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  #1  
Old 02-18-2013, 09:32 PM
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Homemade preamp issue - won't turn off all the way

recently I converted my MIM Fender Deluxe Jazz V to passive with a VVT control with a push/pull series/parallel switch in the neck pickup volume pot. Everything seems to be working correctly, other than the fact that i still get sound out of it even with all of the knobs turned off. What could the issue be?

Both of the volume pots are 500K and the tone is a 250K

Here's the diagram I followed. Ill put up a picture of the actual wiring shortly.
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  #2  
Old 02-18-2013, 09:47 PM
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Your pots are not grounded properly.
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Old 02-18-2013, 09:59 PM
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How do I properly ground them? They are all grounded to the bottom of the pot as pictured.
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Old 02-18-2013, 10:12 PM
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Did you bend up the one leg of the volume pots and solder them as shown?
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Old 02-18-2013, 10:51 PM
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Where is the homemade preamp? It's a passive bass. There is no preamp.

But as the others have said, your volume pots are not grounded.
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  #6  
Old 02-19-2013, 02:06 PM
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Quote:
Originally Posted by seanm View Post
Did you bend up the one leg of the volume pots and solder them as shown?
I did as best as I could. The solder wasn't wanting to bond with the bottom of the pots. It was kind of a botch job, so I'm thinking about rewiring it to make sure I have solid connections.
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Old 02-19-2013, 02:12 PM
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David Schwab

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Quote:
Originally Posted by Cougmeister View Post
I did as best as I could. The solder wasn't wanting to bond with the bottom of the pots. It was kind of a botch job, so I'm thinking about rewiring it to make sure I have solid connections.
Some pots are plated, so you have to scratch the metal up a bit.

If you can't get the solder to stick, just run a wire from the tab that's supposed to go to ground, and ground it to the output jack along with the other grounds. Then solder your pickup grounds to that tab on the pot.
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  #8  
Old 02-19-2013, 03:01 PM
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Ok, got it fixed, but I still have some hum going on, but it quits when I touch anything metal on the bass. Could this be a poor bridge ground connection?
It's all unsheilded by the way.
  #9  
Old 02-19-2013, 03:08 PM
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David Schwab

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Quote:
Originally Posted by Cougmeister View Post
Ok, got it fixed, but I still have some hum going on, but it quits when I touch anything metal on the bass. Could this be a poor bridge ground connection?
It's all unsheilded by the way.
If it stops when you touch the strings, then the string ground at the bridge is fine.

It could be the lack of shielding, and/or a bad ground connection where the amp is plugged into the wall.
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Old 02-19-2013, 03:14 PM
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Originally Posted by SGD Lutherie View Post
If it stops when you touch the strings, then the string ground at the bridge is fine.

It could be the lack of shielding, and/or a bad ground connection where the amp is plugged into the wall.
Ok. The power strip I'm plugged into says that the wall plug isn't grounded.
  #11  
Old 02-19-2013, 03:31 PM
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Quote:
Originally Posted by Cougmeister View Post
Ok. The power strip I'm plugged into says that the wall plug isn't grounded.
That's probably it.
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  #12  
Old 02-19-2013, 03:49 PM
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That's probably it.
Good. Thanks for the help!
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