Throwing out the blend pot for individual volumes

evic777 · #1 06-30-2011, 05:19 PM

I have a Modulus Quantum 6 with 2 Bart p/u's and NS2TMB-18 3 Band 18 volt Preamp
The blend pot sucks (IMO)
I want to remove the blend and go with individual volume pots for each pick up

Can anyone give me a wiring diagram?
Would it be benificial or possible to keep master volume and install a stacked volume where the blend was?

Really enjoy the feed back and ideas on here.... don't let me down!
Thanks!!!

**line6man** · #2 06-30-2011, 05:29 PM

evic777 · #3 06-30-2011, 05:40 PM

Thanks Line6man
I was actually looking on the members list to send the request to you personnally.
You other posts that I've read have been a great help!

Do you have a suggestion on if I should leave the master volume in and go with stcked vol or just go with 2 individual volumes?
Thanks!

**line6man** · #4 06-30-2011, 05:44 PM

Quote:

Originally Posted by evic777

Thanks Line6man
I was actually looking on the members list to send the request to you personnally.
You other posts that I've read have been a great help!

Do you have a suggestion on if I should leave the master volume in and go with stcked vol or just go with 2 individual volumes?
Thanks!

A few people have done two volumes into a master, but personally, I think it's overkill. Perhaps you might consider a killswitch instead?

Do you have an active/passive switch? If the bass is active-only, I would put that master volume after the preamp, if you are going to have it.

evic777 · #5 06-30-2011, 06:01 PM

My bass is active only.... 18V
I was told that leaving the master would allow me to control overall volume with out loosing the setting on my two p/u but like you said I think its OverKill.
Simple seems best
The wiring diagram you shared is pre - preamp wiring. Correct?

**line6man** · #6 06-30-2011, 06:26 PM

Quote:

Originally Posted by evic777

My bass is active only.... 18V
I was told that leaving the master would allow me to control overall volume with out loosing the setting on my two p/u but like you said I think its OverKill.
Simple seems best
The wiring diagram you shared is pre - preamp wiring. Correct?

Yes, with two volumes, the volumes are always before the preamp.

walterw · #7 06-30-2011, 06:58 PM

why not just get a better blend pot?

a lot of bart systems have an "A/C" blend, which IIRC loses signal in the center, as at that point both pickups are turned down a bit.

an "M/N" blend pot will not have this loss, especially if you wire it without the ground connections (the "unloaded" or "ungrounded" blend trick).

**line6man** · #8 06-30-2011, 07:23 PM

Quote:

Originally Posted by walterw

why not just get a better blend pot?

a lot of bart systems have an "A/C" blend, which IIRC loses signal in the center, as at that point both pickups are turned down a bit.

an "M/N" blend pot will not have this loss, especially if you wire it without the ground connections (the "unloaded" or "ungrounded" blend trick).

Or try a buffered blend. He's already got a battery onboard.

evic777 · #9 06-30-2011, 07:43 PM

Walterw,,,
From what I have read, loosing the blend will open up the tone of the p/u's and increase the natural tone. Improving the clarity of tone is my only motivation.

I actually purchased a "M/N" blend pot (well, at least that is what I thought I purchased maybe it wasn't after all ???) and my tone suffered. Regardless of how I set the blend it was muddy especially at center detint. I still noticed a slight drop in volume at center as well.
I'm a "flat is my friend" kinda of guy.
It really bothers me that this change has forced me to have to add EQ!

I'm on the quest for the illusive perfect tone! LOL

evic777 · #10 06-30-2011, 07:44 PM

I do not know anything about a buffered blend. Can you explain?

walterw · #11 06-30-2011, 07:58 PM

Quote:

Originally Posted by evic777

Improving the clarity of tone is my only motivation.

then you want the "unloaded blend" trick!

re-use that M/N, but don't hook up any of the typical ground connections. just two pickup hots in, one jumper across the two pots, and one hot out.

this way, there's no extra path to ground to load down the signal, only series resistance "dimming" one pickup or the other when you turn it off the center detent.

unloaded like this, the blend has no tone loss at all, just like a switch.

evic777 · #12 06-30-2011, 08:23 PM

I'm game... can you point me to a wiring diagram?

