The last (ha!) blend thread

[Cristo]

OK so who am I kidding, I'm sure it won't be the last. And yes, I've searched and read.

Here's the deal:

Blend control for a passive jazz bass - no active, no preamps, etc. Replacing one of the volume controls in a V/V/T setup with a blend, so that I have a continuous range of blending between the tones of the two pickups.

Reading through the threads, I see that:

Some say they prefer the V/V/T setup because they can blend the pickups better than with a blend control!

For me, the volume controls only seem to change the tone for the first few degrees of travel; after that, the sound does not change. The remaining 95% of the control's travel does not change the tone. Is my bass different, or is that how all jazz basses go?

I don't like that very much - that is why the "concept" of a blend control is appealing. I'd like a continuum between the 2 extremes.

However, based on what I read here, some people (apparently different people than the ones above) experience a volume drop when the control is in the center position. Others say that that result is because of an incorrect pot or faulty wiring.

Others say the blend control itself has a narrow range of activity - much like the volume control on my bass - which would defeat the whole reason for installing one!

The question is -

Has anyone installed a passive blending system on a passive jazz bass and gotten it to "work properly" - i.e., blending the output between the two pickups, smoothly, for the full range of control travel, without any volume drops or other irregularities.

Can it be done? Pickup/electronics gurus, have at it.

 

[bongomania]

This thread:
http://www.talkbass.com/forum/showthread.php?t=319211
is still current and going, so you may just want to tag along for the ride.

 

[Cristo]

unity gain buffers...preamps...etc. in that thread.

Doesn't sound like passive bass stuff to me.

Judging by the underwhelming response to this, I'm guessing the answer to my question is "no" !

 

[Baleen]

Not to fan any flames, but I would think it would be easier and cheaper for you to find two single pots with a taper that gets you closer to what you want than it would be to find a double-ganged pot that has the right taper and travel and full volume for both in the center.

Philosophically, the recent threads have reminded me of my contemplation of this puzzle. I have some opinions, all of which have been expressed over various posts. I'm glad people are debating it as this is how things get invented (or not if they don't warrant it)

Practically, my take on this is how often and precisely do I really need to change the settings? I do adjust the pickup balance on my J during a set sometimes, but I move my picking position far more often to affect changes in tone.

And unless I'm recording, little changes in balance are negligible anyway in all but the perfect room with the perfect amps, etc.. Don't mean to cop out with a defeatist attitude, but I don't think I'm missing that much variety in my current sweep from 0-10. ...The law of diminishing returns.

And if I'm recording, I have time to adjust the vols, just so, to make me happy.

All that said, I always position the set screws on my vol and tone knobs so I can reproduce settings I like.

 

[bongomania]

unity gain buffers...preamps...etc. in that thread.
Doesn't sound like passive bass stuff to me.
Judging by the underwhelming response to this, I'm guessing the answer to my question is "no" !

Yeah, that's mostly why I linked you to that thread... in the first post I asked if there was any way to wire passively without the drawbacks you mentioned, and there were zero helpful responses there too. It really does seem as though there is no "higher ground" using the traditional v/v/t or v/b/t setup, aside from using the best grade of components, and the v/v/t setup may help avoid the tapering issues you described in your first post.

 

[Aram]

The question is -

Has anyone installed a passive blending system on a passive jazz bass and gotten it to "work properly" - i.e., blending the output between the two pickups, smoothly, for the full range of control travel, without any volume drops or other irregularities.

Can it be done?

Yes -- I didn't install it myself, my new Nordstrand NJ6 came equipped with a blend. All-passive circuit, not exactly Jazz pickups, but Big Singles are pretty close, and yes, it's a smooth blend with no dropout. I will say that this particular blend may be a little more subtle than on my active basses, but it most assuradly works.

 

[PilbaraBass]

I don't think the question is about whether it works or not...

of course it works...

the question is, can you do a passive blend with a smooth transition both ways, all the way through the range of the blend pot...

