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HELP! OBP-3 in a Yamaha BB5NA

lgrankin

lgrankin

Jan 14, 2005
674
251
Ottawa, ON, Canada
www.facebook.com
#1
I'm installing an OBP-3 in my Yamaha BB-N5A... I'm re-using the stock active soapbar PUPs.

I completed the wiring as per Best Bass & Aguilar's instructions to accommodate the active PUPs, but it's not working... the only sound coming out of the bass is from some local radio stations! No sound whatsoever from the PUPs. :crying:

I purchased the OBP-3 pre-wired. All I had to do was connect the PUPs (white wire) to the blend pot, gound them to the back of the volume pot, tap (red wire) into the feed from the 9 volt and ground the bridge to the ouput jack.

I would luv any suggestions that some of the pros out there might have.

Thanx in advance,
LR
 
#2
I'm assuming that the pickup white wire was the pickup hot wire before - i.e. the wire going into the blend pot with your previous harness.

Was the jack pre wired? Or do you have a long jack that you wired yourself? Do you have pics? Also, Brian @ BBG is a stand up guy and will help you out where he can.
 
#5
I can't get the same kind of bite and grit that I could with stock preamp. I think it has to do with the combination of the Aguilar and Yamaha Pups... loads of midrange. It's impossible to get a decent slap tone now and the output seems relatively low compared to my other basses.

Had I known, I wouldn't have made the switch...

LR
 
#6
Hi,

I had a similar problem a few years ago with my Yamaha TRB6II when installing a Bart preamp for use with the Yamaha pickups.

What it boiled down to is a "buffer" had to be made up to match the preamp to the pickups (impedance matching?). This made a huge difference and sounded awesome without the hiss inherent in the previous Yamaha electronics. Slap sound and everything just off the planet. However after a while the bass ended up being too heavy to play standing up for long sets and I ended up selling it to a guy who looked like a gorilla compared to me.

I no longer have the diagram of the Yamaha TRB preamp circuit which has this buffer built in and the gentleman who did the mods and circled the part of the circuit on that piece of paper has moved onto other things.

If you can read circuit diagrams and get hold of the TRB6II or TRB5II or even BB5NA service manual from Yamaha or someone has a copy of the circuit layout, you should be able to pick the buffer part out and make one up. From memory, it is only a small part of the whole preamp circuit. The active preamp is reasonably identical in most active models of that series/vintage.

Sorry I'm not electronically proficient to elaborate further but I do remember the basic concept behind what my former luthier achieved for me back then.

Cheers,
Ozzie :eek:
 
#7
lgrankin said:
I can't get the same kind of bite and grit that I could with stock preamp. I think it has to do with the combination of the Aguilar and Yamaha Pups... loads of midrange. It's impossible to get a decent slap tone now and the output seems relatively low compared to my other basses.

Had I known, I wouldn't have made the switch...

LR
Click to expand...
well, the Aguilar flat has NO additional EQ. So it sounds like there's definitely something about the pickups alone or combo of pickups/prior preamp.
 
#8
davidmwilson said:
well, the Aguilar flat has NO additional EQ. So it sounds like there's definitely something about the pickups alone or combo of pickups/prior preamp.
Click to expand...

Turned out to be what my issue was too. If the gentleman wants to use the Yamaha stock alnico pickups, then based on my experiences here he needs a buffer circuit identical to the one used on the Yamaha active preamps to impedance match (or whatever it is) the Aguilar to the the pickups. The other alternative is to replace the pickups with some Barts or similar using the Aguilar as preamp. Here I would imagine the Barts to be a "standard" impedance and not needing any matching as opposed to the Yamaha alnicos.

I went down this avenue only after finding I didn't like the sound of Bart humbuckers and bart preamp in my Yamaha TRB6II as much as I like the bite of the Yamaha setup. But the hiss produced by the latter was annoying when recording which prompted me to delve in the first place.

Next step was to replace the op-amps in the Yamaha preamp with mil-spec equivalents and pair them with the original Yamaha pickups. This made a positive difference, however some noise was still evident.

