Blend Pot Not Working Properly

[avdekan]

I just finished assembling the bass I'm building at the moment.

All is working as planned accept for the blend pot (stewmac's), which is can select each of the two pickups (100% when fully turned to each side), but it's middle position is dead silent. from the middle position it functions as a volume pot to each side.

I did the standard X wiring for the outer lugs (green is going to the common ground and the pot's body, black is the live wire going to the volume pot), and the two live wires from the pickups are connected to the middle lugs.

There is no contact between the pot/wiring to the copper shielding.

can anyone tell what I'm missing here?

thanks, B

[Donovan]

I just finished assembling the bass I'm building at the moment.

All is working as planned accept for the blend pot (stewmac's), which is can select each of the two pickups (100% when fully turned to each side), but it's middle position is dead silent. from the middle position it functions as a volume pot to each side.

I did the standard X wiring for the outer lugs (green is going to the common ground and the pot's body, black is the live wire going to the volume pot), and the two live wires from the pickups are connected to the middle lugs.

There is no contact between the pot/wiring to the copper shielding.

can anyone tell what I'm missing here?

thanks, B

As wiring colors and schemes vary greatly, it will be easier for someone to help if you can provide a drawing of some sort.

[JohnH]

If its a dual-gang blend pot, where on one half the left lug is ground and the right is hot, and vice-versa on the other half, then a good candidate for the answer is that the ground and hot lugs are the wrong way round. You can try swapping the pickup and ground connections that you have from the inner half of the pot to the outer half, and outer to inner. Keep the diagonal X across the outer lugs.

The thing is, if its what Im thinking of, these pots have 50% of their track (say from left to centre) of very low resistance, and 50% where it builds up the reisistance to change the volume(say right to centre). The inner and outer halves are reversed left to right. So if you wire it right, in the middle position, both pups have a low resistance to hot and a high resistance to ground, and so both work. But if its the wrong way round, then the middle eposition gives both pups a low resistance to ground and high resistance to hot, hence no sound there, which is what you are describing.

John

[avdekan]

If its a dual-gang blend pot, where on one half the left lug is ground and the right is hot, and vice-versa on the other half, then a good candidate for the answer is that the ground and hot lugs are the wrong way round. You can try swapping the pickup and ground connections that you have from the inner half of the pot to the outer half, and outer to inner. Keep the diagonal X across the outer lugs.

The thing is, if its what Im thinking of, these pots have 50% of their track (say from left to centre) of very low resistance, and 50% where it builds up the reisistance to change the volume(say right to centre). The inner and outer halves are reversed left to right. So if you wire it right, in the middle position, both pups have a low resistance to hot and a high resistance to ground, and so both work. But if its the wrong way round, then the middle eposition gives both pups a low resistance to ground and high resistance to hot, hence no sound there, which is what you are describing.

John

I'll try to reverse the wiring today, hope it works.

thanks, B

Edited May 31, 2009 by avdekan

[davee5]

Lemme guess, stewmac pot? They're crap, it has zilch to do with wiring it correctly or not. I had the same issue with 2 different blend pot vendors before I found the one that worked. Basically I looked into it and I seem to recall it having something to do with the stewmac (and other vendors) carrying blend pots that are designed for active setups.

So, if you are looking for a passive blend pot, like the one in my guitar that actually works (finally), try the blend pots from one of three places:

1. guitar parts resource - http://www.guitarpartsresource.com/electrical_blendpots.htm

2. allparts - http://www.allparts.com/store/electronics-...ts,Category.asp

3. guitar electronics - http://www.guitarelectronics.com/category/...nic_parts.pots/

I'm pretty sure all these guys are selling the same stuff, but I can personally vouch for guitar parts resource. I recall other boards saying they are actually the only people that do "true blend," but from photos the other 2 look like they are selling the same product.

Best of luck,

-Dave

[avdekan]

I reversed the wiring (after checking with the multimeter first - which I should have done in the first place) and it all works fine.

thanks for all your help.

B

p.s.

that was the last time I'm wiring a guitar without checking the components first.

lesson learned!

[Mitch]

I had the same problem exactly. Only it didnt end up being okay in the end because i destroyed the pot with the heat from the soldering iron. Whoopsie!