Changing from 2 volume knobs to a blend knob

[Claymore]

I converted my passive jazz to VBT (with the ungrounded blend) and realized it wasn't for me. You get far less resolution and its harder to make subtle changes. Switched it back to VVT and forever it will stay BUT both volume knobs should be linear taper. Many people will feel exactly the opposite and there's no right answer. Try it and you can always switch it back.

 

[fhm555]

Blend pot all day. I also have a BB that will someday get switched to vol/blend, but not a priority right now. Whatever difference in level is meaningless, and the convenience of one vol pot FAR outweighs any unnoticeable differences from a vol/vol setup.

Which is why it’s not a good idea to assume everyone likes the same thing you do. I’ve converted VVT to VBT and discovered i prefer VVT.

 

[Aloe]

blend pots are more finicky to turn if you're doing micro-adjustments. like if you want neck PU to be a hair louder than bridge, you're in trouble: you turn the blend pot and if it's too close to the center detent, it will slip back to center.

even a 250 blend pot actually offers you less fine-grained control than two volumes. you actually have only half of pot's rotation to reduce bridge volume (opposed to full turn on volume). but it's a nice tool to quickly do rough changes.

and yes, likely it will sound a bit different, based on many things like blend's pot type, value or if it's grounded or not. this said, I have a bass where I prefer the feel and sound of two volumes and have one where I prefer the blend (a 250 blend takes away some overhelming treble that I'll need to EQ out anyway; on my other bass I just don't have this kind of treble).

 

[JRA]

Can you guys think of any negatives by doing so?

I think it works really well, and gives you some gradations you can't get with a switch.

no negatives for me: all my axes have them as i enjoy having those gradations on the gig/fly. while there may be differences between an active vs. passive blend arrangement, my passive instruments are more useful with them.

i like them so much i'm thinking about using two of them on my P!

per the OP: all of my PJs are passive (but one) and they all use a VBTT configuration = great satisfaction for this player! i hope your experience is the same! good luck with your blend knob!

 

[iiipopes]

The EMG ABC and ABCX are great active balance controls. EMG makes versions that work with passive pickups, active pickups, and their X series pickups. I have the ABC in one bass and the ABCX in another and I get everything talked about above:

infinite blend, because at the middle detent both pickups are full on, with full range of blend so whether a player wants a little or a lot of the other pickup, it is there;
no volume drop from the impedance drop of using a passive blend;
ease of control with only one master volume;
clarity of signal with no tone loss.

The only negative is that one or the other pickup is full on, but that keeps the signal hot enough that noise is kept at or near the nominal spec, depending on the pickups used, at @ -100dB.

 

[Joybass]

I have changed a passive J and a passive PJ from VVT to VBT just last week. And I am very satisfied with the result. I used MN500 blend/balance pots, and wired them UN-grounded(!). In the middle position both pu's face 0 ohms resistance, and when one is blended out it faces 500 kohm. This way the 'double volume pot' objection does not count.

 

[JW56789]

I'd far rather take my chances with somewhat less that optimum electronic performance, as for the life of me, I can NOT get repeatable settings on a Jazz with two volumes. Life is too short . . . . .

 

[Stewie]

That's why I sold my old jazz bass, too many knobs, the complication was killin' me.

 

[Max Bogosity]

I’m thinking of changing mine to just volume, tone and a pickup selector switch. To my ear, the difference among the ‘in between’ tones is inaudibly subtle when playing with a band.

 

[Joybass]

To my ear, the difference among the ‘in between’ tones is inaudibly subtle when playing with a band.

However true this may be, I do prefer the 'J' sound with neck pu 100% and bridge pu 80-90%. Can't do that with a selector switch, alas.

 

[BurtMacklinFBI]

Personally I’ve come to like dual volumes, but I don’t see any particular reason other than personal preference not to use a blend. The blend will make it easier to control your volume on the instrument, which may be an advantage if you like doing that. Go ahead and change it, you can always go back to VV later if you like.

 

[halfwound121]

One tip- to test the wiring without a meter- tap the pickups with a screwdriver to ensure you have them directionally correct and that no volume comes from the “off” pickup when the knob is turned full each way.

 

[EmuBass]

One tip- to test the wiring without a meter- tap the pickups with a screwdriver to ensure you have them directionally correct and that no volume comes from the “off” pickup when the knob is turned full each way.

WOW!!!

 

[LoTone]

I loath blend pots. I much prefer volume pots. To me, volume pots offer more possibilities.

 

[BAG]

The Göldo Balance Pot does what you want only affecting one pick up at the time. Not sure you get that where you are but there might be similar products.

Is that the Balance Pot with Middle Stop or the True Panorama Pot?

 

[cars10]

Is that the Balance Pot with Middle Stop or the True Panorama Pot?

Not sure what that terms mean. Also never used it. Just looked it up once to try but that never happened.
Anyway I understand it is working like this: each pot has some resistance layer close but not up to the middle position. From there it has a conducting layer. That way if the pots are in middle position they are both connected directly to the output. Turn the pot in one direction one of the inputs will be routed over the resistance. The other stays directly connected. Best I can explayn.

 

[Joybass]

Anyway I understand it is working like this: each pot has some resistance layer close but not up to the middle position. From there it has a conducting layer. That way if the pots are in middle position they are both connected directly to the output. Turn the pot in one direction one of the inputs will be routed over the resistance. The other stays directly connected.

This is an accurate description of a balance pot with MN taper (e.g. MN500, MN250, MN100) which is the one you would want.

There is another species of blend pot, with AC tapering, which basically is a double pot, with one track going from 0 to full resistance and the other track going simultaneously from full resistance to 0. In the middle position a loss of volume occurs because both pickups will face a resistance > 0 there. This type of balance pot is the one you do not want.