Repairing Preamp for Yamaha BBeast

[Opelka]

Hi,
I bought a preowned Yahama BBeast a couple of months ago. The preamp was replaced by a Bartolini active/passive one. The strange thing (at least for me) is that it has 6 knobs. After trying to find out, my conclusion is that the 6th knob controls the tone for the passive circuit, but it works when the bass is in active mode as well, and that is not part of the Bartolini preamp. Worst thing is that when you select either mic, it makes a buzzing noise .

The previous owner gave me the original preamp. When I decided to install it, I realized that the bass control was broken. Ok, so now I see why it was replaced...

So I have a couple of questions. If someone can help, thanks in advance.
* How do I connect the preamp back to the mics and battery? I couldn't find a circuit schema around.

* Where can I buy the original replacement for the bass tone control. The trebel has a sign in it: J 3B-50Komh A. If there is no original available, which would you recommend? (you will see in the photo that a friend of mine installed another one, but I would like to replace it with the original).

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Thanks in advance
PS: This is my first post after 5 years reading the forums. My apologies if i'm breaking any rule...

 

[diehard70]

IME the factory yamaha pre-amps have always been the weak link. This may have been instrumental (pun intended) for its replacement aside from the broken control.

I'm not sure what pre came in your BBeast from the factory. What year it was made?

 

[diehard70]

I'm not finding a schematic on either the NE-1 or NE-2 circuit at this time. Hopefully someone else can chime in...

 

[Opelka]

It was made in 1995. Do you need any number from the circuit to identify it?

Ok, I see. So, your advice would be to keep the Bartolini? (I would like to test it anyway)

 

[diehard70]

I'm finding everything except the wiring diagram for the pre-amp for this bass. IMO with active yamahas, in general, is the lack of dialing-in anything usable. I'm just not familiar w/ the NE-1 or NE-2 circuit and how much different it is to the standard pre-amps yamaha uses (tonally). I wouldn't want to steer you in the wrong direction.

I would stick w/ the Bart' pre, personally. But maybe that's just me. Sorry if I'm not much help. I have just never been a fan of the stock Yammy pre-amps. It's why my yamaha are passive.

 

[southernconfort]

hi

im prettyconfused now.
found on internet pic of ne1 preamp and is diferent from this in your post.
this preamp is same us mine in my trb jp 1.
so is this bbeast same like ne1 bass.
i have pdf diagram from trb jp1 but i think that your pickups have 1 wire more then mine pickups so if you wont i can send you in mail.
[email protected] is place where you can ask for original diagram(like me for my trb jp1).

 

[Opelka]

hi

im prettyconfused now.
found on internet pic of ne1 preamp and is diferent from this in your post.
this preamp is same us mine in my trb jp 1.
so is this bbeast same like ne1 bass.
i have pdf diagram from trb jp1 but i think that your pickups have 1 wire more then mine pickups so if you wont i can send you in mail.
[email protected] is place where you can ask for original diagram(like me for my trb jp1).

I'll send and email asking for the wiring diagram. In the meantime I sent you a PM with my email address. if you can send me your diagram.

Thanks

 

[southernconfort]

I'll send and email asking for the wiring diagram. In the meantime I sent you a PM with my email address. if you can send me your diagram.

Thanks

hi

I didn't get the pm ?

 

[Opelka]

PM sent again

 

[southernconfort]

hi

email sent

 

[BBeasty]

Opelka, I know this is way late but I just joined the forum and have the same bass with original electronics. Was your wiring dilemma ever resolved?

 

[BBeasty]

This is just an FYI for anyone else needing original wiring help. Each connection is labeled CN1= Neck Pup, CN2=Bridge Pup, CN4=Battery. The Black wire coming from the circuit board next to the pot closest to CN1&2 is grounded to the control cavity along with the black wire coming from each pickup.