[tnt1234]

Hi all -

First, let me say thanks to everyone here - this forum is just a fantastic depository for all things OBEL....and it's been immeasurably helpful as I install my first OBEL system....

I fired up the newly installed OBEL, with Waldo buffer and sorted out a few thing....lo and behold, it seems to work! Now, the guitar has no nut yet, and therefore no strings, but when I test the OBEL stereo output, everything is perfect - the guitar is nice and quiet.

But when I switch it to mono, either via the on board switch or the switch in my wheel box (from AO guitars) there is a hum. It's not terrible, but just louder than the OBEL side.

Is this normal?

Of course I checked all my grounds and they look ok - connection to output jack looks good etc....

I will say, I have a crap ton of ground wires, and so have them ground to both the single volume and single tone with a wire connecting those....but both outputs are ground to the volume pot.

Again, it's not a terrible hum, just louder than the OBEL side of things. If this is more or less normal, I'll go ahead and proceed with finishing it up and see how it sounds with strings....

I'll try to post some pics as well....

and thanks.

Walnut body with a little weight relief....




Maple cap, walnut nut....





Looks so neat and tidy before the wires....




Wires everywhere!

[TI4-1009]

Welcome! A couple thoughts-

On both mine with OBEL they're dead quiet with the loop on or off, so it's not "normal".

Looks like you didn't do any shielding- paint or copper foil. But since it's quiet with the OBEL on that might not be it.

Also looks like no copper wire ground bus(s) between the volume pot and the jack. Don't want to reopen the infamous "star ground" issue, but you can sometimes get ground loops going if you're not careful.

Looks like a rotary switch? I've never used one on a guitar (did on an amp) so if that's contributing it's out of my league.

Can you post a large, clear photo of the cavity so we can see the wiring better?

[tnt1234]

thanks for the comments.....

Correct, no shielding....

There is a regular piece of black wire connecting the tone and volume pots. Should I use a piece of copper instead?

I was running out of space on the tone pot, plus my bridge ground wire was a little short and wouldn't reach the tone.

I know star grounding is a hot topic, but I've never had an issue grounding to more than one pot.

I do suspect this is a grounding issue, so plan on taking the jack out and double checking that connection, as well as possibly removing all the grounds on the tone and re-doing them a little more neatly.....

I'll try to post a better pic tonight.

[TI4-1009]

The bus(s) wire was an Irwin thing that was used in Wolf and Tiger and....- some use it, some don't. Here's a photo of my Tiger cavity with the wire going from the volume pot shell to the output jack ground, and all the other grounds soldered to it:



In this case it's a piece of copper wire stripped out of some Romex household wiring, but you can use regular copper strand wire with all or part of the insulation stripped off. I think the main idea is that it's all "linear", the ground can't get running in circles.

If that's the problem...

[tnt1234]

WOW.

That is mind-blowingly neat a tidy.....nice work!

Maybe I'll put that romeo ground in....hmm....really would cut down on the mess if nothing else....

[tnt1234]

Fiddled with the grounds - didn't really do anything other than maybe sit the output jack into the cavity a little more cleanly - and that seemed to do it!

last thing that I can tell for now is, i get more buzz when I touch the rotary switch....which sounds like a ground issue. Am I supposed to ground the switch? Don't really see how....

So close. Have to get the cover to sit right - my finish coats are gumming that up, put in the string through ferrels, get a nut and a fret job....and it will be done....

[softmachine72]

not supposed to have ground wire touch any of the tops of the pots like on a Strat. Kinda, defeats the purpose of using a ground buss.

[tatittle]

Off the top of my head yes absoilutely the switch needs a ground. It will be one of the (at least 2 wires that goes to it. No ground would cause the increased noise you speak of, as touching it turns your entire body into an antanae for noise (vs, a shield when grounded properly). Actually, come to think of it if it is mounted on shielding it would be grounded there too.

An inadequate seating of a jack on metal could cause the issue, similar to above notion.

[tnt1234]

Off the top of my head yes absoilutely the switch needs a ground. It will be one of the (at least 2 wires that goes to it. No ground would cause the increased noise you speak of, as touching it turns your entire body into an antanae for noise (vs, a shield when grounded properly). Actually, come to think of it if it is mounted on shielding it would be grounded there too.

An inadequate seating of a jack on metal could cause the issue, similar to above notion.

I thought the switch gets the hot leads from the pups, and it gets grounded through the pickup's ground. No?


Not sure where I would run ground off this switch.

[tnt1234]

not supposed to have ground wire touch any of the tops of the pots like on a Strat. Kinda, defeats the purpose of using a ground buss.

Hm. I didn't use a bus. I grounded everything per a typical wiring plan. and everything seems nicely grounded, except this switch....

I'm going to check more carefully to see if it's just one setting of the five, which might give a clue, if in fact as I believed, the switch gets it's ground through the pups....

Thanks for all the help so far!



edit - ok - did a quick check before work - issue is the same on all pup settings. When the guitar is in OBEL, it's dead silent. No issue with selector switch. When in regular, feint hum....very slight. If I didn't have the OBEL side to compare it to, might think it's completely normal. Also, discovered that switching from OBEL to normal on the Wheel box produces a loud pop....

Should have some time tonight to fiddle....

[TI4-1009]

I don't think Any of my switches are grounded? I'm trying to think of the wiring for a strat 5-way or a Gibson 3-way, they're both just wired "signal in-signal out", no ground- right? Unless they get grounded by contacting the shielding- if there's shielding, which there's not on stock Fenders or Gibsons.

Wolf had that pull-down resistor from the switch to ground to prevent popping (Blaster related?), Tiger didn't.

[tnt1234]

Boy, it's gonna be hard to get any work done today...

So after a little research, it sounds like I should directly ground my rotary switch. Wondering if I can tap off an 'out' lug on an unused wafer, or if it's supposed to come off something on the used wafer....

Also, I think I should ground my OBEL switch. Again, I guess I could come off the unused middle wafer?

I guess I'm thinking this grounding is for the body of the switches themselves....not the wiring, which then would short out the circuit?

I think. Maybe. I don't know.

All I know is, I'm at work and my guitar is at home, and I really want to finish it up......

[tnt1234]

I don't think Any of my switches are grounded? I'm trying to think of the wiring for a strat 5-way or a Gibson 3-way, they're both just wired "signal in-signal out", no ground- right? Unless they get grounded by contacting the shielding- if there's shielding, which there's not on stock Fenders or Gibsons.

Wolf had that pull-down resistor from the switch to ground to prevent popping (Blaster related?), Tiger didn't.

i think I do see a ground from your switch to your bus.

[milobender]

The switch bodies and the pot bodies ground by being in contact with the shielding (the shielding connected to the buss)... you really need to shield your cavity... If you don't shield your cavity, you'll want to run a ground wire from each body to your buss... which seems like a big pain, shielding fixes that issue, and insures you won't pick up noise in different environments.

[tnt1234]

The switch bodies and the pot bodies ground by being in contact with the shielding (the shielding connected to the buss)... you really need to shield your cavity... If you don't shield your cavity, you'll want to run a ground wire from each body to your buss... which seems like a big pain, shielding fixes that issue, and insures you won't pick up noise in different environments.

How does that happen? The pots/switches connect with the shielding around their holes?

yeah, I'm probably not going to shield at this point. And I don't have a bus. So could I tap off an 'out' lug on an unused wafer on the switch and send that to the back of a pot?