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Different wiring for OBP1

gimmeagig

gimmeagig

Feb 25, 2004
2,891
1,198
Coeur D'Alene,Idaho
#1
Hi,
Before I have my bass tech rewire my bass I would like to get a second opinion probably from some of you electronic wizards here.
I'm still having trouble dialing in my Moon JB5 bass.Compared to my 74 Jazz w/stock pickups and a Sadowsky preamp it is not nearly as fat and punchy sounding.
I don't understand why.The Moon is a really high end well built bass.Swamp ash body, maple neck, great resonance unplugged,plays like a dream but plugged it it is kind of bland.Originally I had an OBP3 and Ultras in it then I switched to Basslines SJB5 pickups and an OBP1(for the lower treble frequency center).
It is better now but still not great.
On a different newsgroup somebody told me about a modification that he did for somebody that seemed to solve the same problem I have:
This is what he suggested:

"I wired his preamp the way Bartolini(REAL GENIUS!!!) shows in his
diagrams: It's about the flow of the circuit, ...

Follow this path---

1. The pickups are connected to the PAN POT, THEN (IMPORTANT)
2. Output from PAN POT should connect to the "INPUT of the PREAMP"(NOT
the volume pot)
3. The "OUTPUT of the PREAMP" should connect to the VOLUME POT (#1 LEG
- Left side viewed from top)
4. The Center Leg(#2) of the volume pot SHOULD CONNECT to the "HOT side
of the OUTPUT JACK."

Does that make sense?Has anyone here tried this?
 
#2
Interesting. That arrangement implies that in general, more signal goes into your preamp, since normal volume controls are passive, and therefore can't boost signal beyond it's input level. I'm curious to see if anyone here feels that the added signal going into the preamp makes a difference, since after the preamp, the signal still gets attenuated at the volume pot.
 
#5
FWIW:

I don't know squat about preamps in terms of construction, I've wired plenty of them, including in outboard form. I use the volume and blend leads as the ingoing outgoing leads to each jack when I do that.

I know terminologically (whoa!) I've thought of those leads as interchangeable but I'm not sure if that's actually the case or signal is predesigned to flow fixed directions.

At any rate, not major surgery (and I've tortured preamps to extremes and never phased one in terms of damage) so just do it and draw your own conclusion.

Personally, my guess is it's the pups (perhaps in combination with acoustic properties of the bass). A pup is not a pup as a pup is a not pup. They're different. I'm also guessing the Fender's 4 string. If the preamp thing doesn't cut it (do that first since it's a minor mod) and the Fender's a 5, I'd pull the pups from the Fender and stick them in the Moon and see what happened.

Also if the preamps are different or one is passive and one is active that could be a factor.

Ah, never had a Sadowsky pre. I definitely wouldn't rule that out as the source till I ruled that out as the source.
 
#6
By moving the volume pot from the pickup side to the preamp output side, you are lowering your load on the pickups and they will pass a few more highes. I doubt there is an earth shattering difference.

I think the SJB5s are hum cancelling. If you are comparing single coils to hum cancelling jazz pups, you may notice a difference as well.

Dave
 
#7
Hi all,

I recently bought the 1 aguilar obp, and I'm pissed xD. I've connected with aguilar diagrams and does not work does not sound. is a capsule emg dc bearing of 40 vol. is low 25k and 25k and treble. Now and I discovered something 'weird' when I connect the jack to the middle and low sounds somewhat distorted, but when I connect it does not sound completely .. HELP PLEASE

PS: I am Chilean and I am translating with google xD
 
#8
Juan fretlessbass said:
Hi all,

I recently bought the 1 aguilar obp, and I'm pissed xD. I've connected with aguilar diagrams and does not work does not sound. is a capsule emg dc bearing of 40 vol. is low 25k and 25k and treble. Now and I discovered something 'weird' when I connect the jack to the middle and low sounds somewhat distorted, but when I connect it does not sound completely .. HELP PLEASE

PS: I am Chilean and I am translating with google xD
Click to expand...

If you have a 25k volume pot, wired as Aguilar suggests, then you are loading the pickups down to the point of killing all output.
You either need the volume pot to run after the preamp, or to switch to a higher value pot, if it is going to be wired the same.
 
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