Class of '77

[Leevibe]

Here is my latest labor of love. This was going to be my fall contest entry, but there were holdups in the process, so it didn't make it. I'll post the pics up front and add the TLDR section later for those who don't care to read a novel.























TLDR section:


For a long time I've wanted to build a pedal with a window into the guts but I couldn't think of a way to do it without ugly hardware around the top of the pedal. Once I got into messing with jeweler's resin, (aka envirotex) I realized I could try to encase an entire PCB in resin, put that inside the case, flow resin across the top, and that would give me one monolithic chunk of clear that would hold itself in place.

I had also been thinking of doing a PCB layout that would look something like the guts of a vintage tube amp. I thought it would be cool to make a board using gigantic pads that would be sized to accept turrets. So, I came up with this hybrid PCB that has some through-hole components and some turret mounted components. The goal was to lay the board out with the visual aesthetic as the primary concern, regardless of what that would mean for efficiency. Hence, this thing is a via-fest!! It's a terrible layout, but it looks so cool!

Even though I went for as simple a circuit as I could think of, it was still a crazy puzzle to figure out. I spent tons of time measuring, drawing, visualizing to get this to look right and still fit in a 1590bb. For the most part, I really lucked out with the way everything fit. One thing that I didn't account for was the size of the shoulders on the turrets. The OD of them was too big to sit side by side in the ring of turrets that makes up the opamp portion. So, I had my good friend Eric machine them down! Since then, I've figured out that I could have just cut them above the shoulder and let them sit on the little collar halfway up the turret. Oh well. It worked!

Eric is also the guy who did the machining for me. All of the cutting and engraving on the top was done by him using a CNC mill. I wasn't able to capture in pictures how good and jewel-like it looks.

There were many nail-biting moments in this build:

- seeing if the idea of soldering turrets to a PCB would even work

- firing up the circuit through my test rig for the first time. It didn't work!! I was terrified that I'd fried the metal can opamp. It takes so much heat to solder to turrets. I used a heat sink clamp, but still. It turned out (after MUCH studying the schematic and my layout) that there were two missing ground connections on the PCB, hence the jumpers on the bottom.

- firing it up AFTER I had scrubbed the PCB, worrying again that liquid may have done damage to the opamp

- making such a massive block of resin and wondering if I would get the amount right so it wouldn't overflow when I put the circuit into it. Also, wondering if I would get crazy amounts of air bubbles with no way to release them.

- firing it up after encasing it in resin!! It was a massive relief to hear it come to life. By that point I had put in a ton of work. By the way, I used a soap-making mold to cast the resin. I was lucky to find one exactly the right size. I had to chop down the depth a bit.

- flowing the final resin on the top. Black is SUPER unforgiving. I was also worried it might leak down inside the window and make a mess of all of my wire. I ended up using my hero, blu tack to hold the block in place while the top cured.

- drilling the resin out of the holes. Thankfully, no lifts!

- Wiring! I kept telling myself it was stupid to use ribbon! Every time I stripped a wire I was afraid I would break it. Every time I soldered, I was worried that the insulation would melt and go out of shape. There would be no turning back with this because all of the solder joints on the board were in resin.

- Being afraid that I would scratch the top while I was wiring.

- Finally firing it up after it was all together. So glad it works!!


There were also some firsts in this build:

- My first gooped board!!
- my first pedal with a window into its soul
- my first machined pedal
- my first turret/pcb hybrid board. I have to admit I thought it was my idea until I was later inside a vox amp.
- my first ribbon cable build
- my first use of carbon comps and axial caps in a build


I also want to say that I went into this understanding the many impracticalities of the build! I know I won't ever be able to replace the electros. I know there is more susceptibility to RF noise. I know the pcb layout is really bad from a practical standpoint. Hopefully it's clear that none of that was the point. This is just whimsical.

OK, so has anyone guessed the circuit? I will PIF one of these boards and a couple of those pretty blue Phillips caps to whoever can guess the circuit AND which parts in this pedal were purchased at radio shack.

DON'T POST YOUR PIF ANSWERS HERE! I'll make a thread in the PIF section and paste a link here

http://www.madbeanpedals.com/forum/index.php?topic=19001.0

nieradka guessed it! Knobs are Rat Shack. I've had these knobs for a couple years just waiting for the right build. For me they just really go well on this build. Who would have thought? Circuit is a '77 grey spec OD250. I needed something simple to make the concept work. This fits the bill and it's a great sounding circuit.

[GrindCustoms]

Ok Man, you win!!! No matter the contest.. you win!

Edit: Removed my guess... lol

[juansolo]

Holy shit 

/gobsmacked

[Haberdasher]

wow, yeah.  that would have done well in the contest.  sweet build bro.

[chuckbuick]

That is gorgeous.  I totally would have voted for that one.  Outstanding!

[billstein]

Ok Man, you win!!! No matter the contest.. you win!

Yep. Next contest already has a winner. That is unbelievable Lee. I may just stop building now.

[Stomptown]

I've been waiting for the unveiling of this monster for months now and I have to say it is more incredible than I imagined!  In about a year and a half, Lee has almost as many posts as I do over a four year period yet a serious lack of build reports.  I've seen a ton of his older builds and we've discussed a bunch of his in-progress builds and I'm just stoked that everyone else is getting a peak at the Evel Genius!  Well done Lee!!! 

[playpunk]

That could not be cooler


Sent from my iPhone using Tapatalk

[wstimson]

Yeah man, that is completely amazing. Well done, sir.

[micromegas]

Wow! Just wow!

[lars]

[brejna]

That is really REALLY cool pedal

[hoodoo]

  This is one of the coolest builds i think i've seen, totally original, very special, well done mate. I just hope none of those components ever die on you 

[davent]

That's made my day Lee! Too cool, outstanding concept and realization!
dave

[jubal81]

You've just won pedal building. OMFG.