Bass preamp

[erick4x4]

So I have a buddy with an old stingray and the preamp has gone. It distorts real bad. After calling ernie ball, it appears to be an old preamp that often fried the opamp, and its covered in enamel so I'm toast. So they can send me a "trade out" for $75, but I though, maybe I could make my own. Theirs has lots of cheap parts (cheap IC, tantalum caps, etc).

Any good designs for a 2 or 3 band eq bass preamp, that would be small and easy?

Thanks!

[nordine]

nothing touches the FLIPSTER:

http://runoffgroove.com/flipster.html

ain't your 1 or 2 transistor design, but ain't rocket science either.. and for what it is, is worth the extra effort

that amp emulation (used as a preamp), no matter how weak or muddy your bass signal is, gives you rattling and ground shaking bass tones... while retaining a very refined edge on the higher register

don't know about it's OD properties -because my FETs are VERY low gain-, but it sure rocks... i like it clean, btw

[Bernardduur]

I used J201's and it is both clean as OD'ed very nice!

But in a bass, check out the NTMB Bartollini clone on this forum; a very good bass preamp

[MartyMart]

Another possibility :
http://aronnelson.com/gallery/Martys-layouts-and-photos/BassBoy59?full=1

59 Bassman emu

Marty.

[trevize]

albert kreuzer has some good preamps an onboard preamps fpr bass in his webpage.

he has also very good layout and pcb designs.

http://www.albertkreuzer.com/start.htm

[Bernardduur]

albert kreuzer has some good preamps an onboard preamps fpr bass in his webpage.

he has also very good layout and pcb designs.

http://www.albertkreuzer.com/start.htm

Yes, he has a great preamp in his section!

[Branimir]

Bass player from my band built the JFet preamp for bass guitar (http://www.albertkreuzer.com/preamp.htm), and he's using it with a Crown CE1000 into 2x15" (RCF speakers, can't remeber which ones), and it's great! Lots of good tones from the preamp, has a nice compression (sort of) circuit...

Two thumbs up!

ps: browse this site for schematics http://www.akustische-kunst.org/audio/index.html i think you can find a schem for a D.I. circuit (unbalanced to balanced), it could be incorporated into the preamp of the mr. Kreuzer's preamp to get balanced input for your preamp, and therefore avoid using D.I. boxes when playing live... At least you'll get your tonestack tailored sound out of the D.I. out on the preamp

[Mcgiver69]

This is a 3 band preamp that can be used onboard.

http://img.photobucket.com/albums/v467/Mcgiver69/3bandEQ.gif

And this one is a 2 band preamp

http://img.photobucket.com/albums/v467/Mcgiver69/basspreamp.gif

I think this will help.

[vanessa]

You could always go with the original...

http://myweb.ecomplanet.com/TOWN8019/mycustompage0019.htm

[erick4x4]

Anyone know of any of the above where someone would sell me the PCB? I have never messed with making my own, I either perf it or buy the PCB, but in this case I need to be small so PCB seems like the only option.

[George Giblet]

The 2-band MM preamp is part of the MM sound.

It's probably easiest to replace the opamp on the existing board.

Use the non-potted preamp pic on the link that was posted earlier to navigate through the components.

Pick or grind away the epoxy.  There's a few references in the archives about using chemicals to get that stuff off - however the MM epoxy might be different to those.

When get you down to the IC,  grind or cut the legs off.  Do whatever it takes to make your life easier.  You don't need to save the IC (it's an LM4250).   

Getting rid of the epoxy on the bottom of the board without damaging the tracks will take some care.

One option is to grid out the IC leaving the legs hanging on the component side of the board then just tack solder the new IC onto those - that way you don't have the clear away so much epoxy.

[vanessa]

UPDATE:

I'm sorry I did not see your post about the epoxy. On a vintage piece like that I would have him spend the $75 or go hunting for the original parts. Those basses are worth a lot of money on the vintage market. I just saw an original vintage preamp for I believe a Stingray up on eBay.

[col]

Eric,
I recently built the flipster on stripboard. If you would like a digital photo of the hand drawn schematic please pm me and I can send you one. It works well with my guitar after my pedal chain into my 10" practice amp and makes it sound like my stack. It really does shake the house! Strangely it also works very well with bass. I used 2N5457s and found them quite hard to bias, I ended up doing it by ear. The bass and treble controls are very wide ranging.

Col