First Build, The Supro

[diablochris6]

Recently, dropanchor812 asked me (in real life), "Deux yeux want to build a cool overdrive pedal instead of buying a neux JHS Superbolt?"  And I was like, "Deux I!  How deux we deux that, deuxde?"  And then he said, "We build the Supreaux Deux!"  With that, I will cease the "-euxs;"  I don't want to get booted off the forum with my first post for being annoying. 

Without further ado (aren't you glad I didn't write 'adeux!'), I present...THE SUPRO.


I believe the pcb came from OftenFX.  Most of the parts came from Mammoth.  The guts are a little sloppy. Being my first build, I am not quite economical with wires, but the slop does provide a barrier so the populated board doesn't touch anything to short it out.  For the logo, I designed it on paper, made a stencil out of it, and after I sprayed it, I fine tuned it by scraping the enamel with a toothpick and using a brush to reapply if needed.  I sprayed a clear enamel over this for protection, but I still managed to create a nasty scrape with a wayward pair of pliers.  ALWAYS COVER YOUR DECALS DURING ASSEMBLY TO PREVENT DAMAGE!!!

I was worried for a day because I wasn't getting any sound out of it, but after twiddling around and biasing the transistors, it works marvelously.  This fits perfectly with the Tele that I just built.  I might fiddle with the trim pots a little more.  For those of you with this pedal, do have any suggestions for the trimmers?

[hoodoo]

Great first build mate, and a funny f@#ker, look forward to your next post, All the best, Matt.

[Mike B.]

Yeux Geaux Deuxde! Haha funny indeed. Welcome, and nice first build too!

The trimmers should be adjusted until you get 12v on the "Drain" lead of each JFET. If you don't have a multimeter yet, you can bias by ear but I highly recommend purchasing one if you plan to continue building. Doesn't have to be anything fancy - a cheap one from your local Rat Shack will do nicely.

[midwayfair]

Excellent first build.

+1 euxn getting the multimeter.

[jprizz]

Great fisrt build! And don't worry about the gash from the pliers it only adds character! Besides there are lots of folks out there paying big money for someone to do just that to guitars to make it look like they have played the snot out of it, instead of just playing the snot out of it...

[wstimson]

The trimmers should be adjusted until you get 12v on the "Drain" lead of each JFET. If you don't have a multimeter yet, you can bias by ear but I highly recommend purchasing one if you plan to continue building. Doesn't have to be anything fancy - a cheap one from your local Rat Shack will do nicely.

Yep.  And that board has convenient test points on it.  Those square pads labeled 1, 2, and 3 next to the transistors are test points.  So get out (or go get) a multimeter, turn it to the DC voltage setting, put the black probe to ground and the red one to each of those test points and adjust the corresponding trimmer until you get to the appropriate reading on the multimeter (about 12v).

[diablochris6]

Thanks for the advice. I, in fact, do own a multimeter. I used it on the test pads on the pcb and measured the bias at 12v, I was just curious if anybody has tried tweaking those numbers a bit.

[fendman]

Nice build ya nah!!

Mike

[midwayfair]

I was just curious if anybody has tried tweaking those numbers a bit.

You can get more or less distortion and gain out of the circuit by lowering the bias points to 9v or even lower (like 7v, especially on the last FET).

Whether or not you want to is a separate matter. This is a kind of complicated article about the basic circuit in the Supreaux Deux, the "Fetzer Valve":

http://runoffgroove.com/fetzervalve.html

Part of this explanation is the implication that biasing anywhere except 2/3 supply will result in an incorrect balance of harmonics of various orders.

Of course, your ears are the final arbiter.

[diablochris6]

I biased the transistors at 12v, and the pedal seems to work fine.  I might drop the voltage just a smidge for a little more gain.  One thing I noticed was that the tone knob doesn't change the sound at all when I turn it.  I might have a bad connection between the pot and pcb, or the pot itself might be bad.  Is it possible for the circuit to still produce sound if the tone knob is not connected right?

[dropanchor812]

It seems kind of silly for me to say "great job!" here on the board since you brought it over here tonight and rocked it.  However, since my ears have bore witness to the sweet subtle gain of this pedal I will congratulate you in front of the only other people we "know" that have any idea what this gadget is.  So... good job.

P.S. Mine is gonna be so much better. 

[eldanko]

ALWAYS COVER YOUR DECALS DURING ASSEMBLY TO PREVENT DAMAGE!!!

This is a FANTASTIC first build sir! The Supreaux circuit has been on my list of to-builds for a long time now. Glad you dig yours!

And per the scratch - I've done that more times than I can count. At this point, I consider it a blessing... sort of getting the first battle scar out of the way. I have to repeatedly remind myself that these things are made to be stepped on!

[diablochris6]

Eldanko, I highly recommend you get to this build!  It is very attack sensitive.  I tend to strum and pluck with my fingers, but when I use a pick with this pedal, it really distorts.  The tone knob is real subtle; you might want to look into using a different pot value or something.  It does the trick for me, but one of my friends was asking if the tone even worked.