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Replace Blend Pot with VVT

A

allboutbass

Oct 2, 2019
249
271
#1
Hi,

I have this American Elite Precision that I use mostly in passive mode ,it is a blend and volume pot and I am going to remove the preamp and let it just passive. The P pickup is a PV63 and the J is the stock 4 gen noiseless.

These are the stock pot values fender told me:

Volume : 25kA
Passive Tone: 100K, .1uf cap
Blend : 250K

Since I really like the passive tone now, and I am going for V-V-T configuration, I would like to know what pots would get me close to those values. I have no idea how a volume and blend pots total load is

Also, since I have a custom made pickguard already there I was thinking in filling the extra holes left with going VVT, I might put a series parallel switch and a switch for 2 caps with the 0.1uf and .047uf. So I will have a "more modern" tone cut with the .1uf and a more classic cut with the .047uf ... if this make any sense.

I am in doubt if going with 250K on all three pots, or may be 250 on vol pot and 500k on tone pot. I have recently changed a AVRI 75 jazz bass tone pot with a 500k and .047uf cap which suits me better than the original 250K/.022uf

Any thoughts would be of great help
 
#2
I would recommend, based on my own experience, 500k linear for your volumes and 250k audio for your tone. For my taste a 0.1uF cap is far to big - rolled back it just creates a flubby mess. But the result does depend a lot on the impedance of the pickup, so it might work for you.

EDIT: I wouldn't go with a 500k tone pot. All that happens is the control does nothing until you get to the last 1/4 turn - it becomes a switch.

The cap switch is a good idea, but did you know you can actually get 3 settings from 2 caps if you use a DPDT On-On-On 'pickup selector' type switch? The three settings are 'one', 'the other' or 'both'. Here's how I did it on my PJ - Ignore the resistor and greasebucket switch and just imagine the bottom of both caps going straight to ground.

Wiring Diagram.jpg

The switch works like this:
upload_2021-5-10_10-34-6.png
 
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#3
SteveCS said:
I would recommend, based on my own experience, 500k linear for your volumes and 250k audio for your tone. For my taste a 0.1uF cap is far to big - rolled back it just creates a flubby mess. But the result does depend a lot on the impedance of the pickup, so it might work for you.

EDIT: I wouldn't go with a 500k tone pot. All that happens is the control does nothing until you get to the last 1/4 turn - it becomes a switch.

The cap switch is a good idea, but did you know you can actually get 3 settings from 2 caps if you use a DPDT On-On-On 'pickup selector' type switch? The three settings are 'one', 'the other' or 'both'. Here's how I did it on my PJ - Ignore the resistor and greasebucket switch and just imagine the bottom of both caps going straight to ground.

View attachment 4264043
The switch works like this:
View attachment 4264044
Click to expand...
Hey thanks for the 3 position switch idea, I think I might actually go for it.
 
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#4
There is always room for experiments, but here are a couple suggestions for a passive P/J that have done me well in my experiences...
-For maximum flexibility with the P/J, have some sort of series/parallel switch just for the P pickup (I usually use a push/pull tone control for this so I don't have to push/pull volume controls that may or may not be set to a specific spot). This way you can cop a more convincing J type tone with the P pickup in parallel and blended with the bridge pickup.
-If going VVT, linear taper volumes give a wider range of finer adjustment. The value you choose will be based on what you prefer. 250K is the traditional value on Fender basses, 500K will give a little more bite to the tone, which can be rolled back with the tone control or amp setting. I posit that Fender used audio taper 250K pots everywhere to keep the amount of part numbers in stock to a minimum.
-Regardless of the volume pot values, I always up my Fender tone controls to a 500K audio taper. It adds a small touch of air, and it's easily rolled back to around 7 or so to sound just like a 250K pot on 10.
-The 3 way selectable tone cap switch is also a cool idea for getting a lot of tones. Just know that you don't really hear the cap differences until you are pretty deep into the control--like around 4 or lower on it's setting, and the differences are very noticeable from 0-2. The suggestion of a .022uF and .047uF is solid.
 
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#5
bigtone23 said:
There is always room for experiments, but here are a couple suggestions for a passive P/J that have done me well in my experiences...
-For maximum flexibility with the P/J, have some sort of series/parallel switch just for the P pickup (I usually use a push/pull tone control for this so I don't have to push/pull volume controls that may or may not be set to a specific spot). This way you can cop a more convincing J type tone with the P pickup in parallel and blended with the bridge pickup.
-If going VVT, linear taper volumes give a wider range of finer adjustment. The value you choose will be based on what you prefer. 250K is the traditional value on Fender basses, 500K will give a little more bite to the tone, which can be rolled back with the tone control or amp setting. I posit that Fender used audio taper 250K pots everywhere to keep the amount of part numbers in stock to a minimum.
-Regardless of the volume pot values, I always up my Fender tone controls to a 500K audio taper. It adds a small touch of air, and it's easily rolled back to around 7 or so to sound just like a 250K pot on 10.
-The 3 way selectable tone cap switch is also a cool idea for getting a lot of tones. Just know that you don't really hear the cap differences until you are pretty deep into the control--like around 4 or lower on it's setting, and the differences are very noticeable from 0-2. The suggestion of a .022uF and .047uF is solid.
Click to expand...

Yes, I recently did up a Jazz Bass to a 500K tone pot and I think is much better as the open knob has this "air" as you say.
On the series/parallel switch thing, I was thinking for both pickups but now you gave me that idea for the P pickup only, do you have any clip or link for it? ... I have never heard a P pickup in series, this got me really curious.

For me the .022 is actually a bit too honky as the resonance bump is higher but I guess the .047+.022 option is a good idea as I was just thinking only .047 and .1 so I guess having .069/.047/.022 is good enough and sure can make use of the 22 honkyness as it sure has its place.
 

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