Baja Music Man guitar and bass onboard preamps

Post by **azrael** » 03 Mar 2010, 09:10

^Yeah, that's what I wa trying to link to a few pages back...
From page 2:

azrael wrote:Wait, I found this on eBay:
https://cgi.ebay.com/ws/eBayISAPI.dll?V ... 0390578219

Looks like the same layout to me....

PaulBass · Post by **PaulBass** » 03 Mar 2010, 17:42

Jarno wrote:Looks like somebody is using your work commercially, Baja. That's not very nice/ honest/ professional.

Paul, do you have a picture of the copper side of the board?

Jarno · Post by **Jarno** » 03 Mar 2010, 19:14

Apart from the fact that that big glob of tin looks like shit, those pads are connected so that shouldn't be the problem.
But maybe they made a mistake when they copied (and changed ever so slightly) the layout.

PaulBass · Post by **PaulBass** » 04 Mar 2010, 02:18

Jarno wrote:Apart from the fact that that big glob of tin looks like shit, those pads are connected so that shouldn't be the problem.
But maybe they made a mistake when they copied (and changed ever so slightly) the layout.

I'm gonna try and make one myself. never soldered together a preamp before, always bought them. I hope I can keep my hands steady when I solder that opamp socket. There is a demand for these preamps and I'm surprised nobody is making the boards. There is definitely a market for them. Ernie Ball just reissued the classic StingRay bass with this same vintage 2 band preamp.

junjie · Post by **junjie** » 04 Mar 2010, 17:03

sir bajaman may i know what is the correct value should i use for output coupling caps of the preamp, is it 1uf or 10uf?. thanks

bajaman · Post by **bajaman** » 04 Mar 2010, 20:34

10uf

Duckman · Post by **Duckman** » 04 Mar 2010, 21:55

The Usual Suspects

: IMG_3644br.JPG (53.96 KiB) Viewed 2493 times

try to resolder this points... who knows?

bajaman · Post by **bajaman** » 05 Mar 2010, 00:56

a picture of the component side would be more helpful if you want someone to help you fix it

bajaman

PaulBass · Post by **PaulBass** » 05 Mar 2010, 01:47

bajaman wrote:a picture of the component side would be more helpful if you want someone to help you fix it
bajaman

It looks exactly like this except there is on IC socket on mine

bajaman · Post by **bajaman** » 05 Mar 2010, 03:35

okay - but can you post a picture of YOUR board please

bajaman

junjie · Post by **junjie** » 05 Mar 2010, 16:10

sir bajaman im gonna try to use this preamp on a jazz bass copy but i wanted to costumize the controls into volume + volume + bass + treble. may i know if i can still use the two stock volume 250 pots. sir please help me to costumize the preamp to have an individual volume config. thanks

PaulBass · Post by **PaulBass** » 07 Mar 2010, 19:10

bajaman wrote:a picture of the component side would be more helpful if you want someone to help you fix it
bajaman

gonna desolder the board and test every part. I think one of the caps is bad. the chip is still good

collingtech · Post by **collingtech** » 18 Mar 2010, 15:22

thanks baja , sounds wonderfull :0)

edit: im using whit tl061 , deep bass and clear highs , i wondering here triyng to pos -mode that thing like putting some addicional parametric eq on end , i protobuild some ideas but the annoying distortion drive me crazy and i cant find the solution , im triyng to put this circuit behind aka alembic variable state filter
https://media.photobucket.com/image/ale ... ilter-.jpg

things i already try:
reducing the gain on 1 stage on parametric -fail
adjusting the input inpendance- fail
:0) any help will be great , sorry if i stolen topic space baja , tahnks in advance man

PaulBass · Post by **PaulBass** » 24 Mar 2010, 01:04

tried to desolder and the board was so bad all the pads and traces came off. I bought all parts so I gotta build one from scratch.

bajaman · Post by **bajaman** » 24 Mar 2010, 02:17

tried to desolder

use soderwick desoldering braid - no problems.

PaulBass · Post by **PaulBass** » 27 Mar 2010, 01:46

bajaman wrote:
tried to desolder
use soderwick desoldering braid - no problems.

I used a solder pump. the board was junk anyway. very amateurish. I threw it in the trash. I got another board and gonna solder new parts. and hope I dont do any solder run-ons. that opamp socket is gonna be a b****

Jarno · Post by **Jarno** » 27 Mar 2010, 07:17

Use only a slight amount to tin your soldering iron first, and then use the tin sparingly when soldering the socket and you'll be alright. First heat it up then apply a bit of tin. Also, look at what you're heating, if it the pad is bigger, aim your soldering iron at the PCB so most heat goes there, if the component is more robust (thicker leads) aim your iron more at the compontent leads.
When adding the tin, if you see it flowing on the component lead and PCB the soldering connection is ok.

PaulBass · Post by **PaulBass** » 31 Mar 2010, 04:46

I found the problem with the other preamp and the one I just built works fine. Bajaman's diagram is the only one that seems to be correct. Since I'm a noob I missed a ground connection. thanks for the diagram Bajaman!

bajaman · Post by **bajaman** » 31 Mar 2010, 08:52

I found the problem with the other preamp

That's good - and you learned something in the process

well done

Cheers
bajaman

collingtech · Post by **collingtech** » 02 Apr 2010, 18:53

baja ,you know how to modify this preamp to use whit active pickups?
thanks

Baja Music Man guitar and bass onboard preamps [documentation]