Zvex Super hard on clone.

[valvefreak]

Well, it's been a while since someone posted here, but this is still one of the most useful sources if you want to build a SHO clone.
Thanks to LucifersTrip, because I couldn't find the schematic anywhere else and was to lazy to retrace it from all the perfboard layouts out there

So anyway, here are my experiences with cloning the SHO:

I built the whole thing on a breadboard with the parts I had laying around:
1M for R1 & 2
two 10K resistors in parallel for R3
5K pot for P1
BS170
1n4148 for D2 (I left out D1 in the prototype, because it would eat up too much space on the board)

I played around with it and soon added a master volume in addition to replacing P1 with two 1K resistors in parallel.
That all seemed to work nicely and I got out my soldering iron...
I had the idea to build the SHO into my guitar, so I would more or less get a "positive volume knob", but of course there were some difficulties: When I turned the Master vol all the way down, there would be no output at all, of course. So I put a random resistor that seemed to be about the right size (15K) in series with the volume pot -> I now had a minimum volume that was about the volume I would get without the booster.
I soldered the whole thing to a perfboard and tried to get it as small as possible, because I wanted the board to be carried by the pot in the guitar. I ended up with a 34mm long PCB, which wasn't optimal, since I used two components more than I would use if I had the right components (the parallel resistors for R3 & P1), but it did fit.

I've got a cheap singlecoil in the neck position on my guitar, which sounds pretty good, but is a little quiet. The SHO was a BIG improvement to enhance its sound, increase its volume, and increase the overall tonal options.
I'm very impressed with what this little thing can do and I can only recommend to build it, especially for beginners, because its easy to build and you get a GREAT sound. (If you use the right components: 1% Metal Film resistors and MKT caps )

Here are some pics:

Changed schematic, this is the one I used (except for the 10M resistors):


A view from the top (I've got an EMG81 in the bridge position)         //"Poti" is german for "pot"


A view from the side:           //"Für" means "for", yes.


I made a sound demo on YT, check it out: https://www.youtube.com/watch?v=GZ8ApeepzSE

Soon after that , I redid the whole thing in Eagle and ended up with a 27mm long board! I also added two 25-turn-trimpots to specify the gain and minimum volume.
I put the proper value for R1+2 on the PCB, since it probably sounds better/closer to the original. We will see...
Here are the Eagle files:
https://mega.nz/#!qsxRAKSQ!QpbVGv2SO8kuznW3F2yy7bemMGQDses1y9RK5FS2RRo
If you cant open them, please contact me. I used some custom components and I'm not sure if they are included in the files.
You can also order the PCB on OSHpark: https://oshpark.com/shared_projects/F8soVn0n


HOW TO USE THE PCB:
As mentioned before, I've added some trim pots. They're labeled "MIN_VOL" and "BOOST". Boost controls the Gain and MIN_VOL the minimum volume. If you jump "MastVOL" you'll essentially short out the MIN_VOL trimpot, making you able to use the the 100K pot as a master volume.
WIRE IT UP:
If you havent got an active system:
- Install the pot.
- Strip your wires back, tin them and prepare everything nicely.
- Solder your pickup/source to "+IN-", sleeve goes to "-", signal goes to "+".
- Do the same thing on the "OUT-" I didn't have enough space to fit a "+", but it is left to the -, looking from the front.
- wire your Positive battery wire to the "+" of V_IN
- wire your negative battery wire to the ring of your TRS jack
- wire the output signal to the tip, and the output ground "-" to the sleeve.
You're good to go, I hope you get the general idea

If you've got an active system:
Its a bit easier, because the battery and TRS jack are already there, just hook up a wire from the positive terminal of the the battery to V_IN +. Wire the I/O as above.

//Feel free to install 0.1 header pins and use it with the EMG solderless system

WARNING: Buy the PCB at your own risk! I haven't got them back yet and can not guarantee for anything!
As soon as I can test them out, I will let you know if the pcbs are OK.


Puhh, thats it for now.
If you've got any questions, feel free to contact me or post below.

cheers

[valvefreak]

UPDATE

The PCBs arrived! They're OK, everything fits. The copper pads for the resistors are a bit thin though, I'll fix that and share the new version.
Unfortunately the fabricator messed up the silk screen on these boards... But next week I'll get my order a second time, for free of course
OSH Park really has a great service, you can trust them!

Finished:


Documentation:


They're working really good, but they sound a little different than the prototype, probably because the trim pots behave different in comparison to normal resistors. Still a great sound and LOTS of options

Cheers