Help understanding a tone knob value in relation to a volume pot

[midwayfair]

I feel like I should be be able to figure this out on my own, but no dice ...

Really simple high cut tone knob: A cap in series with a pot to ground, coming from the wiper of a voltage divider volume knob.

Does the actual value of the volume pot factor into what value can be used for the tone pot? If, say, the volume is 10K or 100k, will a tone knob of, say, 500K stop doing anything after the base value?

I've been testing it, and I swear it's all bunching in one side of the sweep regardless of whether it's a linear or audio pot, but I'd also swear that there's at least a slightly audible difference at all points in the sweep.

I'm trying to use a large value to avoid resistance loading on the volume circuit, but it's clearly having an undesirable effect on the function of the tone knob.

If I do need to change the value of the volume pot to get closer to a match, is the solution to put the large vp in parallel across another resistor on the board?

[jkokura]

I wonder if the Duncan Tone Stack Calculator would be helpful for you...

Jacob

[midwayfair]

I wonder if the Duncan Tone Stack Calculator would be helpful for you...

Jacob

I've got Duncan's tone stack calculator and I've used it for a Big Muff tone control. Apparently what I'm trying to learn is too simple for it to be helpful - there's no tab for a guitar volume style cut (volume pot, tone pot, and cap). It's not a tone stack, just a single knob.

[jkokura]

I wish I could help you. I imagine that if someone doesn't pipe up here you could try over at DIY Stompboxes. I'm sure some of the guys over there, like R.G. or Mark Hammer for example, would be able to help you understand better.

[midwayfair]

I wish I could help you. I imagine that if someone doesn't pipe up here you could try over at DIY Stompboxes. I'm sure some of the guys over there, like R.G. or Mark Hammer for example, would be able to help you understand better.

I appreciate it, thanks.

[mgwhit]

What you're describing sounds like the so-called Fifties Mod Gibson tone control wiring.  Volume pot as a voltage divider, wiper feeding both (a.) Tone cap through Tone pot as a variable resistor to ground and (b.) the output to the jack.  If so, there's a never ending debate about what that accomplishes.  Google it.

What I will say, is that you're essentially creating a low-pass RC filter and that the resistance between the input and wiper lugs on your Volume pot will affect the corner frequency.  Of course this is all complicated by the presence and setting of the Tone knob and possibly irrelevant if you have the volume all the way open.  Apologies if I'm mis-visualizing this, and good luck!

[midwayfair]

What you're describing sounds like the so-called Fifties Mod Gibson tone control wiring.  Volume pot as a voltage divider, wiper feeding both (a.) Tone cap through Tone pot as a variable resistor to ground and (b.) the output to the jack.  If so, there's a never ending debate about what that accomplishes.  Google it.

What I will say, is that you're essentially creating a low-pass RC filter and that the resistance between the input and wiper lugs on your Volume pot will affect the corner frequency.  Of course this is all complicated by the presence and setting of the Tone knob and possibly irrelevant if you have the volume all the way open.  Apologies if I'm mis-visualizing this, and good luck!

You're pretty much described most of what's happening, and yes, 50's wiring was the basic model for what I'm doing.

Mark Hammer was kind enough to weigh in on DIYstompboxes and he says mostly the same thing:
http://www.diystompboxes.com/smfforum/index.php?topic=97205

[jkokura]

I knew Mark H. would be able to help you. Glad Matt could help too - he's generally a helpful guy.

Jacob