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Volume/Volume vs. Blend Question

Discussion in 'Pickups & Electronics [BG]' started by KJung, Nov 28, 2005.


  1. I did a search but could not find the answer to this. Virtually every bass I've owned has had a pickup blend control. Even on some very good basses (Fodera, MTD, etc.) the blend control seems to me to be more of an 'on off' sort of thing... i.e., there is a very small region where the pickups actually seem differentially blended (I play fingerstyle with the control just slightly blended favoring the bridge pickup), and then very quickly the control results in just one pickup or the other being totally on or off to my ear.

    I somewhat recently picked up a Celinder bass with volume/volume and for the first time, notice that I seem to have total control on blending the two pickups throughout the entire range of the pots.

    Sorry for the long winded set-up... here's my question... Is that a nature of the specific preamp and circuit in the Celinder (the Greengrove) or is that an inherent advantage of a volume/volume circuit over a blend control in general?

    Thanks,

    K
     
  2. mahrous

    mahrous

    Aug 13, 2005
    Egypt
    the exact same question was asked two weeks ago. check Page 2 and 3. u will find it there.
     
  3. I checked out that thread before I posted. Didn't seem to address my question, but I might have missed it. The jist I got out of that thread was they should pretty much work the same... that hasn't been my experience at all. I again might have missed the salient posts, though. Thanks.
     
  4. mahrous

    mahrous

    Aug 13, 2005
    Egypt
    blend pots achieve the same performance as vol/vol as many people have agreed on this forum and other forums.

    as for the specific bass you are asking about, you might want to ask the company themselves. You can experiment with different pots as well such as Linear or Log pots and so on till you find something that you like or makes you comfortable.
     
  5. Frank Martin

    Frank Martin Bitten by the luthiery bug...

    Oct 8, 2001
    Budapest, Hungary, EU
    I think the difference is right there.
    Log pots wired one way give very small increments, and towards the end, they increase exponentially. To put it simply, you have "nothing" (theoretically) at one end, almost nothing for a long time, then suddenly the whole signal.
    I'm still thinking of what pot configuration to use on my bass-in-progress: inverse log or linear...
     
  6. Interesting... that Volume/Volume (the first one I've had for many, many years) on the Celinder works like I had always hoped all those blend pots I have on MTD's, Fodera's, etc. would have worked... with a very smooth, gradual mix of different levels of each pickup versus the more 'on/off' type thing I experience after past 11am/1pm level on the blend control. Maybe it's the Linear or Log that you mention. Whatever it is, I've never experienced a blend control do what those two volume controls can do over their entire range. Thanks.
     
  7. +1... exactly what I experience with the blend controls I've experienced on all the basses I've owned. Thanks.
     
  8. I thought that was linear pots that did that, because we dont pick up sound increments linearly, its exponentially (10dB increase requires 10 times the amount of power)
     
  9. Didn't mean to bring this up and 'beat a dead horse', since it does seem like this has been talked about before. However, the difference in functionality was so large in my situation, and since I hadn't experienced a volume/volume circuit since my Ric in the 70's, I was just curious.
     
  10. BruceWane

    BruceWane

    Oct 31, 2002
    Houston, TX
    I've had mixed results with blend pots. A few that work as expected, but many that function more like a neck/both/bridge switch.

    I'm not an electronics expert, so I don't know exactly how this stuff works.........but from what I've heard from knowlegable people, the internal design of a blend pot causes the impedance of the pickups to interact differently from a V-V setup. This can be minimized if the resistence of the blend pot is precisely matched to the particular pickups used, but of course the problem there is that you can't get blend pots in a lot of various resistance values - all that's really available is 25K, 250K, and 500K.

    So the end result is that you will occasionally find a bass with a passive blend that works pretty well, because the impedance of the pickups in that bass happen to work well with an off-the-shelf blend pot.

