Ultimate No-load Ungrounded Blend Pot (Pics!)

[walterw]

Hey @walterw, this goes way back to your layout diagram. Why the linear volume pot? Traditional tapers are audio in J basses right? Does this provide a better response to the control?

Yep.

I think j basses had audio pots because all fenders had audio pots, they used the same pot for everything.

Linear volumes will have a smooth sweep from off to full rather than that "kick" right near the top.

Tons and tons of threads about this (I'm in lots of them)

 

[vin97]

Small update: I got a 100kΩ M/N blend pot from here, cut the traces (no-load), sawed off the excess shaft and installed it according to walter's diagram (unground).
As walter suspected, it's right in the sweet spot and offers the optimal blending IMO (I also tested 250K and 50K pots).
Little bonus: The pot is quite robust (compared to the Bourns), making the "no-load mod" much less of a hassle and it fits the standard hole diameter.

 

[Arnel M.]

OK, after some prompting i finally made a diagram of the whole thing, done in my apparently now traditional goofy MS paint style

it also works just fine without cutting the traces, you still get the smooth blending between pickups and you still avoid extra loading loss from the blend pot; the only drawback is that when you're cranked over to one pickup you still get a slight bit of the other, "off" pickup in the mix. (you don't really hear it though)

if you're a player who mostly shades between the two pickups rather than running either one solo, then this will work nicely without cutting the traces on the blend pot.

Hi walterw. will this work with a PJ? Thanks.

 

[walterw]

Hi walterw. will this work with a PJ? Thanks.

sure, any two pickups.

 

[BunchyMutt]

Any chance you could repost direct to TB? I'm only seeing the photo bucket "please update your account.." message.

 

[JayGunn]

Me too!

 

[BunchyMutt]

@walterw

 

[vin97]

 

[walterw]

yeah, g*****n photobucket just erased half the internet; i'll re-do the pics pretty soon.

[edit: TB has pulled off a miracle and fixed it!]

 

[BunchyMutt]

Thanks! That would explain the sudden lack of photos across the board

 

[rhaas]

I just did this mod while installing a set of Area J's in a second-hand MIM Jazz that I recently picked up. Played with some buddies this afternoon and I don't think I'll ever go back to a VVT setup.

Thanks @walterw !

 

[tallboybass]

What a great thread...thanks to all who have responded!

 

[Derry Murbles]

I'm thrilled to have come across this thread as I wade through my PJ build (Low End PJ Build (With Pics!) Complete with Questionable Squier DNA). I'm looking to do the master volume, blend, and master tone set up, however Im having trouble reconciling a couple things in my mind. Keep in mind I'm not an expert- quite the opposite, especially with wiring.

Here is one example- Also I'm aware that I need to really start studying this stuff so I can not only understand what to do when I want to wire something up, but WHY I need to do it to achieve a certain result:

I'm trying to match up your diagram to ones I've seen online (Seymour Duncan above for example) and it's not exactly a replica (not saying it should be- I just really don't know what I'm looking at as far as actual electrical implications of different wiring options, this lug to that lug, this wire to that lug, etc). I see in the above what appears to be an extra wire between the outermost diagonal lugs on the blend pot, an extra wire connection from middle lug of tone pot to jack tip.

What I've read (trying to find the thread) is that there is a standard way to wire up a PJ setup where:

Blend rolled all the way toward neck= 100% Neck
Blend at center/middle position= 50% neck, 50% bridge
Blend rolled all the way toward bridge= 100% bridge.

Instead what I've come across poring through the interwebz and what I'd like to achieve is a set up where the middle/center position on the blend knob yields 100% neck and 100% bridge. Is that even possible or am I making things up?

Lastly, I'm trying to determine the difference between a M/N blend pot and a non M/N blend pot. I can't seem to pin down the difference, if any. I've got an Alpha 250k blend pot on order from Stewmac but no indication of M/N'ness is listed in the product description...

Since the vast majority of the time I'll have the blend pot in the middle, I probably don't need to cut the traces so as to completely isolate one pickup or t'other, but I'd like the option to if the mod is as simple as it seems.

My bigger objective would be the 100% neck and 100% bridge volume at middle position on the blend knob. Does that require special wiring or is that achieved using a standard PJ wiring, whatever that is?

My apologies for my ignorance on the subject and I appreciate any help you lovely folks might be able to lend!

EDIT- Of course about 4 minutes after I post, I find the difference between MN and AC pots- MN gives you the 100% neck and 100% bridge at middle, AC is 50/50... Now to determine if the alpha blend pot I ordered is MN or AC

 

[walterw]

yeah, g*****n photobucket just erased half the internet; i'll re-do the pics pretty soon.

oh well, here's at least three of the pics, showing the cuts and the final wiring:

they reappeared on my computer so i grabbed them and threw them up here!

talkbass has done the impossible and rescued all their photobucket pics! they've literally gone back and fixed a good decade plus of TB posts wrecked by photobucket.

i'll delete these, they're no longer needed.

 

[khutch]

talkbass has done the impossible and rescued all their photobucket pics! they've literally gone back and fixed a good decade plus of TB posts wrecked by photobucket.

One of many reasons why we love TB so!

 

[screefer]

Hello, New member here.
Regarding cutting the traces on the blend pot.....when you cut the traces, where is the knob position? Center detente or either side? I understand the why but am struggling with the how. I have a 250K Alpha blend pot from stew-mac.
Thanks all

 

[khutch]

It can be anywhere really but you don't want it in the way of the cut or close enough to get damaged so center detent is fine, or turned all the way the other way.

 

[screefer]

Thank you very much. I want to employ this scheme on my new Mikro...

 

[screefer]

It can be anywhere really but you don't want it in the way of the cut or close enough to get damaged so center detent is fine, or turned all the way the other way.

So I performed the cuts with a needle file and the top works like this...when looking at the pot knob end up and the two probes on the center and right lugs of the top row, the reading from center detente is SHORT. Turning the knob counter clockwise it reads 0-239 and when it reaches the end OPEN. As I understand this is right?
However on the bottom row now matter where I put the probes, the reading is OPEN no matter where the wiper is. So I took the bottom apart and attached is a pic of the lower wafer.
Where am I going wrong?
Thanks

 

[vin97]

Maybe you damaged the little rotating metal arms.
Happened to me with the Bourns pot, it's not very robust. Did you disassemble the pot to do the mod?