To accomplish this, you would require a pot that would do the following

1) when the blend is at centre detente, BOTH pots are at full range...turning the ganged pot more would only decrease one (not increase the other)
2) the taper on the ganged pot would need to be audio (for both, of course)

Then, you'd have a really good change of getting what you want out of a passive blend pot...I haven't been able to find a ganged pot with those specs...anyone?


Personally, I really don't care...because I generally run my P/J (my only two pickup bass) in 3 modes (I use VVT, btw)
1) Series
2) P-bass
3) P/J with the the J-dimed and the P backed off just a smidge...

It's fine TONE control, that I'M after...

 

[bongomania]

Yes -- I didn't install it myself, my new Nordstrand NJ6 came equipped with a blend. All-passive circuit, not exactly Jazz pickups, but Big Singles are pretty close, and yes, it's a smooth blend with no dropout. I will say that this particular blend may be a little more subtle than on my active basses, but it most assuradly works.

Any chance you could pop the lid and give a detailed description (and maybe even a closeup photo) of the parts and circuit used?

 

[Cristo]

2) the taper on the ganged pot would need to be audio (for both, of course)

Hmmmm,

Why would you not want a blend pot to have a linear taper?

I can see the log taper for the volume pot, because you want volume to increase in the nonlinear way that we hear it.

But for the blend pot, I would want the amount of blend to correspond linearly with the knob position.

If the blend knob is set halfway from the center towards the neck, I should get 75% neck, 25% bridge. Wouldn't a log taper pot give me some other value?

Is this why some people have said their blend control does not blend except in the very extremes of the range - because the resistance (and thus the blend) has not changed much until nearly the full travel of the pot?

 

[Aram]

I don't think the question is about whether it works or not...

of course it works...

the question is, can you do a passive blend with a smooth transition both ways, all the way through the range of the blend pot...

And the answer is yes.

Any chance you could pop the lid and give a detailed description (and maybe even a closeup photo) of the parts and circuit used?

My digital camera was recently stolen, but once I get a new one I will post a pic of the cavity for you.

 

[Jazz Ad]

I don't think the question is about whether it works or not...

of course it works...

the question is, can you do a passive blend with a smooth transition both ways, all the way through the range of the blend pot...

To accomplish this, you would require a pot that would do the following

1) when the blend is at centre detente, BOTH pots are at full range...turning the ganged pot more would only decrease one (not increase the other)
2) the taper on the ganged pot would need to be audio (for both, of course)

Then, you'd have a really good change of getting what you want out of a passive blend pot...I haven't been able to find a ganged pot with those specs...anyone?

All of them are this way. Are you sure you looked ?

 

[bongomania]

Why would you not want a blend pot to have a linear taper?...
Is this why some people have said their blend control does not blend except in the very extremes of the range - because the resistance (and thus the blend) has not changed much until nearly the full travel of the pot?

I have been wondering the exact same thing.

 

[Cristo]

Here's some interesting info, from Rane Profressional Audio reference:

balance control A control found most commonly on professional and consumer stereo preamplifiers, used to change the relative loudness (power) between the left and right channels. Attenuating the opposite channel makes one channel (apparently) louder. This is most often done (in analog designs) with a dual potentiometer with an "M-N taper." An M-N taper consists of a "shorted" output for the first 50% of travel and then a linear taper for the last 50% of travel, operating oppositely for each channel. Therefore, with the control in its center detent position, there is no attenuation of either channel. Rotating it away from the center position causes one channel to be attenuated, while having no effect on the other channel, and vice-versa. Contrast with pan and crossfade controls.

pan (panoramic) control A control found on mixers, used to "move," or pan the apparent position of a single sound channel between two outputs, usually "left," and "right," for stereo outputs. At one extreme of travel the sound source is heard from only one output; at the other extreme it is heard from the other output. In the middle, the sound is heard equally from each output, but is reduced in level by 3 dB relative to its original value. This guarantees that as the sound is panned from one side to the other, it maintains equal loudness (power) for all positions. Contrast with balance and crossfade controls.


This seems to describe the "volume drop in the middle" phenomenon that some people have experienced, and the nonlinear taper would seem to explain the "no effect until the end of travel" phenomenon. They are using a log taper pan pot (like what's at stewmac) instead of a a m-n taper pot.

