Reducing RI in Breadboard Protos

[skypn]

I'm trying to build a Bazz Fuzz on a breadboard and have perfected a single station Spanish speaking radio receiver. I hear fuzz over it, but right in the mid-range of the pot is the best radio reception. I have cut down all the component leads, to no avail. What are the usual suspects? TIA

[madbean]

A small cermaic cap to ground at the input might help if you don't have one. Also, breadboards can have a bit of their own internal resistance which can be problematic with grounds and esp. if you have multiple BB linked together. Use your DMM to check for resistance b/w the furthest grounding points on your BBs (the furthest spot on the grounding columns, etc). 

Anyway, that may simply be a BB problem and will go away if you put in an enclosure (IOW in a Faraday cage).

[skypn]

First, wow. Thanks for the fast response. I've tried a few different caps at the input, a couple improved reception. I did discover that if I touched the circuit side, pin 1 of the pot the volume of the RI increased. A lot. Maybe if I shorten the patch wires from the pot to the BB? Also on GP l placed an elec gangbox over my BB as a shield. no noticeable improvement. Also, I'm using a 9v batt to power the BB.

[mjg]

It's pretty normal to get more interference if you touch the pots when bread boarding - your body makes an excellent antenna.   

Once you have it in a metal enclosure, the shaft of the pot will be grounded, which will cut the interference. 

[skypn]

I tried grounding the shaft, to no avail.

[Lubdar]

Is the station good at least?

Heh, also if your breadboard is somewhat insulated from the table, i have found that that makes a difference.  I could be wrong though.  My earliest breadboard just sat on my metal and wood workbench and would have a good amount of interference with high gain circuits.  But more recently the breadboards I develop on have some sort of additional metal plate with rubber feet.

It adds and subtracts...

[skypn]

Found my problem. I twisted the wires coming from the pot tighter. Thanks to all for the help