Strat switch

[heisthl]

Say you have a 100k linear pot wired as a variable resistor, at mid point it reads 50k to ground. Now take a 200k pot and put a 200k reistor across it, at mid point it reads 66.67K, at 25% it reads 40k(instead of 25k) etc.

[greiswig]

Say you have a 100k linear pot wired as a variable resistor, at mid point it reads 50k to ground. Now take a 200k pot and put a 200k reistor across it, at mid point it reads 66.67K, at 25% it reads 40k(instead of 25k) etc.

I sit corrected.

[skyboltone]

As far as hanging a resistor on the pot, you'd lose the taper these things seem so touchy about. Doing both pots took 15 minutes and five of that was doing one twice and taking some pictures. Even if the experiment is a total bust, you're only out six bucks.

I'm not sure whether you're referring to my earlier suggestion that you could switch a resistor in, in parallel between the tied wiper/lug1 and lug2, but if so I can't understand how a parallel resistor would affect the taper at all. It would change the Y axis values, but the shape of the taper should still be the same, shouldn't it?

I made up a jig with a multiturn 1-10 scaled knob and tried it with both tapered and linear pots between #1 and #3. I then plotted the resistance curves on graph paper. It turns both type pots into weird anti-log tapers. The only use I could see in a parallel resistor is if you didn't care if the numbers made sense but just experimented until you found a spot you liked and left it there. I haven't tried the suggestions in "The secret life of pots" yet.

[greiswig]

As far as hanging a resistor on the pot, you'd lose the taper these things seem so touchy about. Doing both pots took 15 minutes and five of that was doing one twice and taking some pictures. Even if the experiment is a total bust, you're only out six bucks.

I'm not sure whether you're referring to my earlier suggestion that you could switch a resistor in, in parallel between the tied wiper/lug1 and lug2, but if so I can't understand how a parallel resistor would affect the taper at all. It would change the Y axis values, but the shape of the taper should still be the same, shouldn't it?

I made up a jig with a multiturn 1-10 scaled knob and tried it with both tapered and linear pots between #1 and #3. I then plotted the resistance curves on graph paper. It turns both type pots into weird anti-log tapers. The only use I could see in a parallel resistor is if you didn't care if the numbers made sense but just experimented until you found a spot you liked and left it there. I haven't tried the suggestions in "The secret life of pots" yet.

That thought occurred to me after heistl corrected me: the taper should only really matter to you if you are really concerned about whether straight up (or some other arbitrary value of the control) really means halfway on the control. Putting in a parallel resistor might make you set up your TMB controls at 12:00, 9:00 and 12:00 respectively, but so what?

In a case like this strat switch idea, some might actually find that they liked the mids a bit higher in the Skyliner position, in which case the fact that a parallel resistor puts the value slightly higher might actually help, not hurt.

Care to elaborate on "secret life of pots?" I read the sequel about bees, but not the one about pots.

[skyboltone]

I'm not sure whether you're referring to my earlier suggestion that you could switch a resistor in, in parallel between the tied wiper/lug1 and lug2, but if so I can't understand how a parallel resistor would affect the taper at all. It would change the Y axis values, but the shape of the taper should still be the same, shouldn't it?

I made up a jig with a multiturn 1-10 scaled knob and tried it with both tapered and linear pots between #1 and #3. I then plotted the resistance curves on graph paper. It turns both type pots into weird anti-log tapers. The only use I could see in a parallel resistor is if you didn't care if the numbers made sense but just experimented until you found a spot you liked and left it there. I haven't tried the suggestions in "The secret life of pots" yet.

That thought occurred to me after heistl corrected me: the taper should only really matter to you if you are really concerned about whether straight up (or some other arbitrary value of the control) really means halfway on the control. Putting in a parallel resistor might make you set up your TMB controls at 12:00, 9:00 and 12:00 respectively, but so what?

In a case like this strat switch idea, some might actually find that they liked the mids a bit higher in the Skyliner position, in which case the fact that a parallel resistor puts the value slightly higher might actually help, not hurt.

Care to elaborate on "secret life of pots?" I read the sequel about bees, but not the one about pots.

Now where was that url......oh yea here:
http://www.geofex.com/Article_Folders/p ... tscret.htm

[Luthierwnc]

Er, uh, what heisthl said.

Here's my stage routine. Take off the 336 copy, put on the Strat, switch the switch and maybe a small adjustment of the knobs. Takes no longer than change guitars, small adjustment of the knobs.

What I am trying to avoid is having to decide between taking my favorite guitar or my favorite amp. Old habits die hard.

[skyboltone]

Er, uh, what heisthl said.

Here's my stage routine. Take off the 336 copy, put on the Strat, switch the switch and maybe a small adjustment of the knobs. Takes no longer than change guitars, small adjustment of the knobs.

What I am trying to avoid is having to decide between taking my favorite guitar or my favorite amp. Old habits die hard.

So? How does it work? Does it get rid of the Strat buzz?

[Luthierwnc]

I can't say yet but with the separate grounds it ought to be just like two independent preamps. That build is far enough down the list that I doubt I'll get to it before summer. I've got two classical guitars that are ready to bind (about 2/3 done, not including the finish) and two electrics that are in for some extensive repairs. They have to get out the door first.

Amp-wise, I am ready to spark-test an HRM tomorrow and am in the board building stage of a low-volt, class-A head. I do have a lot of the parts for the Strat-switch ODS but they will be on the shelf until the classicals are French-polished. Hopefully, I'll be able to mill up a bunch of binding strips and get them bent tomorrow as well. This batch is Cocobolo and that can be pretty fussy if you catch some runout in the grain -- high level of rejects.

The day job gets in the way too

Cheers, Skip