Ended up replacing the preamp with the Bart 5.2 setup with the buffer mods and aaahhh - datz betta !!! . . . No noise with the slap and grit sounds intact.

So, given my observation here and my previous email, the same concept should work with the Aguilar . . .

Ozzie :eyebrow:
 
#9
Ozzie Boof said:
Turned out to be what my issue was too. If the gentleman wants to use the Yamaha stock alnico pickups, then based on my experiences here he needs a buffer circuit identical to the one used on the Yamaha active preamps to impedance match (or whatever it is) the Aguilar to the the pickups. The other alternative is to replace the pickups with some Barts or similar where I would imagine the Barts to be a "standard" impedance and not needing any matching as opposed to the Yamaha alnicos.
Click to expand...

One thing: when you were just using the first Bart preamp with active pickups were you using 250K/500K or 25K/50K impedance blend/volume pots?
 
#10
davidmwilson said:
One thing: when you were just using the first Bart preamp with active pickups were you using 250K/500K or 25K/50K impedance blend/volume pots?
Click to expand...

Hi David,

Can't remember, however, we did use a stock standard pre-wired Bartolini 5.2 preamp if I may say that. No internal mods made to this preamp at all in use with either the Yamaha alnicos or the Bart humbuckers.

The luthier just replicated the Yamaha preamp buffer circuits and added it in between the pickups and the preamp.

Wish I still had the bass. I'd be able to tell you the changes visually.

Cheers,
Ozzie
:hyper:
 
#14
I have a Yamaha BB605 that I really like - especially since I had Brian at bestbassgear.com install a pair of Bartolini jazz pups and a 5.4 preamp. The bass sounds MUCH nicer than the $350 that I paid. Add about $300 worth of Bartolini and bam..sweet bass.

I also had him install the same preamp and a couple of custom made Bartolini pups in my Carvin fretless 6 and again...bam...sweet bass.
 
#15
hands5 said:
so what type of preamp, pickups or both did you repalce them with ?
Click to expand...

Any yamaha electronics will always be the weak link in the chain.

I'm running EMG DC45's. I had an EXB system on it, but I eventually removed it because somebody broke it (long story)

Now I run volume/volume/tone and don't really need anything else. Someday I might put in a vari-mid controller, but the pickups so sweet by themselves it may stay as is for a long time.
 
#16
Above are some very good examples of how everyone's experiences and sonic preferences will always vary.

The main thing in this thread is that the original poster now has some options to go on considering he likes the slap and grit sounds of the Yamaha in the first place. And like me, depending on his sonic preferences, he may not get that with a wholesale change of electronics. Which is why I went for a compromise, mind you at a cost - and for me it worked. But it might not be cost effective or work for him.

A few on TBL that use Yamaha BB and TRB active basses have done the same thing however, they've had to fend for themselves as the chap I utilised found out he voids his service agreement with Yamaha when he does mods like this and secondly, he's no longer in that profession and has moved on.

I was in exactly the same position with my bass - I liked that slap and gritty sound but in my case the hiss from the preamp caused issues when recording. In the end I found I could closely retain my sonic preferences providing I interfaced the same pickups with the Bart preamp using a matching buffer. From what I hear, the Aguilar sounds like a very interesting alternative.

In fact, I'm now looking at buying a dismantled TRB5II for $200AUD from a close relative and doing the same mods but using the Aguilar OBP3 with the Yamaha pickups and the buffer preamp if I can find someone locally to do the work.

If this works, it will be an interesting addition alongside my MTD 635-24 and Mallia signature 6 fretless. One has Barts (MTD) and the fretless has Lane Poors (front - wide and rear - humbucker) with a Haz-Lab preamp (originally from a Fodera).

Cheers,
Ozzie :hyper:
 
#17
Thanks for the insight guys. All I know for certain is the OBP-3 and Yamaha PUPs don't get along well in the same signal chain. I'm hesitant to put much more $$ into this bass as it may become a back-up if I have my way. For the moment I'm going to re-install the Yamaha pre and hope that the old tones will still be there.

Thanks,
LR
 

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