single volume pot - mystery

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Pcruis1
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single volume pot - mystery

Post by Pcruis1 » Wed Oct 02, 2019 10:04 am

So.... I tried to build a guitar last weekend. I decided since I had never done any routing before, I would do a single hum with a single volume pot, to try to eliminate potential mistakes. I got a 500 pot from Fender, and had an old 59 hum that I put in the bridge position. The wiring on the 59 was a metal wrap around a single wire. I solder the metal wrap to the back of the pot, and then run the middle wire to hot tab (tab No. 1). There was a two prong thingamabobber that came with the pot, so I took that from the third tab and grounded it to the back of the pot. Middle tab is the hot from the input jack. Basically, I wired it how I assume EVK did his single back in the day.
I plug it in to my Vox AC15 and it works! Though the volume seems to go from 10 to 0 very quickly. No biggie, I think. But then it gets weird. I run it through my orange head last night on heavy distortion.... it cuts the volume a slight bit, but never turns volume completely off. Instead, the volume cuts a fair bit from 0 to 10, but seems to be acting like a tone pot.
Any clue as to what is going on? Is the thingamobber not mean to connect the third tab to ground when wired as a volume pot? I'll try to post some pics tonight of the wiring when I get home.
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Pcruis1
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Re: single volume pot - mystery

Post by Pcruis1 » Wed Oct 02, 2019 11:11 am

I think I just figured it out. I guess that tab is some sort of tone capacitor that I should not be using on a volume pot! I have to admit that the effect it has on my sound is pretty cool, but I need my volume pot to act like a volume pot.
1981 Pacer Strat Head White
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1981 Pacer Strat Head Sunburst
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83/86 Mutt Pacer - TransRed Beak
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Dirty D
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Re: single volume pot - mystery

Post by Dirty D » Wed Oct 02, 2019 11:57 pm

Also make sure it's the correct type of 500K pot (audio taper versus linear taper).
Let us know when you get it sorted out.
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Pcruis1
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Re: single volume pot - mystery

Post by Pcruis1 » Thu Oct 03, 2019 3:51 pm

Dirty D wrote:
Wed Oct 02, 2019 11:57 pm
Also make sure it's the correct type of 500K pot (audio taper versus linear taper).
Let us know when you get it sorted out.
Thanks D. I clipped the tab off last night and soldered it correctly. The taper still seems a little off to me. The volume goes from 10 to 0 when I go from 10 to 5 on the knob. Regardless, I'm done messing with it for a while. It plays, so for my first build involving more than just putting together parts, I am pleased.
1981 Pacer Strat Head White
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AAEA
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Re: single volume pot - mystery

Post by AAEA » Sat Oct 05, 2019 2:23 pm

this is what they used.

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Dirty D
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Re: single volume pot - mystery

Post by Dirty D » Sat Oct 05, 2019 4:22 pm

I've seen some set up with that capacitor, but more often I've seen them come factory with the .022 cap for a single hum/single volume configuration. If you've set it up with no cap and you like it, then great! If you think it sounds too shrill, then that would be a reason to consider putting a cap back in. The cap is like a parasitic filter that sucks off certain portions of the frequency spectrum when you introduce it into the signal path. You can wire it to be in the signal path all the time, or you can put it behind a potentiometer so there is no filter when the pot is closed, and the filter gets introduced gradually as you open up the pot (this is how a typical tone pot works), but it's also possible to put your cap on the volume pot so the tone filter varies at the same time as the volume adjustment.

I hear you about sometimes just wanting to be done with it, but if you decide to go back in, you might try a different pot while you're in there just to see if your taper issue comes out any differently.

Congrats on your success, though! I'm still pretty novice with electronics, but Menace and some of the other guys on here know a bunch about it.

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SO many projects, so little time!

