Noob question using pot as a variable resister to ground

[Tone Junkie]

Ok so i want to use a pot as variable resister to ground, to dial the right amount of bleed off to make my channels sync up strength wise when switching between them. this resister is to high this one to low so I need a pot so I can dial it in. so do I wire it up looking from the back of the pot the center and left tyed together to ground and signal on the right or how should I wire it. Bill

[LooseChange]

You should still wire it as a potentiometer and not a rheostat.

[Tone Junkie]

Please explain my friend I know just enough to be dangerous but not enough to understand the differance between what your saying, so how would I wire that please explain. Im a noob man it sucks. Bill 

[tubeswell]

volume pot = input signal goes to 'input' lug, output lug goes to the chassis ground return, the wiper lug goes to the output signal

variable resistor = input goes to 'input' lug, wiper lug goes to output (and is often tied to 'output' lug as an added precaution if the wiper contact fails)

[Tone Junkie]

Thank You, Thank You, Thank you, that I understand so basicly kind of like i said in the begining. I would use a resister ahead of the pot to get in the ballpark of the area i want to dial in so it would never leave it open if the wiper contact failed. Thanks Tubeswell someday you guys will have me trained and I wont ask so many noob questions.a person can read and read and still miss the simple things untill your staring them in the face. Bill

[John]

TJ, I'm glad you asked this question, as it's only one of many that have floated through my mind. That I forget to write down. 

[tubeswell]

The 'volume pot' application is just a variable voltage divider, whereby the input voltage sits at the 'top' (input lug) of the divider, and the wiper is the moveable 'knee' (output) of the voltage divider. With the wiper set to 'zero', you end up dumping all of the output of the divider straight to ground.

At any one setting, the resistance 'beneath' the wiper, in proportion to the total resistance of the pot between the (top) input and the (bottom) ground, represents the relative strength of the output voltage at the wiper (knee) compared to the voltage at the input.

For example, say you had a 1M linear pot with the wiper set at 400k rotation from the bottom.  The voltage output at the wiper lug, compared to the voltage at the input lug is: 400k/(400k + 600k) = 40%.  So a 20VAC signal at the input, would end up being 20 x 40% = 8VAC at the wiper, and so on.

[Tone Junkie]

Thank you tubeswell that was very helpfull you now have your first post on my wall of knowledge I need to remember.
 Damn late seventies early eighties shure didnt help with my memory loss 

[Shrapnel]

Use the volume pot as level controls for each channel, and then mix the signals. If you need it for convenience to adjust the overall volume, add a single "master-volume" where you'd normally (pre or post PI.)

So what you might have is (without a master-volume, and assuming Tone-stack after all gain stages):

v1-GAIN-v1-...-Ts-LEVEL-Mix-Pi-Pa
v2-GAIN-v2-...-Ts-LEVEL-/

(Isn't ASCII art fun????)

[Tone Junkie]

Shrapnel my friend you miss understood me. on my gain stages i will use a dropping resister to bleed off some of the signal to ground usually a 220k will bleed off enough to match that up with the original signal so I dont have a huge volume boost when i kick in the extra gain stage. On this amp im designing im putting together a marshall 59 with 2203 and an extra gain stage all foot switchable. but this time i want to dial the voltage swings to the knats ass and use a 100k resister then a 220k pot to dial the perfect amount of resistance to have no volume boost when i hit the switch. at least in my feeble mind thats how i hope it will work   Bill
Tubeswell was giving me the volume pot example so i could understand how you would wire a pot as a variable resister

[Shrapnel]

Shrapnel my friend you miss understood me.

Tubeswell was giving me the volume pot example so i could understand how you would wire a pot as a variable resister

Ok, I erred (to err is human...)  with my understanding of what you were doing. Your explanation of what you had in mind is clearer now.