Hum after pickup swap (RGD)

[wallfahrt]

Hi,

after swapping the PUs of my RGD7421 and changing the volume pot to a push/pull type for coil split I've noticed a gentle hum when I'm not touching the guitar (strings, bridge etc). This is independent of the switches' position.

The only thing which I could think of causing this is 2 points for GND connection, one being the pot's housing for the jack plug and the bridge and the other being the p/p housing for the humbuckers - but this is the same component being interconnected by a common housing...

To be honest, I can't remember if there was some noise before, maybe it was already existing.

Any ideas? Thanks in advance!

wallfahrt

 

[Insightibanez]

Had the same problem, sounds like a grounding issue.

 

[guitarneeraj]

Could you post the wiring diagram?

From what your symptoms are, sounds like you've connected the bridge to the circuit ground (therefore, when you touch the strings/bridge the circuit gets grounded through your body). I assume you put in active pickups? If so, you need to disconnect the bridge grounding wire.

 

[wallfahrt]

Hi,

I initially referred to this one:

Guitar Wiring Diagram 2 Humbuckers/3-Way Toggle Switch/1 Volume/0Tone/001

But later on I noticed that there's an error regarding the p/p pinout, the lower 2 pins should both be tied to GND (the lower left pin is connected to the neck's start which is a bug IMO). Corrected this, but still the hum exists.

The pickups I installed are an AN7 for neck and a TZ7 for bridge (-> passives). I resoldered all connections (familiar with that), rechecked the wiring, tested different locations for common GND, no chance to get rid of the hum.

The bridge is connected to GND the same location the pickups' GND is connected to (housing of vol pot / pp-switch) - no GND loops existing.

BR,
wallfahrt

 

[guitarneeraj]

You're right, the lower two pins should be connected to ground.

Have you checked the guitar somewhere other than at your house? Hum can sometimes be caused because the electrical wiring in your house is not properly done.

 

[spadz93]

You're right, the lower two pins should be connected to ground.

Have you checked the guitar somewhere other than at your house? Hum can sometimes be caused because the electrical wiring in your house is not properly done.

this could be the case, especially if all his wiring checks out and it stops humming when he touches the guitar. OP, i'm not too fond of ibanez's switches, but would there be a ground to the switch that you might have missed? also, are you making sure that every pot is being grounded via body? what i do in my guitars is make almost a train of grounds, starting at bridge>pot 1>pot 2>(if applicable)pot 3>switch>jack. also, make sure the 3rd prong on each pot is grounded to the body of the pot itself.

 

[wallfahrt]

Thanks for the ideas...again invested an hour or two to get rid of the hum, but no chance...switched back to the original pot w/o pushpull for some other reason (killed the p/p ), resoldered all wires incl. the plug, improved contact to the gibraltar bridge - no help.
The guitar has a simple setup, 2 humbuckers, a 3way switch and the vol pot - the switch has no gnd connection - where should I connect to, housing?
The last thing I could think of would be a proper shielding of the cavities, there's still the original graphite in it which isn't made properly imo.

Are there any other users owning a new RGD7421 who could check whether there is some annoying noise existing?


Posted from Sevenstring.org App for Android

 

[wallfahrt]

another thought...does the orientation of both pickups also have effect on noise, e.g. due to degrading hum cancelling effect? The screw poles for both pickups are located towards the bridge...

 

[guitarneeraj]

The guitar has a simple setup, 2 humbuckers, a 3way switch and the vol pot - the switch has no gnd connection - where should I connect to, housing?

Posted from Sevenstring.org App for Android

Hey dude, which 3 way switch are you using? [Picture??] Generally speaking, if it doesn't have a specific ground terminal, you shouldn't need to connect the housing to ground.

 

[flypap3r]

Have you shielded the cavities? (i.e. shielding paint or copper tape)

 

[wallfahrt]

the switch is the original one 3-way w/o any gnd tab, so it seems to be ok. The cavity is shielded with paint (Ibanez factory made) but I'm thinking of putting in some copper foil as I did it with my other guitars.

Ok, just tested it quickly in another setup...normally I tested with a Zoom G2nu and headphones, supplied via a wall adapter. Noise with the RGD, no noise with my good ol' RG550 (TZ, HfH). Now I put in some batteries for supply - no noise! So the RGD seems to dislike if the FX is supplied from the wall outlet...

Is there any cure for that?

 

[guitarneeraj]

Just a thought, but is it possible you have reversed the polarity on the output jack??

 

[wallfahrt]

no, that's ok so far

 

[guitarneeraj]

It's weird that your RG550 doesn't have this hum and the RGD does... I can't seem to diagnose a consistent issue here..

 

[Whammy]

another thought...does the orientation of both pickups also have effect on noise, e.g. due to degrading hum cancelling effect? The screw poles for both pickups are located towards the bridge...

I didn't see anyone answer this question.

The screws for the Air Norton pickup should face the neck and the screws for the Tone Zone should face the bridge.

This is considered the standard way to set them up and should maximize hum cancellation in split coil mode when using both pickups.

I'm stating the obvious here and I'm sure you know this but I'll say it anyways, just to rule it out.
Using either pickup separately in single coil mode will produce hum as only one coil is being used and no other coil is present to cancel it out.

 

[wallfahrt]

Guys,

thanks for the good ideas, everything helped in analyzing. Just checked out some more things and noticed that exchanging the crappy Zoom wall adapter also helps in minimizing the noise to a level which is really ok...
My other guitar, a Korean LP look-a-like seems to create a similar noise floor as the RGD does - the 550 still rules

So the conclusion is: what would be rock'n'roll without some guitar noise

br
wallfahrt