Stew Posted May 9, 2005 Report Share Posted May 9, 2005 (edited) Here's what I have wired, which is exactly what the installation instructions describe in the LR Baggs manual. I've installed about 4 of these in the past and have had no problems......except for this one. I replaced the LR Baggs standard sized 5 meg with a mini 5 meg pot. System is brand new. I have a Fishman Y stereo cable which I've used on my other X-bridge installations to check each signal. The Magnetic signal is fine, strong and free of any hum. This is true when using a usual mono jack when I just want to play magnetic signal only. Now when I switch to the acoustic amp to test the piezo signal, using the stereo Y cable, my gain light is glowing like crazy (you adjust the incoming gain before adjusting the volume. So you adjust the gain until the light goes off which means stop clipping, and then bring up the master volume of the amp). I thought it might be the cable but when I plug the magnetic side of the Y cable into the additional instument jack on the acoustic amp, again magnetic is perfect. So I'm wondering if the tabs on the 5 meg pot (piezo vol/blend pot) might be cancelling the signal due to the contact with the control area, which is painted with shielding paint. I turn off the magnetic volume at the guitar and I hear something trying to happen but nothing as a definite piezo signal. Just bizarre occilation sounds when I'm rotating the piezo volume pot. Plus I get hum when I touch the metal knob on the pot. But then almost all the metal hums when touched. But my magnetic signal does not hum when you touch any of the metal on the guitar. What do you think? After opening link, click on the image to enlarge. http://community.webshots.com/photo/162851...33963910uMdryM# Edited May 9, 2005 by Stew Quote Link to comment Share on other sites More sharing options...
Scott Rosenberger Posted May 9, 2005 Report Share Posted May 9, 2005 try it with the pot not mounted in the guitar and see if it happens Quote Link to comment Share on other sites More sharing options...
psw Posted May 9, 2005 Report Share Posted May 9, 2005 (edited) Well, Stew...this is easy money . Thought I'd help you out by posting your wiring diagram.... And because I'm such a fan here's the beautiful guitar.... Anyway...I don't see where the battery goes but maybe there is some kind of short with the shielding. At least disconect the ground wire. As the piezo system is active there really shouldn't be too much of a need for it noise wise I wouldn't have thought. Otherwise as scott says...perhaps try and test the Baggs out completely separate from any other wiring in the guitar (including any shared ground) and see how you go. good luck pete Edited May 9, 2005 by psw Quote Link to comment Share on other sites More sharing options...
frank falbo Posted May 9, 2005 Report Share Posted May 9, 2005 Do you have a ground wire connecting the 5 meg pot to the other pot's ground? It looks like you just are expecting the connection to the shielding paint to be your ground for the whole LR Baggs setup. Unless the trem itself is somehow bridging the piezo shield together with the tone pot, it seems your magnetic electronics aren't solidly grounded to the output jack anywhere. You mention an extension splice or two there, maybe that's where your trouble is. Quote Link to comment Share on other sites More sharing options...
Stew Posted May 10, 2005 Author Report Share Posted May 10, 2005 frank, So you're saying that what's missing is the last link between the two magnetic linked ground wires and the 5 meg pot? I'll bet that's the problem because I think that's the only thing I've done differently from other X-bridge installations. I'll try that out. Thanks again Pete. And the battery (navigation deck light circuit) is about 2 inches away from where the toggle switches are. It's mounted on the side wall of the control cavity. I made some new green lenses for the light today. The other one looked too blue when lit. I added yellow to the green dye this time and hopefully will look more green in color when turned on. For those who don't know, the deck light is fully functional by a 12 volt battery and a 3 mm LED white bulb inside the housing. I fabricated the light using a pulley casing and casting resin. It's turned on by use of the 2 way slider Jag switch at the chrome plate controls. Quote Link to comment Share on other sites More sharing options...
psw Posted May 10, 2005 Report Share Posted May 10, 2005 Very cute stew...I thought it was a mooring cleat! Hope you have luck with the circuit! pete Quote Link to comment Share on other sites More sharing options...
