Question about DGT pups...

[The Guitar Surgeon]

Hi,
I have a client who wanted his 2009 DGT modded with the resistors so that it does not have a volume drop when split. I purchased the resistors (1.1Kohm and 2.2Kohm) for each pickup. I wired them in and it works perfectly. Or so I thought. It did the job, but if he has the pups split and the volumes are not "matched," both, say, on 8, he hears a slight hum. If one volume is at 4 and the other is at 8, there's a slight hum. Put them both at 8 and the hum disappears. Is this normal? Is there something I can do to solve the issue? Is it b/c the lower you go on either volume you cancelling some of the hum-cancelling properties?

Thanks for anyone who can answer.

Bob

 

[Boogie]

Hmm…check for errant solder, or that you didn’t get a rosin barrier to ground. I’ve never experienced hum while lowering the volume and I use the splits all the time. Bizarre…

 

[The Guitar Surgeon]

I spoke with one of my amp guru buddies and he said when dialing back the volume, you are knocking out more and more of the coil, so you can get some small amounts of hum b/c the two coils that are split are not RWRP. It makes sense, and was what I was thinking. Essentially you go from humbucker to partial humbucker, reducing the amount of coil used from full to zero before the resistors are put in. With the resistors in place, you essentially run most of the coil to ground, but as you turn down the volume you are getting less of that coil to respond and it becomes more and more a single coil and a little hum is expected. I have never done this mod, and from a theoretical standpoint I'm trying to reconcile what is happening with logic. But I thought I'd ask.

If someone with a DGT with this mod (which came standard after the first year or two) wouldn't mind, plug yours in, turn it up, split the coils, and check all the positions. Then, in with both HB split but on, dial the volume in and out and listen for hum and let me know what you hear. Maybe it's something so minute most people don't notice until they are plugged into headphones or isolated. I just don't know.

I have a 1995 CU22 with McCarty wiring and the split to single coil hums a little, as expected. But I have never done the mod on a split humbucker. I will probably do it to one of my guitars, as I have an old Santana SE with Dragon II's that are wired with McCarty wiring. I just need to add the resistors. I will experiment on it and find out what happens, but I'm interested to see what others say. I hope some more people with a DGT chime in.

Thanks,

Bob

 

[Boogie]

The cleanliness of the electrical environment may be a factor. I played my DGT this past weekend thru the Kemper, with headphones, split with volume down to 6, and had no hum. The Kemper is on a server-class ups with excellent regulation and filtering, plus, my house is unusually free of EMI (RFI is another thing with wifi and stuff). Maybe I’m fortunate but I can’t reproduce your findings.

 

[The Guitar Surgeon]

Ok, so I worked got the guitar back. I checked all solder connections. I contacted PRS and they sent the old and new schematics. It's wired correctly according to them. I plugged my CU22 with McCarty pups into my best tube amp and cranked it. In HB mode, not tapped, touching strings, dead quiet in all 3 positions. Not touching strings, bridge is dead quiet, there's a bit of hum in middle and neck, but it's not properly grounded when not touching the strings. Turned off the lights in the room, much improved.

In tapped mode, touching strings, a little hum in all 3 positions, a little louder in middle and neck. Not touching strings, hums in all 3 positions, louder in neck and middle. Turned off the lights, a little better, but still there. I had to turn up and listen, but it's the normal single coil hum.

Plugged in the DGT I modded with resistors, got the EXACT same results. So, it's just the way it is, I guess. I did it with my Santana SE which has McCarty wiring but Dragon II pups, and exact same thing.

Any other DGT owners? If you plug into a tube amp and test it in the manner above, what do you get, if you care to check?

Thanks, and this guitar belongs to TexSunburst here, he's a great friend. He asked me to do the mod but heard some noise when he got it back. I'm thinking it's the normal noise but just wasn't picked up before. I never noticed my CU22 did it until I tested it tonight, but it's all exactly the same noise.

Thanks, all!

Bob

 

[alantig]

Just tried mine for you. DGT thru a G-System, no FX (one exception, as you’ll see) into my Archon. Tried this three ways - clean channel, lead channel, and clean channel with a Tonebone Hot British pedal (this was the exception). All three modes were essentially the same - HB mode had no perceptible noise in any of the three positions. Tapped mode had a minimal amount of hum/buzz, but nothing that was remotely objectionable. It was more noticeable on the dirty settings, but still quite minimal. The noise was the same across all gheee toggle positions for each of the amp settings (i.e., neck, bridge, both all sounded the same). Hope that helps.

 

[The Guitar Surgeon]

Just tried mine for you. DGT thru a G-System, no FX (one exception, as you’ll see) into my Archon. Tried this three ways - clean channel, lead channel, and clean channel with a Tonebone Hot British pedal (this was the exception). All three modes were essentially the same - HB mode had no perceptible noise in any of the three positions. Tapped mode had a minimal amount of hum/buzz, but nothing that was remotely objectionable. It was more noticeable on the dirty settings, but still quite minimal. The noise was the same across all gheee toggle positions for each of the amp settings (i.e., neck, bridge, both all sounded the same). Hope that helps.

Thanks for your report. I have now tried it on a McCarty and got the exact same sounds as the other 2 guitars. It's all good.

Thanks again, alantig. I appreciate you taking the time.

 

[alantig]

Thanks for your report. I have now tried it on a McCarty and got the exact same sounds as the other 2 guitars. It's all good.

Thanks again, alantig. I appreciate you taking the time.

You’re welcome, sir!