Le Bubba Redux

[jubal81]

It took a few months - and a year of doing more FET overdrive layouts - but I've rebuilt the Bubba FET to make it much more betterer.

EDIT: Thought I should give this some more context. This is a rebuild of what I called the 'Bubba Fet' last year. It's 5 of my favorite FET-based gain pedals and a booster. There's a switch for the Klon (booster) and bypass for the Fet circuits. THe middle switch cycles through the 5 different effects.


Here's a link to the original build report.


Changelog:


Keefage!
Swapped out the Umble for a Lamprey (SVT workalike). The Umble never really moved me and I wasn't using it at all, so I had a year of 'tryouts,' doing layouts for different JFET drives and the SVT got the starting role. It really shines at both low and high-gain sounds.


Moar voltage!
The Blackbird, Lamprey, Plexi and Voxey Brown each got their own Road Rage with a 15V regulator, with the Black and Plexi rebiased at the higher voltage. JFETs really do sound better with more than 9V. I tried the RAH (mosfets) at 15V, but I actually preferred it at 9V.


Switcher switcheroo!
I did a new layout for the switching circuit for better and quieter operation. The inputs and outputs of each circuit are grounded on bypass, the switching and signal grounds are separated and I added big ground pads for using with shielded wire.


Wiring fanciness!
I got some 4-conductor shielded wire from Redco and used it for each effect and the input/output jacks. I also got busy with the hot glue gun and all the connections are really cemented together for stress relievin'. It wasn't very noisy before, but it's eerily dead silent now - and I LOVE that.


Capacitor insanity!
There are NO ceramic caps in this thing any more. I had to wait 6 weeks for the last few polystyrene caps from Hungary, so now all those small values are polystyrene. I did some A/B testing and the difference isn't 100% completely imperceptible. The biggest improvement comes when using them in treble-bypass positions, like on gain pots - and it's indeed small, but my philosophy more and more is that if I'm going through the trouble and expense, might as well go through the extra trouble and expense for the best.


Better Bypassin'
I replaced the relay switching (PedalSync chips) with 1776effect optotron bypass boards. The relay boards didn't make a popping noise, but the mute function really did sound like a hiccup in the signal and it was bugging me.


Moar Mojo!
The SHO was honestly kind of boring as a boost. After trying a few, I decided to go with a Silver Pony Klone and it's the balls. Really a superb EQ'd boost that sounds just perfect pushing these JFET ODs. Then, crank up the gain on the Pony and it gets monstrous. Again, poly and film caps in the Klone signal path with OPA2134 opamps and the BYOC-approved Russian diodes. I also made the Pony switch independently from the other circuits so I can use it on its own if I want to.


Faceplate frustration!
I tried TWO more rounds of etching new faceplates and never really liked the results. Instead, I glued photo paper on them and coated with epoxy. I think it looks pretty good, put I'm not overly thrilled with them.


The Results:
It took a lot of work, but definitely worth the effort. The sounds and functionality are greatly improved and it's super quiet even at high gains. Not to mention it's far more solidly put together inside. If anyone's thinking about a 2-in-1 drive pedal, I really have to recommend a Silver Pony Klone into a Blackbird (Black '65). It's just an amazing combo and insanely versatile.


Here are some cell phone pics. Gah, I really need a better camera.

[cooder]

That's a fantastic rework and upgrade to the max, awesome fab work Jason! You must be thrilled to bits now with this gain monster

So by having the 4 conductor wire to each pcb the fact that 9V power goes directly parrallel to in/out doesn't introduce any noise into signal this case obviously? I guess there could be a risk if the supply voltage isn't perfectly clean doing this?!?

Would be great to see/hear a demo, sounds like a terrific combo!

[jubal81]

So by having the 4 conductor wire to each pcb the fact that 9V power goes directly parrallel to in/out doesn't introduce any noise into signal this case obviously? I guess there could be a risk if the supply voltage isn't perfectly clean doing this?!?

Would be great to see/hear a demo, sounds like a terrific combo!

No troubles with parallel lines (they're twisted in there, too) on this build. I did run into trouble doing this with a really long, higher-capacitance cable. There wasn't any noise, but what I think was happening was the lines were acting as a capacitor and building up DC on the input of the next stage. (mucho popping).


I really need to do a demo, but I don't have the camera. I always use camera money for more guitar gear and electronic parts.

[wgc]

Awesome, thanks for sharing your findings, super helpful

[sonarchotic]

Beautiful work!

[davent]

Looks great!

For polystyrenes, high voltage mind you, there's this vendor in Toronto, 10pf-10nf, get things much quicker.

http://www.justradios.com/cart.html

[luks999]

wow thats just outstanding! that must be so much work
beautiful tweed enclosure

really cool switching system
did you make the case by yourself?