Don't know yet what m-n stands for...

 

[bongomania]

AFAIK it doesn't "stand for" anything particular- the tapers of pots are referred to by an arbitrary letter code:
in USA
* A - Audio or Log taper
* B - Linear taper
* C - Reverse Log taper
* G - Graphic taper

In Europe
* A - Linear taper
* B - Audio or Log taper
* C - Reverse Log taper
* G - Graphic taper

And other letters, including D, M, N, etc. are used for other specific tapers, but there's no "word" correlation.

 

[PilbaraBass]

All of them are this way. Are you sure you looked ?

no they're not...you can get stacked linear taper pots...

those sold as "blend" pots should be audio taper, and usually they are...but, unfortunately, not all manufacturers use a proper blend pot...

my point is...the original poster is describing a blend pot response that is typical of LINEAR taper, not audio...

 

[Modulrob]

I almost didn't post here, there are other threads about it, so I'll summarize:

*) I like hot pickups. I've been playing 25 years, and have not really liked dual-pickup basses (never played a jazz bass, all had blend pots).

*) I've actually preferred a single pickup wired right to the output jack, over dual pickup basses with blend pots.

I *just finally* wired up my new bass pickups V/V/T (a Lane Poor Wide/HB combo, he suggested V/V/T in his pamphlet). I'm blown away at how detailed a tone you can dial in with this method. Even though you lose a "master volume", i.e. your volume changes as you fiddle with each pickup's volume, you've essentially removed a tone-sucking tone pot from the load (as opposed to the blend control, which essentially adds 2 tone pots).

I encourage anyone to try it out, I'm bummed I never tried it sooner.
- Rob

 

[PilbaraBass]

I almost didn't post here, there are other threads about it, so I'll summarize:

*) I like hot pickups. I've been playing 25 years, and have not really liked dual-pickup basses (never played a jazz bass, all had blend pots).

*) I've actually preferred a single pickup wired right to the output jack, over dual pickup basses with blend pots.

I *just finally* wired up my new bass pickups V/V/T (a Lane Poor Wide/HB combo, he suggested V/V/T in his pamphlet). I'm blown away at how detailed a tone you can dial in with this method. Even though you lose a "master volume", i.e. your volume changes as you fiddle with each pickup's volume, you've essentially removed a tone-sucking tone pot from the load (as opposed to the blend control, which essentially adds 2 tone pots).

I encourage anyone to try it out, I'm bummed I never tried it sooner.
- Rob

I'm confused by your comments...if you reread your post, you may be, too

I prefer V/V/T for control, because you can affect one pickup sound at a time...

overall volume changes do not bother me, because I control this through my fingers, firstly, and through my footpedal lastly...

When I'm playing live 95% of my dynamics come from my fingers...the only time I go for volume control is when I need MORE volume, and then I'll move my foot pedal from 80% to 100%...

 

[Modulrob]

I'm confused by your comments...if you reread your post, you may be, too

Ok, I'll translate to australian, The Queen's English

*) I never tried V/V/T, thought I wouldn't like it...I count on my right hand for all volume and dynamics, so I prefer one volume setting on my bass (even if it's a single pickup wired right to the output jack). Set and forget....

*) I just tried V/V/T and like how I have more control finding that one sweet volume/tone combo to leave it on. Much better than a blend pot, which I've noticed bleeds some tone on a passive setup.

 

[PilbaraBass]

I'm confused by your comments...if you reread your post, you may be, too

Ok, I'll translate to australian, The Queen's English

*) I never tried V/V/T, thought I wouldn't like it...I count on my right hand for all volume and dynamics, so I prefer one volume setting on my bass (even if it's a single pickup wired right to the output jack). Set and forget....

*) I just tried V/V/T and like how I have more control finding that one sweet volume/tone combo to leave it on. Much better than a blend pot, which I've noticed bleeds some tone on a passive setup.

ahhhh...English is such a beautiful language...(Even for a guy who spent the first 34 years of his life in Western Pennsylvania [me] )

Thank you,,,that makes much more sense...and I must say...I agree