Gibson Chet Atkins Tennessean pickup and wiring saga

[daydreamer]

sorry, try this

http://www.maton.com.au/pdf/whats-new-20101007.pdf

[passfan]

dehughes by crossing your wires you represent a straight reference to ground of 500k for the pickup. That never changes and we know that resistors to ground in a filter network dump the lower frequencies. You happen to like the tone at that resistance really well, right. Now if you wired it properly, that resistance would constantly be changing and the first frequencies being dumped as you turn the volume down would be the lower ones, which you don't like the sound of. This can be compensated for by placing a cap in series across the pot (experiment to find proper value). With the pot wired backwards you are shorting the positive of the cable to the ground. Almost the same as if you pulled the cable and held the end in your hand and touched the tip with your finger. The amp input isn't bothered by the shunt on the input jack at all, but that changes dramatically when you attach a 20 foot antenna to the jack. That's my best shot at the theory of what is happening here.

[dehughes]

Dude....passfan....wow....okay, I'm going to have to re-read that a few times.

Thanks!

[dehughes]

Well, now that I've fixed the hum issue, I'm also wondering if what I'm hearing (and not liking, tonally) is the dual 500k pots in parallel...acting like a de facto 250k pot. I'm wondering if I'd like it better wired up like a 335 (standard Gibson, dual-humbucker wiring).

I've attached original Gibson Chet Atkins schematic. Am I right about the dual volume pots (on my guitar they are now 500k all around) of the pickup volume and master volume essentially, when both turned all the way up, acting like a 250k pot? Might that explain why I prefer the sound of this guitar when I remove the master volume and run it closer to a LP/335 wiring schematic?

[passfan]

Dude....passfan....wow....okay, I'm going to have to re-read that a few times.

Thanks!

Okay, I'm sorry, I got it backwards. Disregard the last part about the cable. If we follow the correct wiring procedure coming off the selector switch whichever pickup is selected is going to see 500k to ground as well as the path to the tone nob off the wiper. That 500k to ground never changes for the pickup even when you drive the wiper to ground the pickup always sees 500k at the mv, and a path to the tone nob. If we swap those two wires at the mv, now when the wiper is turned wide open the pickup will see 500k to ground and a path to the tone nob, but when we turn down the 500k value starts to drop and the tone of the pickup is affected. As well, we are creating a ground loop with the pickup volume control. The tone pot, on the other hand, has had a 500k resistor dropped in series with the cap to ground and our tone is affected here as well. You've highly modified your tone network and created the possibility of a ground loop between the master volume and the pickup volume depending on how the two wipers are set.

[dehughes]

Ah. Let me see if I understand you correctly. You're saying that when I had the master volume wired incorrectly, I had a potential ground loop created between the MV and pickup volume? If so, that makes sense, and would explain what I heard.

[passfan]

And the further down each volume nob went the worse it would get, right?

[dehughes]

And the further down each volume nob went the worse it would get, right?

Yes indeed. Nice. Problem solved, and the book is now closed on my stupid hum problem! Great!

Now, the question remains as to what tone stack I should utilize. Attached are some options. I'm curious as to what the different schematics do to the tone. I'm leaning towards a typical 335/Les Paul wiring schematic, but I'm also considering a two knob setup (single tone, single volume). What do you think? How would these differ from the way the tone pot is wired up on the standard schematic (same as your typical Gretsch master tone pot, as shown in prior attachments)?

THANKS!

[Bananafist]

Not wanting to hijack this thread, but are you selling the original Gibson pickups? I am interested in acquiring a 492R neck pickup, as fitted to this guitar as stock. What price are you looking for?

Thanks

[dehughes]

Sorry...already sold the pickups locally.

On a side note, I rewired this guitar to what is essentially the following:

Pickups -> selector switch -> single volume/tone setup exactly like a '50s wired LP -> output jack. The middle position is sweeeet wired up this way. Not sure about the Seth Lovers I installed in this guitar, though.....I'm leaning towards a preference for A5 magnets, me thinks...

As well, I DO hear the difference with pickups wired to their own 500k volumes vs. pickups sharing a single 500k pot. In the middle position, the high-end comes out with clarity (not harshness) when they share the same pot. On individual pickups settings though, there is no difference (electrically, or acoustically). With each pickup wired to their own 500k volume pot, the highs are somewhat muted...think along the lines of a Cut knob on an Vox.

Also, I still have a slight buzz present when I'm NOT touching the strings. This goes away completely when I touch the strings, so I wager it's a shielding issue, yes? Other than that, it is quiet now and sounds good...