Volume Pot (Won't cut volume 100%)

[Tony]

Hi,

  I was wondering if someone might be able to offer advice concerning a volume pot that will cut the volume about 90%, but still lets some volume leak through. Any advice on how to fix this would be greatly appreciated.

Thank you,
Tony

[mikeb]

It's possible you don't have the third leg of the pot grounded, and it's just acting as a variable resistor. Without the pedal wired up, place one lead of a multimeter on ground, and the other on the wiper of the pot in question. Turning the pot from minimum to maximum should give you an idea of what the problem is (minimum -> 0 ohm reading, max -> reading close to value of the pot). Let us know what happens!

Mike

[Tony]

Hi,

  Thank you for the reply. I'm using a plastic box so there's no chasis ground. I have the 3rd tab wired to the pots casing. Any ideas?

  I will try your Ohmeter suggestion. Thanks again.

Tony

[petemoore]

Is one of the outside lugs of the pot connected to ground or another resistor or something else?

[Tony]

I have the #1 lug hooked up to the circuit board ("board out"), the #2 lug is going out to the hot tab of the out jack. #3 lub is soldered to the metal casing of the pot.

[RDV]

The #3 tab should also be hooked to your circuit ground.

RDV

[dolhop]

Connecting the third lug to the pot casing is not good enough unless the chassis is metal (which will connect the jack ground to the pot).  Solder a wire from the pot casing or lug #3 to the board ground.  This ground and the grounds from the input and output jacks should be connected to one spot which should be close to the input section of the circuit - this will minimize noise.

[the_badcliff]

When these guys say connect it to circuit ground that usually means connecting to the negative side of the battery.  Just making sure you knew.

[Paul Marossy]

Bottom line is connect all grounds together, especially with a plastic enclosure.

[dolhop]

....and try to get them to a single location to avoid ground loops.  The negative terminal of the battery is not always signal ground......specifically, when the bias point is V/2....

[Tony]

Hi,

  Yeah... I wired all of the ground connections to the ground lug on the jack, it works great now.

  (By the way, its a photocell theremin). Thanks for the help. Nice people in this forum, I appreciate it.

Tony

[Paul Marossy]

Cool. Have fun!  

[DaKurt]

I have another question. My effect makes some noise, although it's just a 4x looper. Could the problem be, that I didn't connect all ground cables together in one point?

thx DaKurt