John Hollis Omni Drive

[jeroen_verbeeck]

While building my latest stompbox (the OmniDrive) I encountered something irritant:
the pcb is really neat and compact, but how am I gonna build this on a prefboard ?
This would require me to use a lot of wires thus making it a ratsnest.
And that's something I'd like to avoid.

How would I go about arranging this on a prefboard ?

[Paul Perry (Frostwave)]

If I was making it, I'd use stripboard, rather than perf.

[RickL]

If you haven't already, check the 4ms site's CBCB (cardboard circuit board) method (you don't have to use cardboard, I use Formica). It's kind of a mix of printed circuit board and perf that lets you use PC board designs as patterns to build with perf techniques. In short, past a mirror copy of a P'n'P pattern of a piece of cardboard or Formica, drill the holes, insert the components from the opposite side and join them all together along the pattern lines using the component leads and extra wire if necessary. Check the site for more detail.

I've built dozens of effects, including the Omni Drive, successfully using the technique.

[soggybag]

I've made a few effects on perfboard from a PCB layout. I usually superimpose a gridon top of the PCB layout that represents the perfboard holes. The perfboard hole spacing is .1" (ten to an inch). Then I try and aligneach of the component pads at a hole. Then align the traces along the perf holes. Here you will need to square everything off and make right angles out of all fo the traces. 

[Mark Hammer]

The simplest way to make the Omni-Drive feasible on perfboard is to consider dropping a function or two and making it less ambitious.

For instance, the Mode switch simply places the clipping diodes in one of two ways, though I have to say that this does not produce a robust difference to my ears.  I can easily live without it.  Stick D3 and D4 in parallel with the Gain pot and omit C12.  Heck, if you want to save yourself some perfing hell, solder the clipping diodes directly to the Gain pot.

The Blend control is also something you can conceivably scrap without sacrificing too much, as is the Scoop toggle.  You can either keep the tone control network without R20, or if you like the sound of the scoop, the 10k (R19) and 1k (R20) yield .9k.  Actually, you can just sub any value between 10k and 1k for R19 to get different types of tone responses.  Likewise, the Boost function is not especially critical.  The switch selects between a gain of x10 and a gain of x3.  Chances are pretty darn likely you'll have far more interest in the x10 setting than the x3, so just wire up the first stage with R4 and be done with it.  C2 strikes me as a bit small in the higher gain setting so swap it for a .022 unit for a fuller sound.

I realize some find these functions indispensable, but I mention them simply because they are easy to identify and omit, without changing too much, and reduce the wiring demands by a noticeable amount.  Between the three functions we've just omitted, we've reduced the wire count coming off the board by eight, according to my count.

So what does this leave us with?  We still have a choice between filtered and nonfiltered, octave or nonoctave fuzz, variable gain/clipping, tone control and output level: two toggles, and three pots.  Not as "omni" as it used to be, but still capable of delivering a wide array of tones.

[jeroen_verbeeck]

Thanks for your advice.
I'll take it in consideration.

Is there maybe someone whos has some soundsamples of this pedal and it's functions ?
Because without hearing it I can't really decide wether or not I need those functions ...