 terminal Tele switch? | Common | Pos #1 | Pos #2 | Pos #3 |
|---|
| Volume Input | Bridge | Bridge | Load to GND | | Volume Input | | Neck | Neck |
(And to address my earlier parenthetical, similar can be achieved with the special 3-pickup LP toggle switches.) As for what the unspecified extra loading should be, as mentioned earlier an exact value would be difficult for anyone other than unreg to determine, but 100k-300k would be in the ballpark. I will also note that using any fixed resistance value will give the most difference between positions when the main tone control is at it's brightest setting -- as the tone control is reduced, the extra loading of the additional resistor will lessen in comparison to the increased loading already applied by the tone control. Thus, if it is important that the neck pickup is consistently darker than it is currently, no matter the position of the master tone, any solution would require a dual-gang pot for the tone control. The reverse log, I was under the impression it went the other way:  Both are correct: it depends between which two terminals one is measuring the resistance. The diagram you posted assumes that the same two terminals are used for the 'normal' and reverse logarithmic tapers, which is arguably the most sensible thing to do. However, for a reason unbeknownst to me, in most manufacturers' datasheets they'll measure the reverse taper between the wiper and the other outer terminal. In practical terms this is equivalent to subtracting the plotted percentage resistance away from 100%, or vertically flipping the plotted line. |
|
Deleted
Deleted Member
Posts: 0
Likes:
|
Post by Deleted on May 26, 2021 3:45:45 GMT -5
I wasn't 100% sure so I deleted the post at the same time you where replying .. SORRY
|
|
|
|
Post by roadtonever on May 26, 2021 11:15:48 GMT -5
You have one situation that's known to be desirable for you based on you turning your tone knobe down: adding extra resistance to the S in a HS setup.
It brings another situation where when both pickups are selected: the extra resistance is still active bringing the brightness for that position down too. It's unknown whether you will like this secondary change or not. It might work out for you, arguably and the middle tends to be pretty bright/scooped to begin with. You might hate it in, that case a more sophisticated circuit needs to be worked out.
|
|
|
|
Post by ashcatlt on May 26, 2021 17:02:20 GMT -5
...but why wouldn't this be possible for any 7 or 8 terminal Tele switch? | Common | Pos #1 | Pos #2 | Pos #3 |
|---|
| Volume Input | Bridge | Bridge | Load to GND | | Volume Input | | Neck | Neck |
Oh. I...uhhh...don't know what I was smoking that day. You are correct of course. Sorry about that. |
|
|
|
Post by unreg on May 27, 2021 11:38:38 GMT -5
The tone knob is almost at max. I'm assuming that "max" means maximum brightness. It does equate to maximum brightness; but, by “max”, I was thinking of how we are told to make sure that pots are off before applying solder… “max” is supposed to be the inverse of off.
Side note:
If you accurately wanted to report the rotation you're looking at the wrong measuring instrument, you should've looked at a protractor.
One cannot measure rotation using lengths -- at least, not without knowing the size of the object being rotated. For a typical Tele style knobs (~19mm) a 16th of an inch rotation of the circumference is about 10 degrees, whereas if you're using slightly larger speed-style knobs (~26mm) that'd be only 7 degrees, and if your guitar happened to have knobs with the circumference of the earth (~40,000km) it'd be roughly 0.0000000045 degrees. 😮 I’m not big enough to lift a guitar with knobs with the circumference of the earth. 😋 Hmmm… in degrees, I guess it is only about at max a 5 degree turn, maybe even less. Superb idea using degrees for measuring turns Yogi B! 😀 However, in reality, even an exact rotation measurement wouldn't be a great help due to the wide tolerances of potentiometers -- the best way to get the resistance you're after is either by directly measuring the resistance of temporary additional pot or by using a trimpot as an adjustable resistor in the final wiring. An adjustable resistor trim pot sounds excellent; however, I’m not going to put another hole in my guitar… wait, the trimpot could sit underneath the guitar… I’d adjust it once and leave it alone? | Common | Pos #1 | Pos #2 | Pos #3 |
|---|
| Volume Input | Bridge | Bridge | Load to GND | | Volume Input | | Neck | Neck |
(And to address my earlier parenthetical, similar can be achieved with the special 3-pickup LP toggle switches.) Does your table suggest I need two volume pots? Or do I add a 3-pickup LP toggle switch to each volume pot lug? Your table doesn’t mean I should wire both gnd and neck to Volume lug #3, right? (I’m referring to his html table he used; I’m pretty sure I didn’t know the table tag even existed here on proboards.) As for what the unspecified extra loading should be, as mentioned earlier an exact value would be difficult for anyone other than unreg to determine, but 100k-300k would be in the ballpark. I will also note that using any fixed resistance value will give the most difference between positions when the main tone control is at it's brightest setting -- as the tone control is reduced, the extra loading of the additional resistor will lessen in comparison to the increased loading already applied by the tone control. Thus, if it is important that the neck pickup is consistently darker than it is currently, no matter the position of the master tone, any solution would require a dual-gang pot for the tone control. The neck humb is not important, AAAH! 😱 When switching to just the neck bridge humbucker, I need to turn the tone knob down just a little. I had a good(?) question here, but now my mind is all confused as to why I talked about the neck humb in the beginning… so maybe I’ll edit this again after my mind returns. Sorry. 😔 —- Oooh, thank you Yogi B! 😀 |
|
|
|
Post by newey on May 27, 2021 11:59:47 GMT -5
Yes, YogiB is referring to a trimpot sized to be soldered to a printed circuit board. You set it where you want it and stash it in the cavity. It's light ehough that it can just hang off the wires without stressing the solder connections, you don't need to even mount it to anything.
|
|
