Ultimate No-load Ungrounded Blend Pot (Pics!)

[SharpCat]

The more “goo” you add to a passive circuit, the more the pickups get loaded down. My first thought is that you’re unlikely to use this often, and should rethink the utility. But if you want to continue, consider using opamp buffers to isolate the individual VT circuits. It’s a very simple schematic, and you can use one chip to buffer both. You would need to add a battery though.

Other than that, could take a look at Rick-O-Sound. https://www.sweetwater.com/insync/rickenbacker-what-is-rick-o-sound/

 

[jglunt]

I'm looking to wire the two passive pickups on my custom bass build separately with V/T controls with a blend between them. Then output eacj pickup to two mono jacks to 1) send discreet signals from each pickup to two amp inputs and/or two audio interface channels, or 2) join them with an adapter for a mono signal where needed. Any reasons this won't work?

Is there any diagramming for that scenario?

As I understand it, you're going to have a V & T for the neck PU and a separate V &T for the bridge PU. If I'm reading this right, why have a blend control? You'll have separate volumes and can achieve a great blend simply by adjusting them up or down. Just wire each V & T onward to its own separate jack and you're done. I think you could run a jumper between the jacks and put a simple "on / off" switch in it if you need to run both pickups together in a mono jack, but I'd have to think on that a little more. I've re-wired lots of basses, but never like this. Now that you've given me the idea, I have two basses with individual V & T for each PU, so I might try something like this.

 

[Brian Patterson]

As I understand it, you're going to have a V & T for the neck PU and a separate V &T for the bridge PU. If I'm reading this right, why have a blend control? You'll have separate volumes and can achieve a great blend simply by adjusting them up or down. Just wire each V & T onward to its own separate jack and you're done. I think you could run a jumper between the jacks and put a simple "on / off" switch in it if you need to run both pickups together in a mono jack, but I'd have to think on that a little more. I've re-wired lots of basses, but never like this. Now that you've given me the idea, I have two basses with individual V & T for each PU, so I might try something like this.

The idea is to set V/T on each pickup and use the Blend to modulate between them. A 'one-knob' approach during play...if it makes sense.
The whole stereo direction is for recording purposes primarily but also for the dual amp inputs too, obviously.


Any direction on this with a schematic would be apprecizted - don't want to suffer signal loss or attentuation in any way.

 

[Brian Patterson]

The more "goo" you add to a passive circuit, the more the pickups get loaded down. My first thought is that you're unlikely to use this often, and should rethink the utility. But if you want to continue, consider using opamp buffers to isolate the individual VT circuits. It's a very simple schematic, and you can use one chip to buffer both. You would need to add a battery though.

Other than that, could take a look at Rick-O-Sound. https://www.sweetwater.com/insync/rickenbacker-what-is-rick-o-sound/

I found the schematic - I need a component diagram - anybody up to it?

And are those odd pots they spec? 330k?

 

[SharpCat]

I found the schematic - I need a component diagram - anybody up to it?

And are those odd pots they spec? 330k?

View attachment 7199499

Bourns makes a 300k: PDB241-GTR01-304B0

If you wanted to try building this, I’d just use 250k pots. Rics are different just to be ornery.

Before modding a bass, I suggest drilling 7 holes in a small board and wiring it up there, then just run wires from the bass pickups over to it, and try it. Might not sound like you want. Kinda like the stewmac wiring jigs.

Switch and the switched mono jack, need to get input from someone that knows Rics.

 

[Brian Patterson]

I found the schematic - I need a component diagram - anybody up to it?

And are those odd pots they spec? 330k?

View attachment 7199499

Found what
i

was looking for...

Bourns makes a 300k: PDB241-GTR01-304B0

If you wanted to try building this, I'd just use 250k pots. Rics are different just to be ornery.

Before modding a bass, I suggest drilling 7 holes in a small board and wiring it up there, then just run wires from the bass pickups over to it, and try it. Might not sound like you want. Kinda like the stewmac wiring jigs.

Switch and the switched mono jack, need to get input from someone that knows Rics.

Excellent suggestion...I will do that for sure.