Stew Posted May 13, 2005 Author Report Share Posted May 13, 2005 Ok, here's what I did: 1. Connected ground wires from both magnetic vol/tone pots to LR Baggs volume pot. 2. Coming from the LR Baggs ground wire chain is another wiring going to the trem claw. 3. LR Baggs pot rotated so that the termianals are no longer touching side of control cavity (shielded). NO PIEZO OUTPUT THROUGH THE Y CABLE INTO MY ACOUSTIC AMP. So I'm thinking that maybe there is a short in the Y cable. I plugged both magnetic and piezo ends of the cable into the SWR California Blonde acoustic amp. At the junction where the two signal cables split at the Y, if I bend the cable at that point, I get a loud hum (or at least my input signal clip light brightens up to steady). The SWR has two channels so I plugged the magnetic into the second channel. I didn't get any magnetic signal, yet when I plug into my Princeton amp with a mono cable, I still get a magnetic signal. Still hum is eliminated when I touch any metal on the magnetic signal. I have a Blackface '65 Princeton Reverb that has a back ground switch and this switch eliminates the hum. But this doesn't solve the problem if I play through my HR Deluxe amp (which has no such ground switch). It's the Y stereo cable right? Quote Link to comment Share on other sites More sharing options...
psw Posted May 14, 2005 Report Share Posted May 14, 2005 Hmmmm...the Y cable is definitly a suspect! I'd be trying to isolate, and get a signal from, the piezo system with a normal lead first. I mean, it could be the battery around the wrong way or some kind of power short...or the things just not working (unlikely, I hope). Once you've established that you can get a piezo signal out, then the troubleshooting may be a bit more straight forward. As I read it, you haven't been able to get a piezo signal at all (except the grounding hum). Here's an aside question stew...on this guitar, the big knob under the trem, is that just the piezo volume or a master. It looks like your mags are controlled only by the roller pots on the Jag plate....is that right? Seems a little inconvieniant IMHO but it certainly looks cool and streamlined. And, have you ever thought of some kind of aeronautical theme to your designs...Maybe not a Cessna but some of those aerobatic type planes have a cool look...just a thought pete Quote Link to comment Share on other sites More sharing options...
Stew Posted May 15, 2005 Author Report Share Posted May 15, 2005 Light circuit is totally isolated from the rest of the circuits and in an insolated harness. Yes, the big knob is the piezo volume. I know, very inconvienient, but this is supposed to be hung on the wall and not played. My next one will not have the piezo circuit but both tones will be at the top chrome plate and the big knob will be the master volume. The magnetic circuit sounds amazing. Quote Link to comment Share on other sites More sharing options...
Stew Posted May 24, 2005 Author Report Share Posted May 24, 2005 Well, got the new LR Baggs stereo Y cable. Plenty of magnetic signal, zero piezo. I'm starting to think my 5 meg pot is dead. No hum or anything coming from the piezo side. Quote Link to comment Share on other sites More sharing options...
Sambo Posted May 24, 2005 Report Share Posted May 24, 2005 Just do it the easy way. Connect the piezo output and ground directly to a normal mono cable and see if there is output, then you can problem solve backwards and exclude pots, wiring/grounding, jacks and cables Quote Link to comment Share on other sites More sharing options...
psw Posted May 24, 2005 Report Share Posted May 24, 2005 I'd be trying to isolate, and get a signal from, the piezo system with a normal lead first. I mean, it could be the battery around the wrong way or some kind of power short...or the things just not working (unlikely, I hope). Once you've established that you can get a piezo signal out, then the troubleshooting may be a bit more straight forward. As I read it, you haven't been able to get a piezo signal at all (except the grounding hum). ← It's the only way isn't it Sambo.... Anyway Stew...how's this going, you got it working yet? pete Quote Link to comment Share on other sites More sharing options...
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