Bmp-1 circuit question

[big kurka]

Hi everyone, so I’ve been trying fiddling with my guitar that I installed a blackout BMP-1 in. I initially had the module’s pot as the bridge vol but found the knob wat to stiff for my liking so I decided to switched it to a master tone control but I can’t get it to work properly, it work more as a on off volume control. My question is does anyone know if the number 1 lug on the pot is permanently grounded? Trying to figure this out before I just snip the pot lug on the pot from the circuit board.
Thanks in advance

 

[Artie]

There's no need to snip anything. Just connect the cap between the "pot signal out" lug and the volume control.

One end of the pot is grounded.
The middle lug is "pot signal out."
The end opposite ground is "pot signal in."

 

[big kurka]

ArtieToo I’ll give that a try, but with the pot connected to ground doesn’t it act more like vol control???

 

[Artie]

No. Look at the tone pot chart I've attached. It's eight different ways to wire a tone pot. All eight are electrically, functionally, and sonically, identical. You would be using method 1, which is the way most LP's, SG's are wired. I use the slightly modified version 5. Other guitars tend to use 3.

I like 5 because if after a few years, you develop a dirty pot, and the wiper loses contact, the tone control goes to "10" rather than removed from the circuit.

 

[Artie]

I can't edit above. The other thing I like about 1 & 5 is, when I wire a guitar, I start by carefully bending back the CCW most tab on all the pots, and soldering it to the case, be it vol or tone. Then just wire each up accordingly to it's function in the guitar.

5 through 8, above, give a slightly more desirable failure mode.

The exception would be if it's a customers guitar who wants to keep everything original.

P.S. Are you doing typical LP 2 Vol/2 tone's?

 

[beaubrummels]

Based on the OPs description, the only thing he would be able to do is version 8, but he'd have to bridge the middle to the outside grounded lug, rather than snip the outside grounded lug.

 

[Artie]

I measured mine on my bench. In the following pic, red is hardwired to ground, green is hardwired to "pot signal out", and blue is hardwired to "pot signal in."

His options are 1 & 5. And if he wants to use 5, he'd jumper "pot in" to "pot out."

 

[big kurka]

Thanks ArtieToo and beaubrummels it makes since now. Some I had myself confused there lol. The guitar has 2 vol 1 tone, although I might change to 1 vol, 1 tone bridge, 1 bass contour neck. Still trying to figure out what I want

 

[big kurka]

ArtieToo Hi Artie Too, so I tried wiring the bmp-1 pot like pot 1 and gave it a try and it doesn’t work. There didn’t seem to be any treble rolloff and when turned all the way down it acts like a on off control. Any thoughts on it. Thanks again

 

[Artie]

Just got home from a DR's appointment. Let me look this over again and see if we can figure out what's going on. The pot should be independent of the rest of the circuit. Let me "ohm" mine out again.

 

[Chistopher]

Might be the wrong value pot if it's acting like a switch

 

[big kurka]

ArtieToo just wanted to let you know I had a wiring mistake causing the issue. Fixed the wiring and it all works perfect now. Thanks for your help

 

[Artie]

Sweet. Glad you got it working.