 

[SharpCat]

Could just, y’ know, buy a Ric.

 

[Brian Patterson]

Could just, y' know, buy a Ric.

Ha! That's the easy way out...I'll have a few design features that aren't found on 'store bought' instruments.

Looking at those Curtis Novak pickups, among others, for a custom bass I'm building. Pickup selection is excruciatingly difficult...

 

[int]

I'm just stopping in to say thanks to walterw. I had some spare blender pots available and the OP gave me exactly what I was looking for from my partscaster PJ bass. Thank you, Sir!

 

[Cassian Hill]

I'm attempting this mod for the first time, first time swapping out my pickups as well so I'm fairly green. In Walter's original diagram I don't see where the pickup grounds go, I'm assuming the neck PU ground is on top of the master volume pot and the bridge PU ground should go on top of the master tone pot. Or do I not ground them at all? I wanted some more clarification on this before I start this weekend.

 

[SharpCat]

I'm attempting this mod for the first time, first time swapping out my pickups as well so I'm fairly green. In Walter's original diagram I don't see where the pickup grounds go, I'm assuming the neck PU ground is on top of the master volume pot and the bridge PU ground should go on top of the master tone pot. Or do I not ground them at all? I wanted some more clarification on this before I start this weekend.
View attachment 7249961

Grounds all get connected together. The typical thing is for the pickup grounds to get tied to the same pot as the signal, but I don't like soldering to the MN pot side. I recommend using the tone pot back as a dispatch point, and send wires to the master volume pot, bridge, each pickup, and the output jack, and any cavity shielding.

 

[Cassian Hill]

Grounds all get connected together. The typical thing is for the pickup grounds to get tied to the same pot as the signal, but I don't like soldering to the MN pot side. I recommend using the tone pot back as a dispatch point, and send wires to the master volume pot, bridge, each pickup, and the output jack, and any cavity shielding.

Thanks for the advice. As for cutting the traces; can this be done without disassembly of the pot? Most of the videos online of DIY no load pots is with linear pots and they disassemble it before making the cuts.

 

[SharpCat]

Thanks for the advice. As for cutting the traces; can this be done without disassembly of the pot? Most of the videos online of DIY no load pots is with linear pots and they disassemble it before making the cuts.

With the ungrounded blend, trace cutting isn't really needed for the tone or volume, IMHO. But the audio taper and linear pots should look the same, so the videos should still apply.

The MN pot doesn't load the circuit in this configuration (ungrounded) when centered, and being dual-layer is complicated to disassemble.

You can always open it up and cut traces later. Build the rest of the circuit first and see if it sounds good before doing any trace cutting.

 

[Cassian Hill]

With the ungrounded blend, trace cutting isn't really needed for the tone or volume, IMHO. But the audio taper and linear pots should look the same, so the videos should still apply.

The MN pot doesn't load the circuit in this configuration (ungrounded) when centered, and being dual-layer is complicated to disassemble.

You can always open it up and cut traces later. Build the rest of the circuit first and see if it sounds good before doing any trace cutting.

So I removed the ground on the blend pot and now the blend function is reversed, when I go in the direction of the neck PU, it solos the bridge and vice versa. I'm assuming this is a polarity problem. This blend was done by the previous owner, I noticed it lacked some clarity or treble so I thought this mod would address that. Any advice on how to fix the reversed blend direction?

 

[SharpCat]

So I removed the ground on the blend pot and now the blend function is reversed, when I go in the direction of the neck PU, it solos the bridge and vice versa. I'm assuming this is a polarity problem. This blend was done by the previous owner, I noticed it lacked some clarity or treble so I thought this mod would address that. Any advice on how to fix the reversed blend direction?

Pictures always help.

 

[Cassian Hill]

Pictures always help.

Here are some photos.

 

[Cassian Hill]

I haven’t installed the new pickups yet, I wanted to try the unground mod before I install them. They should arrive Monday.

 

[SharpCat]

That looks OK, just swap the two pickup hot leads.

 

[Cassian Hill]

That looks OK, just swap the two pickup hot leads.

On the blend pot?

 

[SharpCat]

On the blend pot?

Yes.