freestompboxes.org

caspercody wrote:Anyway to get more gain out of this?

Like any tube amp that needs more gain and tightening up for metal, boost it with a treble booster...

Could do something like build a tube screamer with pot values hard set - zero gain, max volume, middle tone. Then insert that circuit between the FET buffer stage and the first opamp

I put a 27K ohm resistor in the first stage, and a 10k ohm in the second stage. I changed the 2.2uf to 220nf in the first stage, and the 1uf to 330nf in the second stage (closet values I had to the calculated 213nf and 270nf)

Now this thing has gain. I am hoping the calculated values i choose for the caps still keep the characteristics Baja had in his design?

Thanks
Rob

It took me a looong time to complete this build doc..

ubs_build_doc.pdf

T.

Thanks for the doc.!
I already built the VH-4 emulator and love how it sounds.
How about using the PCB board from the VH-4 project and set in the values from the UBS?
Shouldn't be too hard to get the circuit replaced but there's the 24V charge pump and the additional depth control. Do those differences change the response a lot?
There's probably more headroom so should the charge pump be omitted?



Thanks a lot!

Were would you go about putting a tone stack at were would you connect it at.

Any help were to put the tonestack thanks.

Between last transistor and VOL potentiometer. Check my build document, couple posts above. Or check other schematics from bajaman that include tone stack - BAJA EVH for example.

T.

Thanks for the info. Feel dumd now not to think to look at other schematics lol.

Update:
Increased 1st stage gain and changed a coupling capacitor, resistor etc. also added a Bogner style tone stack with three preset pots accessible from three small holes in the bottom panel - set and forget ! Tried it at a jam session today - really liking it with treble set to zero, mid set to 10%, and bass set to about 20%
Here is the updated schematic:
cheers
bajaman

I made this board for the BAJA UBS and I'm more than happy with the ton I can get out of it!
I've designed it with the send and return pads so its possible to attach and try out different EQs, so far I've tried it with the Amp tone stack + Recovery gain and I really like it, pretty loyal to the amp sound tone wise, and I've also tried out a Hybrid EQ that mixes a Baxandall for Low and Highs with an Active mids control, giving me a really interesting result as well, pretty flexible to shape this amazing drive!
I'll keep on researching and I'll be making some videos testing with different tone stacks
Also I just found the new Baja update for extra gain, and as far as i can see i could replace those values on my board to try it out, maybe on the final version it could be a DPDT that switch in between the original version and the new one with extra gain... But I should try that out first
Hit me up if you are interested in some boards

Are all layouts there verified? I would like to make by one of them