mikevirok Posted April 23, 2010 Report Share Posted April 23, 2010 Hey all; it's been a while since I've stopped by this forum. I've been really busy with my repairs business and haven't had much time for recreational luthierie in a while. But I'm back!!! Here's my dilemma. I recently purchased an Artec VR2 on-board guitar preamp (it's a variable boost that's not over-the-top). Well, before I install it into a custom build that I'm about to begin, I built a small project box to test it out... When I engage the boost (no guitar hooked up to the cable leading in) and turn the boost up, I begin to hear it pickup AM radio transmissions (think Spinal Tap folks, it's the same issue)... I need to make this stop before I begin the routing job for its installation. If I can't make it act only as a boost and not pickup the radio frequencies, then I can't use it for this project. Now I currently suspect the cause for this is a lack of shielding from outside frequencies. It's mounted in an old Seymour Duncan pickup box for testing purposes only. So, could a good copper-foil shield keep out the frequencies? Virok Quote Link to comment Share on other sites More sharing options...
Ripthorn Posted April 23, 2010 Report Share Posted April 23, 2010 Any grounded shielding will work. Just make sure that it is shielded on all sides and connected to signal ground and you won't have a problem. Quote Link to comment Share on other sites More sharing options...
mikevirok Posted April 23, 2010 Author Report Share Posted April 23, 2010 Any grounded shielding will work. Just make sure that it is shielded on all sides and connected to signal ground and you won't have a problem. I figured as much. Thanks buddy! Quote Link to comment Share on other sites More sharing options...
Tim37 Posted April 23, 2010 Report Share Posted April 23, 2010 idk what will help, i have had a few things pickup radio. 1 amp (when the gain is all the way up luckly i tend to not turn the gain all the way up) a wah pedal and a OD pedal. IDk what it is its all ways the same station ( a conservitive talk radio station.) Quote Link to comment Share on other sites More sharing options...
Samba Pa Ti Posted April 23, 2010 Report Share Posted April 23, 2010 ive heard of this before but never seen it with my own eyes, id love to see a video of a guitar picking up AM radio just for giggles Quote Link to comment Share on other sites More sharing options...
Paul Marossy Posted April 23, 2010 Report Share Posted April 23, 2010 You can usually get rid of RFI by adding a 47pF-100pF cap to ground on the input of the offending circuit. Quote Link to comment Share on other sites More sharing options...
elmo7sharp9 Posted April 23, 2010 Report Share Posted April 23, 2010 You can usually get rid of RFI by adding a 47pF-100pF cap to ground on the input of the offending circuit. Threading the "hot" wire through a small ferrite bead helps, too. Quote Link to comment Share on other sites More sharing options...
WezV Posted April 23, 2010 Report Share Posted April 23, 2010 i get it with a few pedals - generally its in french Quote Link to comment Share on other sites More sharing options...
Tim37 Posted April 23, 2010 Report Share Posted April 23, 2010 ive heard of this before but never seen it with my own eyes, id love to see a video of a guitar picking up AM radio just for giggles mine picks up FM. Quote Link to comment Share on other sites More sharing options...
mikevirok Posted April 24, 2010 Author Report Share Posted April 24, 2010 You can usually get rid of RFI by adding a 47pF-100pF cap to ground on the input of the offending circuit. I'm most likely going to do both: shield the cavity/unit and use the cap. We'll see what occurs. Quote Link to comment Share on other sites More sharing options...
Paul Marossy Posted April 24, 2010 Report Share Posted April 24, 2010 Shielding it will probably do the trick, but there are instances of guitar effects which are shielded picking up radio stations, so I guess also adding that cap would be a good back up measure against it. Let us know what your results are! Quote Link to comment Share on other sites More sharing options...
KeithHowell Posted April 27, 2010 Report Share Posted April 27, 2010 Make sure there are no "dry" solder joints. See my comment above in the "killing pots" thread. Dry joints can have a diode effect and demodulate AM stations. Keith Quote Link to comment Share on other sites More sharing options...
Baazelbub Posted April 28, 2010 Report Share Posted April 28, 2010 But what if i wanted to pickup radio stations, what would i need to do for that. Quote Link to comment Share on other sites More sharing options...
Paul Marossy Posted April 28, 2010 Report Share Posted April 28, 2010 But what if i wanted to pickup radio stations, what would i need to do for that. Maybe you could find a way to build this into your guitar: http://sci-toys.com/scitoys/scitoys/radio/...nute_radio.html Quote Link to comment Share on other sites More sharing options...
Baazelbub Posted April 29, 2010 Report Share Posted April 29, 2010 Maybe you could find a way to build this into your guitar: http://sci-toys.com/scitoys/scitoys/radio/...nute_radio.html Thanks Quote Link to comment Share on other sites More sharing options...
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