    So, if you've got a bass with a blend that isn't working very well, you could try a pot of a different value. Also try some different vendors - I had one that I got from Stewart Macdonald that wasn't very good at all, so I tried one from Aguilar, and that one worked quite a bit better even though it was the same value. It's still not as good as I'd like, though. I've heard Allparts.com's blend pots are pretty good, so I'll try one of those next.

    Bear in mind that in all the above stuff, we're talking about a passive blend circuit. You can also have an active blend circuit. Active blends work much better than most passive blends, because each pickups impedance is isolated from interacting with the other pickup by using a buffer amp for each pickup before the signal hits the blend pot. It's more complicated, and I don't know of anyone making an off-the-shelf active blend circuit except for EMG (their BTC and BTS "systems" have an active blend). Unfortunately their circuit works only with their pickups. I have one bass with EMG soapbars and a BTC system, and the blend works flawlessly.

    Bartolini makes a dual channel buffer amp that I think could be used to make a buffered blend circuit. On their website they call it a AGDB (adjustable gain dual buffer). They also have some different models specifically made for blending piezo's with magnetic pickups.

    I've found all this info in a quest to get a good blend circuit in a Dingwall Afterburner1 that I've got. While the stock 4 way selector switch (neck/both parallel/both series/bridge) was pretty neat, I just didn't find the series sound to be very useful in a mix, so I decided to see if i could set it up something more flexible. I haven't gone so far as building an active blend circuit yet 'cause I haven't exhausted my passive options (still gotta try AllParts). And if that doesn't work I'll try a V-V setup before I try to squeeze more electronics into the control cavity; it's already pretty crowded in there, since I put an Aguilar OBP-3 in with a 5 knob set-up (Blend/Vol/Treb/Mid/Bass).
     
  11. mahrous

    mahrous

    Aug 13, 2005
    Egypt
    many luthiers have invested into electronics. each one claims something different for their own set.

    Aguilar are obviously a clear example. Benavente is another that claims different things about his own preamp. Ken Smith is another with what seems a pretty good preamp. Delano is another one i am dealing with that is telling me about his 'true-zero-impedance' blend pot.

    i am sure you are able to find a solution at most luthiers and electronics makers. if you have enough money to waste, start trying each one out till you find what you like!
     
  12. emjazz

    emjazz Supporting Member

    Feb 23, 2003
    Boston, MA
    I've been spoiled with Demeter preamps. They use an active blend and it blends flawlessly. It's the only one I've used that's been so precise. The only problem being that you can't switch the Demeter pre to passive. If you don't mind that than a Demeter preamp is a great choice.
     
  13. Marcus Willett

    Marcus Willett Supporting Member

    Feb 8, 2005
    Palm Bay, FL
    Endorsing Artist: Bag End - Dean Markley - Thunderfunk
    The Demeter onboard pre uses an active blend pot.

    Exactly. It is designed so that you can blend any two pickups of any sort (magnetic and piezo, for example) and have smooth, active blending. It's essentially like having a little mixer in your bass.

    I used the Demeter pre in a couple basses. It's a damn fine unit, but it's a wee bit bright for me, and it was hard to get rid of that brightness. It works pretty good with Barts tho.
     
  14. blend controls never satisfy me, i do prefer the vol/vol option so i can leave say the neck pickup at max and dial in the correct bite with the bridge pup at will..although on the last mexi jazz i played it was a bit dramatic...but the blend controls i dont feel like ive got as much control over the balance
     
  15. Frank Martin

    Frank Martin Bitten by the luthiery bug...

    Oct 8, 2001
    Budapest, Hungary, EU
    Linear: it's like connecting the two opposing ends of a square
    Exponential: as it's name says, exponential. Increases by more and more, but it only reaches half output at about 90%. From a volume pot view, if you turn a little, there is a drastic decrease.
    We've been putting together an experimental circuit for my new bass and there are 500k log pots. Wired the normal way, from the max, it decreased _very_ drastically, after about 1/4 there was no signal.
    Now we tried reverse log. This works far better. From the max, there is a gradually increasing attenuation. I can dial in the mix more easily and precisely.