Omnidrive review

Taylor · May 07, 2009, 02:09:02 AM

I built John Hollis's Omnidrive. The idea of this circuit is that most drive effects can be broken down into a few building blocks, so by giving you all the blocks in one circuit, you can get all kinds of different distorted sounds. I'm doing this thread because there doesn't seem to be much talk about this (other than in the Archives, where all the posts are out of order and hard to read) and I thought somebody might have some interest.

Quick background, I'm not a big drive fan. I'm usually more into weird effects (mainly ring modulators) and the differences between the endless drive pedals are pretty uninteresting to me. I built this to cover a lot of bases without having to build a bunch of different things.

Most discussion of this has been "how closely can this emulate a Tube Screamer/Big Muff/Metal Zone?", but I could care less about that. If you need to A/B pedals to hear the difference, why does that difference matter? Further, who cares about sounding specifically like a TS/whatever? (Well, a lot of people, but anyway...) This is a very very cool design.

I'm able to get very subtle grit and sharp attack on one setting, Big Muff bass squalls, over-the-top sounds kind of like the 4MS Noise Swash, all your typical drive sounds, etc. Now, I'm positive that fuzz fanatics will find that this doesn't sound enough like a Fuzz Face to them, so you probably shouldn't waste your time if you already have a ton of drive pedals built. But the Omnidrive has a lot of different and great drive sounds available, and not just generic stuff.

The one bummer is the "octave" setting. I have built a couple of Ring Stingers, and the octave sound in that is way more pronounced, but I honestly don't use it too much. The octave on the Omnidrive is barely there. It gets some nice ring moddish intermodulation sounds when playing double stops, but I can't really coax an octave out of it.

Anyway, I recognize I'm not the model dist user, but I think this is going to cover all of my drive needs quite nicely.

Quick tip for those using the schem instead of R.G.'s layout: Hollis uses what looks (to me anyway) like a ground symbol, to mean Vb/Vref. Tie all those little squiggly triangles together. The grounds are the horizontal lines at the bottom. Here's R.G.'s schem which makes it a little clearer:

http://www.geofex.com/PCB_layouts/Layouts/omnidrv.pdf

I couldn't get the thing working for a day because I had tied all those to ground.

So, in summary, this thing's cool, give it a go if it sounds interesting to you.

oldrocker · May 07, 2009, 10:11:48 AM

Well I agree with everything you said except the part about the octave part. Personally I don't think it's subtle at all. In fact the octave part is on of the things I most like about it. You might want to check your build because when I first debugged it I had the same problem. After double checking I realized I made a mistake. Although it's most likely a matter of opinion.
There was a thread where I mentioned the problem and then found out what it was. I couldn't find the thread so I can't tell you what I had found. But like I said it's as good as the Scrambler and better than the Green Ringer. My favorite octaver is the Neoctave from R.O.G.
I added 6 LED's for the different settings and that combined with the 5 toggles and 4 pots really crammed up the box but it was worth it.

Paul Marossy · May 07, 2009, 11:27:33 AM

I've always wanted to build that one, but never did. Maybe I will one day just for kicks...

timotet · May 07, 2009, 01:00:24 PM

Ive got it on the breadboard right now I think this thing rocks, and the octave is definitely there.
I like this build alot.

Taylor · May 07, 2009, 03:14:53 PM

Quote from: oldrocker on May 07, 2009, 10:11:48 AM
Well I agree with everything you said except the part about the octave part. Personally I don't think it's subtle at all. In fact the octave part is on of the things I most like about it. You might want to check your build because when I first debugged it I had the same problem. After double checking I realized I made a mistake. Although it's most likely a matter of opinion.
There was a thread where I mentioned the problem and then found out what it was. I couldn't find the thread so I can't tell you what I had found. But like I said it's as good as the Scrambler and better than the Green Ringer. My favorite octaver is the Neoctave from R.O.G.
I added 6 LED's for the different settings and that combined with the 5 toggles and 4 pots really crammed up the box but it was worth it.

Hmm, maybe something's wrong with my octave circuit. Could also be a matter of finding the right diodes. I'll search around for your earlier post.

That is nuts that you fit all that into that little enclosure. The circuit's not huge, but there is so much offboard wiring. Nice job, would love to see a gut shot.

iloophao · May 08, 2009, 03:54:23 PM

mine also has some problem!!! i don't why!

look this

soggybag · May 08, 2009, 04:59:15 PM

I built one these a few years ago and never boxed it up. You guys are inspiring me to get it and give it a second listen.

I don't remember seeing a lot of mods for this. Maybe it could be improved upon with a careful selection of parts or with a few tweeks.

skiraly017 · May 09, 2009, 12:22:12 PM

Are there any sound samples for this?

oldrocker · May 10, 2009, 10:28:18 AM

I've never made sound clips for this since it has so many different to be had. The question was, "which sounds from the Omnidrive should I record?" So you would have to make at least ten clips to cover everything this pedal can do. Maybe I will soon.

mnordbye · May 10, 2009, 06:28:59 PM

I just finished up an Omnidrive as well, and have the same octave "problem" as you. It's not really audible at all. Can it have something to do with the diodes?

Mackin · May 10, 2009, 06:35:02 PM

Quote from: skiraly017 on May 09, 2009, 12:22:12 PM
Are there any sound samples for this?

Oh yeah, I'd love to hear it

Taylor · May 10, 2009, 06:40:33 PM

Quote from: mnordbye on May 10, 2009, 06:28:59 PM
I just finished up an Omnidrive as well, and have the same octave "problem" as you. It's not really audible at all. Can it have something to do with the diodes?

Here's another thread about this:

http://www.diystompboxes.com/smfforum/index.php?topic=42755.0

Haven't tried any of Mark's mods yet, though. Since my Ring Stinger has a very pronounced dirty octave sound available, I don't care too much about getting this to work in the Omnidrive, but I am interested to hear if anyone else tries it.

maxj · January 05, 2011, 03:20:54 AM

Quote from: Paul Marossy on May 07, 2009, 11:27:33 AM
I've always wanted to build that one, but never did. Maybe I will one day just for kicks...

Oh trust me for a DIY pedal maker this is a must. I've gotta say this is the most reliable pedal I've ever come across. It's been three years since I've built it and still it works fine. Instead of TL072s I used 4558s because my closest electronics shop was out of them. The only issue was I couldn't notice any difference when switching between mode, and the boost didn't work. This pedal is pretty much all the common effects we get to hear everyday (Other than delay, reverb, chorus). And you can have lots of variety on different presets.

This link shows a nice demo of it. Very neatly done.

http://www.youtube.com/watch?v=aUPJwyQ9LY4&feature=related

I'm looking to mod this thing further, any suggestions?

BTW Octave worked fine for me

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Omnidrive review