Classic II red Tele
a few other sweet ones!!
some lumies & Spectors
buncha projects that'll eventually get done
some that won't
Bastards:
Ed Sheeran Sig Martin, 1st ed.
Billie Joe Armstrong Gibson LP Jr, 1st year

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Re: single volume pot - mystery

Post by OneInTheChamber » Sun Oct 06, 2019 1:22 pm

great and wonderfully simplified answer to this electronics question.
The often recommended .022 cap for a single hum/single volume situation is subjective and varies a lot especially live at high volume levels out of like Marshalls. My old guitar tech taught me some stuff.
He explained that single hot humbucker and a 500K volume pot can use a little experimentation using a treble bleed situation. heres a treble bleed explaination..https://www.fender.com/articles/tech-ta ... 20control.

but I get sparkling cleans in my one humbucker one volume pot guitars achieving a well balance EQ using a single Duncan HB and rolling back the volume just below 1/2 turn when the right treble bleed using the right capacitor coupled with a resistor & matched/taylored the potentiometer and pickup all together. And it doesn't effect the full volume high power crunch of your humbucker.



Dirty D wrote:
Sat Oct 05, 2019 4:22 pm
I've seen some set up with that capacitor, but more often I've seen them come factory with the .022 cap for a single hum/single volume configuration. If you've set it up with no cap and you like it, then great! If you think it sounds too shrill, then that would be a reason to consider putting a cap back in. The cap is like a parasitic filter that sucks off certain portions of the frequency spectrum when you introduce it into the signal path. You can wire it to be in the signal path all the time, or you can put it behind a potentiometer so there is no filter when the pot is closed, and the filter gets introduced gradually as you open up the pot (this is how a typical tone pot works), but it's also possible to put your cap on the volume pot so the tone filter varies at the same time as the volume adjustment.

I hear you about sometimes just wanting to be done with it, but if you decide to go back in, you might try a different pot while you're in there just to see if your taper issue comes out any differently.

Congrats on your success, though! I'm still pretty novice with electronics, but Menace and some of the other guys on here know a bunch about it.

Image

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Re: single volume pot - mystery

Post by Pcruis1 » Mon Oct 07, 2019 9:57 am

Great information guys - Thanks! I played the new guitar for a while with a drummer this weekend. I am pleased to report the sound/tone is pretty cool. Kind of a dirty and raw blues/rock tone - Black Pistol Fire comes to mind. The only real issue at this point is I must have been off by an 1/8 of an inch in setting the bridge (1/8 short unfortunately) because the low E and A are a little sharp at 12th fret on intonation. I can live with it. Next time, I'll be more careful on the scale length! Here is a picture pre-set up:
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83/86 Mutt Pacer - TransRed Beak
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_xxx_
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Re: single volume pot - mystery

Post by _xxx_ » Mon Oct 07, 2019 11:43 am

It's a rough solution, but if you can't move the bridge, you may be able to move the neck. You may need to file the neck pocket a bit if it's not wide enough and 1/8 shouldn't be visible with the fretboard overhang.

Edit - duh, just noticed it's a 21-fret neck... not so easy there unfortunately.

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Pcruis1
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Re: single volume pot - mystery

Post by Pcruis1 » Mon Oct 07, 2019 2:27 pm

_xxx_ wrote:
Mon Oct 07, 2019 11:43 am
It's a rough solution, but if you can't move the bridge, you may be able to move the neck. You may need to file the neck pocket a bit if it's not wide enough and 1/8 shouldn't be visible with the fretboard overhang.

Edit - duh, just noticed it's a 21-fret neck... not so easy there unfortunately.
I may trade out the neck regardless for a 22 fret neck. It was the only tele neck I had laying around, so I went for it.
1981 Pacer Strat Head White
1981 Pacer Strat Head Walnut
1981 Pacer Strat Head Graphic
1981 Pacer Strat Head Sunburst
1982 Pacer Graphic Beak
83/86 Mutt Pacer - TransRed Beak
1984 Pacer Candy Red Hockey

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