Buzzing with CLF Research Doheny V12

[krskrft]

I recently picked up the Doheny V12 and absolutely love it. However, I've noticed that it tends to growl like crazy when I'm not touching any metal parts. I removed the pickguard and noticed that the cavities seem to have shielding paint in them, and that there's also a metal plate on the part of the pickguard with the control knobs, though the majority of the guard is unshielded. Obviously, some amount of shielding was attempted in the production process. That being the case, is it supposed to make this much noise? I don't have this problem with any of my other instruments (Fender Tele, Strat, and P-Bass, all American models), so I'm fairly certain it's a shielding issue. I kind of figured for a USA-made guitar this expensive, it would at least be as quiet from the factory as the other guitars I own.

[Craig]

I recently picked up the Doheny V12 and absolutely love it. However, I've noticed that it tends to growl like crazy when I'm not touching any metal parts. I removed the pickguard and noticed that the cavities seem to have shielding paint in them, and that there's also a metal plate on the part of the pickguard with the control knobs, though the majority of the guard is unshielded. Obviously, some amount of shielding was attempted in the production process. That being the case, is it supposed to make this much noise? I don't have this problem with any of my other instruments (Fender Tele, Strat, and P-Bass, all American models), so I'm fairly certain it's a shielding issue. I kind of figured for a USA-made guitar this expensive, it would at least be as quiet from the factory as the other guitars I own.

Check out this post: Doheny Ground Issues?

Hope this helps.

[krskrft]

Thanks for the reply. I always thought grounding issues would become apparent via buzzing when you placed your hands on the strings, not when you removed them. I checked yesterday for the telltale issue of the grounding wire not being attached to the tremolo claw, but that seemed to be intact.

Anyway, I ordered a multimeter in preparation for possibly having to add more shielding to the guitar myself. Is it enough to check for continuity between the jack plate and the tremolo claw, or are there any other places I need to check to isolate/clear grounding as the issue? I'm not incredibly savvy when it comes to circuitry, and the V12 has a lot of it!

[Tooslowhand]

If the guitar is new, you could always contact the dealer if you think there is an issue with it. The V12 has humbucking and single coil modes for the pickups. Does the noise happen in both pickup modes or with both pickups selected when in single coil mode? It is unlikely for humbucking pickups to suffer from noise pickup so if you get noise in all modes your issue is most likely grounding. Try it with a different guitar cord to see if it goes away. If not check the grounding of the instrument. The shield wires from the pickups, as well as the bridge ground, pickguard shield plate, and all potentiometer cases should come to a single ground point. That could be a grounding ring in the cavity, or the case back of the potentiometers. Check that all solder joints look good and use an ohm meter to verify zero impedance at those connections. The shielding paint in the cavity needs to be grounded as well and this is usually accomplished by a potentiometer case touching the paint, so make sure there is a good mechanical connection there.

If the noise only happens when using one pickup in single coil mode then you likely have a conducted noise emission problem. The shielding and proper grounding should be taking care of this as well. If not, check the grounding as above, and you could consider improving the cavity shield with copper foil. However it could be things in your house as well. Does it happen with only this guitar? Have you tried other electrical circuits in other rooms of your house? I had a vintage Fender Deluxe amp serviced by a well respected technician. When I got it back I could not use it with any single coil guitars in my house. It hummed like crazy. I figured that the technician had screwed something up but he swore it was dead quiet in his shop. I took it to the studio to try it and it was indeed dead quiet there, but in my house I could only use it with humbucker equipped guitars. I bought a field strength meter and checked the RF noise level in the house. It was pretty high. I turned off the Wifi; no improvement. I turned off all the lights in the house; no improvement. I went to a different room at the far end of the house and it was better but still noisy. I put the amp away and considered selling it. About two years later I replaced all the CFL recessed lights and dimmers in the house with LED kits and different dimmers. A while later I took the old Fender amp out again and tried it. Dead silent. Soooo.... the issue was environmental caused by the CFL lights and associated dimmers. After it had been refurbished, the amp was probably much more sensitive with all the new electrolytic capacitors and new bias resistors. So sorry for the long diatribe, but hopefully something here helps you out. Good luck.

[Craig]

Also, see this post from Paul Gagon: Re: Shielding Test?.

Hope this helps.

[krskrft]

As far as I can tell, the buzzing happens in all pickup positions. It was actually one of the first things I tested upon hearing the noise. It was just as bad in series mode as in any other mode. When I popped open the pickguard, I noticed that the apparent shielding paint work in the cavities was kind of slapdash. I could see unpainted wood in areas. Also, the black paint was glossy. Is that supposed to be the case? Every time I’ve seen shielding paint, it looks matte. My biggest suspicion is that the shielding paint (a) is likely not continuous even in relation to itself, and (b) that it isn’t making contact with the metal plate on the control portion of the pickguard, and therefore is not running to ground. My guess is that it’s effectively doing nothing at this point. If so, I guess I’ll go ahead and shield the pickguard and cavities more completely.

The Doheny V12 is a fantastic guitar. It just gets tiresome having an annoying buzz interject if you aren’t able to perfectly execute every chord change without losing finger contact with the strings or bridge.

[Craig]

If you bought the guitar new from an authorized G&L dealer, you have a 10 year manufacturer's warranty.
Contact the G&L Dealer you got the guitar from to start the warranty repair process.

Please keep us informed about how it goes.

[krskrft]

I contacted G&L support directly earlier this afternoon and talked with Memo on the phone. Seems like we're going to escalate it to a warranty/support case.

[Tooslowhand]

Glad to hear they are looking into it. As for your other questions, I have never seen glossy shielding paint, so it is unlikely that the paint you found in the control cavity is for shielding. In my experience I have not seen environmentally caused noise issues with humbucking pickups so I suspect there is something wrong with the guitar. Good luck.

[krskrft]

Update: I gave the guitar one last play before resolving to send it in for repairs. Lo and behold, suddenly it is not growling like it did before when not touching metal parts. The only explanation I can come up with is that removing the pickguard before helped make some connection with the shielding that wasn’t previously being made. In any case, there seems to be no repair needed anymore. Good stuff!

[Tooslowhand]

More likely to be a bad ground or intermittent connection that resolved itself when you took it apart and put it back together. Possible it will return.