SGD Lutherie · #13 06-30-2011, 09:18 PM

Quote:

Originally Posted by evic777

Walterw,,,
From what I have read, loosing the blend will open up the tone of the p/u's and increase the natural tone. Improving the clarity of tone is my only motivation.

Why would it? A blend is two pots, and so are two volumes. Use a 500K blend. Or try Walter's trick.

Quote:

I actually purchased a "M/N" blend pot (well, at least that is what I thought I purchased maybe it wasn't after all ???) and my tone suffered. Regardless of how I set the blend it was muddy especially at center detint. I still noticed a slight drop in volume at center as well.

Either its not an MN, the taper is bad, or you wired it up wrong. The side from the center that is near zero ohms goes to the hot. The other side that's close to the pot's rated value goes to ground. If you wire it up the other way it will suck big time. Each deck is reversed.

I also have to say that the best blend I have used is by Bourns. It's both pickups on full at the center.

But don't forget, with many two pickup systems, you will lose some oomph in the middle depending on how each pickup is voiced. Often the mids also notch out. This is normal for an unbuffered pickup mixing situation, and two volumes probably wont fix it.

Quote:

I'm a "flat is my friend" kinda of guy.
It really bothers me that this change has forced me to have to add EQ!

Sometimes you need EQ to get flat.

Use what sounds good and don't over analyze it.

Quote:

I'm on the quest for the illusive perfect tone! LOL

Aren't we all? That lead me to research and design my own pickups. That's taking it a bit far, no? lol

evic777 · #14 06-30-2011, 09:26 PM

SGD
It was one of your posts that lead me to purchase a Bourns. But I purchased the 250K because that is what Bartolini site suggested.
I'm taking it to a shop tomorrow to have it checked and see if it is wired wrong
Thanks again for your input

**line6man** · #15 06-30-2011, 09:43 PM

Quote:

Originally Posted by evic777

I do not know anything about a buffered blend. Can you explain?

Buffered blends supposedly allow a much smoother blending, with no insertion loss at the center detent. Instead of just running the pickups into two volume pots in inverse parallel, you buffer the pickups before combining them. That way the pickups don't load against each other, and pots don't vary a resistance parallel to them as you adjust the balance. The taper is supposed to be great, as well.

I've not tried one to comment on how well they work and how they sound, however. One thing to keep in mind is that if you run pickups into buffers before combining their outputs, the LCR of the two coils will not interact in the same way as with a passive VVT, VBT, 3VT, etc. setup.

SGD Lutherie · #16 06-30-2011, 09:49 PM

Quote:

Originally Posted by evic777

SGD
It was one of your posts that lead me to purchase a Bourns. But I purchased the 250K because that is what Bartolini site suggested.
I'm taking it to a shop tomorrow to have it checked and see if it is wired wrong
Thanks again for your input

If the blend is going to the input on the preamp, then the 250K is correct. If you are using it in a passive setup, or with a master volume before the preamp, than the 250K might sound darker because of the added resistance of the volume pot.

Either way it's a very small difference in tone.

This is the readings you should see on a typical MN blend. I took these from a 500K Bourns. You can see where the output and ground need to go from the readings. These readings were taken from the center lug with the pot's wiper parked at the center detent.

evic777 · #17 07-15-2011, 11:21 PM

To all of the players that commented especially SGD LUTHERIE....
I took your advice and had a tech rewire the blend pot "unloaded"
It is great! So glad I didn't go dual volume pot.
I must have wired incorrectly because it sounds great now...
Thanks again!

SGD Lutherie · #18 07-16-2011, 10:35 AM

Quote:

Originally Posted by evic777

To all of the players that commented especially SGD LUTHERIE....
I took your advice and had a tech rewire the blend pot "unloaded"
It is great! So glad I didn't go dual volume pot.
I must have wired incorrectly because it sounds great now...
Thanks again!

Glad it worked, but WalterW gets all the credit for the unloaded blend pot idea! I'm just an advocate of the idea.