picking up radio
- ubertar
- ears didn't survive the freeze
- Posts: 3779
- Joined: Wed Feb 18, 2004 7:20 pm
- Location: mid-Atlantic US
- Contact:
picking up radio
I made a polyphonic fuzz that I love the sound of... I'm using it on my movable fretted, five-stringed (two double courses, one single), bowed/plucked thingamabob.
The problem is, it picks up radio. Even worse, it's Disney radio. So I'll be playing some evil-sounding 13 equal metal, and in the pauses, it's "players gonna play play play play play... haters gonna hate hate hate hate hate...". Clearly this is untenable.
I've tried running the wires that go to the output jack through and around a ferrite cylinder a bunch of times to make a toroid, but that didn't help. I don't know what else to do.
The problem is, it picks up radio. Even worse, it's Disney radio. So I'll be playing some evil-sounding 13 equal metal, and in the pauses, it's "players gonna play play play play play... haters gonna hate hate hate hate hate...". Clearly this is untenable.
I've tried running the wires that go to the output jack through and around a ferrite cylinder a bunch of times to make a toroid, but that didn't help. I don't know what else to do.
- DrummerMan
- george martin
- Posts: 1436
- Joined: Thu Jun 05, 2008 12:18 pm
- Location: Los Angeles
- Contact:
i recently had a hawaiian slide guitar's pickup-pzm combo latch ontu what i believe was an 8.5k tone emitting from the building's alarm system three rooms away... maddening.....it was slightly mitigated by lifting the guitar over his head...not fair.. count me curious.
"There is nothing in a caterpillar that tells you it's going to be a butterfly."
R. Buckminster Fuller
R. Buckminster Fuller
-
- mixes from purgatory
- Posts: 2750
- Joined: Thu Jul 03, 2003 11:26 pm
- Location: Denver, CO
- Contact:
Two things come to mind to check/try:
First, go through the shielding and grounding and verify everything is solid and well-connected, from the guitar to the pedal to the amp, and on through to the outlet, mains panel and ground rod. If the ground were questionable at some stage therein, then it's possible that RF can't find the proper path to ground, so it's using the signal lines rather than the ground.
Last time I was demodulating FM, it was a node in a preamp circuit that should have been grounded, but wasn't. Once I found it, it was an easy fix.
The other thing to consider would be mirroring the small output shunt cap at the input. RG Keen explains it fairly well here:
http://geofex.com/circuits/what_are_all ... ts_for.htm
Ideally, the resistor and cap would be physically close to the input jack. Any run of wire that hasn't been treated thusly can become an antenna that re-radiates within the enclosure...a version of Muncy's "pin 1 problem."
The heart of a fuzz is a super-high-gain amplifier. If even a trace of RF finds its way in, it can amplify it into the audible range. The best cure is to keep the RF out to begin with.
Where were you putting the toroids? In the fuzz or the instrument?
First, go through the shielding and grounding and verify everything is solid and well-connected, from the guitar to the pedal to the amp, and on through to the outlet, mains panel and ground rod. If the ground were questionable at some stage therein, then it's possible that RF can't find the proper path to ground, so it's using the signal lines rather than the ground.
Last time I was demodulating FM, it was a node in a preamp circuit that should have been grounded, but wasn't. Once I found it, it was an easy fix.
The other thing to consider would be mirroring the small output shunt cap at the input. RG Keen explains it fairly well here:
http://geofex.com/circuits/what_are_all ... ts_for.htm
Ideally, the resistor and cap would be physically close to the input jack. Any run of wire that hasn't been treated thusly can become an antenna that re-radiates within the enclosure...a version of Muncy's "pin 1 problem."
The heart of a fuzz is a super-high-gain amplifier. If even a trace of RF finds its way in, it can amplify it into the audible range. The best cure is to keep the RF out to begin with.
Where were you putting the toroids? In the fuzz or the instrument?
"What fer?"
"Cat fur, to make kitten britches."
"Cat fur, to make kitten britches."
i've used a ferrite bead (rather than donut) at input and output, tied to a small value cap to ground on the way to/from the circuit. works well in fuzz and boost pedals.
if i'm understanding right, you've got parallel fuzz stages, and a single stage doesn't do this? if so i'd suspect something in the split/sum schemes, and input before output.
if i'm understanding right, you've got parallel fuzz stages, and a single stage doesn't do this? if so i'd suspect something in the split/sum schemes, and input before output.
Village Idiot.
- Snarl 12/8
- cryogenically thawing
- Posts: 3511
- Joined: Sat Dec 20, 2008 5:01 pm
- Location: Right Cheer
- Contact:
- casey campbell
- buyin' a studio
- Posts: 927
- Joined: Wed Sep 17, 2008 11:21 am
- Location: hammond, louisiana
sorry if this has been answered already, but is the box metal or is the box well shielded?
also, make sure you are using good cable connecting the fuzz to the thingamabob.
also, what are you powering your fuzz with?
another thought, could it be that your stringed thingamabob is the antenna? perhaps that is your source of RF?
also, make sure you are using good cable connecting the fuzz to the thingamabob.
also, what are you powering your fuzz with?
another thought, could it be that your stringed thingamabob is the antenna? perhaps that is your source of RF?
- ubertar
- ears didn't survive the freeze
- Posts: 3779
- Joined: Wed Feb 18, 2004 7:20 pm
- Location: mid-Atlantic US
- Contact:
The box is metal. It's powered by battery. The instrument doesn't pick up radio without the fuzz. The mono version of the fuzz picked up radio with other instruments until I added a low pass on the output. With different amps, the problem is the same. The cable is good quality and doesn't have this problem in other situations. It's the fuzz.
Adding a low pass on the summed output in addition to the low passes that were already there on each fuzz's output has helped some. I'll try adding one to the input and see if that helps. Ferrite beads around the low-pass caps sound like a good idea too.
I was putting the toroids in the fuzz, around the output wires of each fuzz circuit, before the output transformer.
Adding a low pass on the summed output in addition to the low passes that were already there on each fuzz's output has helped some. I'll try adding one to the input and see if that helps. Ferrite beads around the low-pass caps sound like a good idea too.
I was putting the toroids in the fuzz, around the output wires of each fuzz circuit, before the output transformer.
Who is online
Users browsing this forum: No registered users and 191 guests