Distortion pedals?

[katopan]

The RF Drive captures the vibe of a Zendrive but replaces all the hard to get parts with easy to get ones that give an equivalent sort of sound.

Cliff, any old schottky will do and the BAT49s you have will be fine (I used BAT46s in mine). But they do have to be schottkys - very different to silicon. And with this pedal it's the mix of softer schottky clipping on top of silicon clipping and the imbalance with two schottkys on one side that create the magic. Any similar looking circuits using silicon diodes don't sound even close.

[Cliff Schecht]

Cool yeah I know all about Schottkys, I've even designed them for a power semiconductor devices class and have used them on-chip in the few IC's that I have designed. I guess I was under the impression that the knees on a Schottky curve were sharper than a silicon diode because of the speed but there are other factors (on/off resistance of diode, on/off capacitance, minority vs. majority carrier device, etc..) that will definitely come into play here and determine how these devices will clip. Looking at examples of Schottky curves I definitely see the softer knee when compared to silicon though. Thanks for pointing that out!

There is no magic in these circuits or components IMO, if you were really keen to do so you could use even measure the characteristic of each type of diode, figure out a rough transfer function for them and predict how they will distort (either mathematically or through circuit simulation) before you put one in a circuit. I've run through these sort of exercises before (although typically in the RF domain) and it's actually quite entertaining and informative to see mathematically what harmonics you are to expect when something distorts.

But that math is a lot of work when it's just as easy to socket diodes and swap them out while listening .

Again thanks for the cool circuit, I'm going to build one up tonight and give it a shot.

[katopan]

Totally agree about the magic thing. My comment was more based on the magic of playing through a good circuit (amp or pedal).

It's easy to assume the schottky knee is going to be sharper than silicon especially relating it to the 0.2V odd threshold voltage. But they sound great.

I captured a heap of diode characteristic curves and posted over on
Wattkins for those who are interested - http://www.wattkins.com/node/16790

Let us know what you think of the RFD....

[Cliff Schecht]

I started building this on some nice double sided perfboard I found with a mix of surface mount and through hole parts but I'm not thinking this will be a permanent solution. I'd prefer to etch a PCB. Do you have the gerber files for the boards you made? The schematic you posted looks like Altium which I have but I prefer Eagle for quick single-sided layouts. I have both (and Orcad) if you are willing to share the schematic and board files instead of posting the gerbers. I have most of the parts needed to build a surface mount version of this (including some nice SMD 9mm Alpha pots) but I don't want to start a layout from scratch if I don't have to.

[sonicmojo]

Here's a new one about to come out. This is a self plug since I'm going to be making a batch of them. The boost is a straight up Dumble FET circuit. The overdrive is smoother rather than raspy but can get pretty gainy if you want. I researched various Tube Screamers, BB Xotic, the Keeley modded Bluesdriver, some of the other boutiques out there, etc. So then I made my own because I wanted a pedal that did both boost and a nice overdrive that could be turned down if wanted. It turned out so nice that I thought I'd make a small run of them and am almost there. A friend of mine uses it exclusively as the overdrive for the clean channel of his Lonestar at gigs. In fact, I'm building him another clean only amp (as a backup) to use with this pedal. This particular pedal excels on the clean channel of my Dumble clones, to the point of it really being hard to tell whether it is the Dumble OD channel or the pedal. Not kidding.

I'd be happy to have you try one out if you are up for shipping it back.

http://www.chilipedals.com

[Cliff Schecht]

Hey Bryan, that's a very nice offer! Let me throw together a few of the suggestions others made and see how they work out first. If I'm still frustrated after that, I'll let you know .

[stelligan]

Forumites odourboy & mdroberts make a damn fine OD pedal. FET dream. I dunno what it would sound like in front of your amp, but you can set it up to remain extremely tone neutral. I'd say it's low/medium gain? Kind of Zen Drive like without the mid hump. Same guys that do the CE chassis for amp builds. I can send you mine to test drive if you like.

[img:300:487]http://cepedals.com/images ... .png[/img]

[rdjones]

If you're looking for something that sort of captures the Express, take a look at this schematic:

http://www.lynx.bc.ca/~jc/meteorModded.gif

Doug Hammonds site seems to have disappeared, but the clips were pretty amazing.

Yes ! I like FETs.
I've got my own designs but nothing that elaborate.
Thanks for the link.

rd

[rsalinger]

The best Distortion that I have ever had the pleasure of playing, bar none, is the Brunetti Mercury Box - Liquid Distortion. Something of a ZenDrive II meets Plexi type sound.

I own an original. A friend of mine built a Clone, with this layout... They sound very similiar...

Gregor Hilden: http://www.youtube.com/watch?v=IwfTc8N4 ... ure=relmfu

[katopan]

Sorry Cliff, but the original PCB files and gerbers were developed for the Wattkins forum so I can't pass them out for distribution. Sure you understand.

After designing the PCB for the forum I also made up a surface mount version for myself with three RFD's on one board. Bypass and another footswitch to go from one stage to all three stages cascaded. Killer pedal in that format. If you do yours surface mount you'll get it pretty small because it's a fairly simple circuit.

Cheers,
Craig.

[Cliff Schecht]

Sorry Cliff, but the original PCB files and gerbers were developed for the Wattkins forum so I can't pass them out for distribution. Sure you understand.

After designing the PCB for the forum I also made up a surface mount version for myself with three RFD's on one board. Bypass and another footswitch to go from one stage to all three stages cascaded. Killer pedal in that format. If you do yours surface mount you'll get it pretty small because it's a fairly simple circuit.

Cheers,
Craig.

I hear ya and no worries. I managed to throw one together using whatever mix of SMD and through hole I could fine. First impressions are only at low volumes but I like how gainy it gets and it sounds good on both the neck and bridge. Sounds like it'll take a tube screamer in front of it well. I'll throw it at a bigger amp tomorrow and see if I like it with the full rig. If I like it I'll build a more permanent solution. I managed to fit this one with four knobs (using Alpha 9mm SMD pots) into a 1590B case!

[Cliff Schecht]

Pics of my new pedalboard (minus wah and foot controller for pitch shifter). Signal chain is currently as follows: homemade wah->pitch shifter->phaser->compressor->TS808 build->modified Blues Driver->RF Drive->chorus->Ibanez FL301 flanger->Alesis Microverb (rack mount verb).

I might end up swapping out the RF Drive or Blues Driver for a germanium fuzz if one beats out the other. I'd prefer to have one pedal set for distorted rhythm (BD2) and the other for slightly higher volume and gain for a nice lead boost but I'm yet to try out the RF Drive at practice. My first impressions were it delivered on the smoother distorted tones but after popping inside my Blues Driver and making a few more tweaks I'm digging the sound it makes much more than before. I played around with the tonestack voicing to knock out the heavy bass and emphasize the mids a bit more, I guess in a way I 'Wrecked my Blues Driver .