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Picking AM radio signals on my Fisher Space Expander

Posted: Fri Mar 13, 2009 5:12 pm
by jakesta the gangsta
Ok...why am I picking up radio frequencies from the AM seems that the spring tank is acting as an antenna. Does anyone have an idea why this would happen? Has this happened to anyone? Any troubleshooting help?

BTW I built the volume control remote myself based on the schematics of the potentiometer here: ... .php?t=234.

I was wondering if that had anything to do with the AM radio frequencies being picked up...the remote pot works fine. I plug it in and then when I switch it to reverb, the AM frequencies begin and I can raise the volume. However, I don't get a reverb my tank bad?


jakesta da gangsta

Posted: Sat Mar 14, 2009 9:56 pm
by interruptor
That's a tricky one for me.
I also had problems with noise being picked up depending on the position of the spring tank. So often before recording I try different tank positions to find one with less noise. Also the noise raises when I increase the signal level on the remote pot. However if you have no reverb signal at all, only AM frequencies you either have some damage in the amplifier or the unit is not properly set up. There are actually different ways of doing this so it's really worth it to read through the user manual. If you don't have one yourself you can read it online right here.

Picking AM radio signals on my Fisher Space Expander

Posted: Sun Mar 15, 2009 5:01 pm
by jakesta the gangsta
I opened up the tubed unit and it is super clean. But I wonder if something did go wrong, how would I know? I don't see any smoked out spots or anything that looked to have been burned out... Also, I use RCA red and white cabling to hook everything up is that wrong? I don't have the original cabling that came with it. As far as connecting it...I assumed its pretty straight forward.
INPUT coming from instrument cable split L and R as A and B and

OUTPUT of device A and B split as L and R.

OUTPUT of Spring tank to OUTPUT of Tube Device.

INPUT of Spring to INPUT of Tube.

Would I still pick up the noise if the tank was bad? What type of sounds are supposed to emit from it when you switch it to center? I have noticed positioning changes work, but still no reverb...The reverb is painfully obvious correct?

Thanks for the reply