Radio through guitar amp

thecolourbox

Picked up my first radio signals through a guitar amp last night, heard about this before but not experienced until now. It was actually quite cool, reminded me a bit of the end bit of I Am The Walrus to be honest, thinking I could use that effect when recording as it sounds cool. Not too concerned (unless I should be of course!) but thought it's always a strange and interesting thing to happen

not_the_dj

One of the techy boffins will be along to explain it, but isn't it down to unshielded cables picking up radio frequencies? I used to get it a lot when I had my first little practice amp and cheapo guitar set-up.

ICBM

It can be due to all sorts of things... badly shielded cables, cold solder joints, loose ground connections etc. Some types of fuzz pedals are particularly prone to it as well, and it can be due to the exact setting of the guitar controls even.

Don't assume that if you can get it by accident you can reproduce it when you want to record something though! Years ago I got a really cool bit of radio interference which fitted the song perfectly when I was demo'ing it using a fuzz pedal, but when it came to record the song properly in a studio, it just would not pick anything up… after messing about with it for ages, we just gave up and I had to borrow a short-wave radio and 'play' the part manually .

EricTheWeary

Only happened to me through Marshall Valvestates - my own and when I've used them in rehearsal rooms.

It is an oddly cool effect though.

Neil

I used to get mini cab chatter quite loudly through my old Marshall master volume tranny amp.

ecc83

Living just a few miles from both Rugby and Daventry transmitters I had all sorts of RFI problems thru' the workshop.

Triode input stages are fairly immune unless some clottish designer decides to do away with the ~50k grid stopper!

Transistor/IC stages were a bloody nightmare! I remember well one Simms-Watt combo that would only shutup after an RF choke LC network on EVERY pin of the chip and a piece of copperclad board stuck over the top of it and grounded 4 ways with 1nFs !

Dave.

thecolourbox

It is a cool effect, especially as it seemed to be a play that was on rather than usual radio chatter nonsense. I was using a large number of pedals (including fuzz) at the time and my "good" patch leads ran out so was using some old crappy ones, so not likely to happen too often I imagine. Were I to try and recreate it I would just record the radio and play with that
Very cool effect though!

DartmoorHedgehog

EricTheWeary said:

Only happened to me through Marshall Valvestates

Mine (AVT 100) used to do it as well - perhaps it's a feature.

A similar thing: my ex-bandmate's Fender Frontman combo somehow used to pick up stuff that people were playing in the next rehearsal room - that was really freaky.

thermionic

My old AC30 used to sometimes pick up Radio 4 (it was a classy amp) clear as a bell. AM not FM though (obviously). It only happened when I had a beat-up Crybaby plugged in - it helps to have some sort of resonant circuit.

I also remember during the illegal CB craze of the early 80s picking up one side of a conversation through my parents' radiogram. The guy speaking was in my year at school!

midlifecrisis

just thinking about it, some poor sod is trying to listen to his radio and all he picks up is someones annoying guitar noodling

marauder

It's not surprising that Fuzz Faces are really bad for radio interference.

This is a simple AM radio receiver, its very similar to a FF.

http://www.electroschematics.com/wp-content/uploads/2008/10/two-transistor-radio.gif

I always run the signal into the board through a 3K3 resistor, with a 470pf cap to ground.

GuyBoden

Add a

marauder said:

It's not surprising that Fuzz Faces are really bad for radio interference.

This is a simple AM radio receiver, its very similar to a FF.

http://www.electroschematics.com/wp-content/uploads/2008/10/two-transistor-radio.gif

I always run the signal into the board through a 3K3 resistor, with a 470pf cap to ground.

Yes I agree, this will create a low pass filter, which won't allow radio frequencies into the signal.

ICBM

marauder said:

It's not surprising that Fuzz Faces are really bad for radio interference.

This is a simple AM radio receiver, its very similar to a FF.

Especially when you realise that a guitar pickup is an inductor (L1) and that the cable capacitance is often in the 500pF range! (C2)

Cirrus

We used to bring a little radio to gigs for an effect in one of our songs. My favourite ever use was at a gig in Evesham where at the end of our set we were getting all atmospheric and jammy, I turned the radio on and it was George Galloway reciting poetry. Surreal!

57Deluxe

I remember the days when I would get Radio 1 (247 on the AM) through my bedroom radiator...

thecolourbox

I found the culprit I think, though it's odd as it wasn't the new fuzz pedal I thought it might have been, and was in fact a pedal I've used quite a lot at home in the past - the Joyo Compressor. Last night it enabled me to not only learn a couple of new songs, but also to catch up on the cricket news.