BIXONIC: Expandora

OK - so this is what happens when you agree to make a pedal, before knowing what someone might ask for.   I'm not sure that this is 100% my kind of thing, but here it is.

Yes it's a huge layout, but it is going in a 1590XX enclosure, so why not.  I started this layout using the Dirtbox Layouts Expandora vero layout (and basically made it wider), as the first version that I did had a few too many rows, for the space available in the enclosure - and I will probably only be making one of these.  So credit where credit is due...  

I may still add the guitar / bass switch - see how it sounds.  There is room on the board for it.  Not hard to work out if you want to add it.  

If you are unfamiliar with the signal flow on the Expandora - it's kind of a Rat with an extra gain stage up front, and an unusual compressor like gain control that's always on, which is combined with a couple of switches to help set the overall gain of that stage.

The fun doesn't start until "forbidden mode" is engaged - which opens the gain right up.  Talking big ugly square waves.  The Expandora moves from a fairly innocuous drive or mild distortion, to a full blown fuzz monster.     

BIXONIC EXPANDORA

This is it on the bench for some testing - just a bit of rough / temporary wiring to confirm all works as expected, before I wire it up properly.    I think the tin can LM308 opamps look cool, and they were all I had.

It's been a while since I worked on small vero, or should I say normal size.   It took some adjustment, and I did have a tiny little copper trace left on a cut that took a decent amount of time to track down.  It took a magnifying glass and a multimeter to track it down - the damn thing was about the size of a bee's dick (which is a unit of measurement in Australia). 

Now this is mainly for my own purposes, as I doubt anyone else will want to build a Rat this way & I only plan on making one.  

Just a standard Rat, built on 0.15" vero and I've prioritised looks of build practicality (or at least what I think looks good anyway).  I have built this, and can confirm that it works   

PROCO RAT - 0.15" VERO LAYOUT

The layout probably makes more sense with a photo as a reference

GREER AMPS: Tomahawk Deluxe Drive

This is a simple one from Greer Amps - the Tomahawk Deluxe Drive.  It has some distinct similarities to a Rat or Distortion +, in that there's opamp clipping, driving hard clipping diodes, and a tone control. 

Schematic from PedalPCB.   I added a buffer on vref, as half the opamp wasn't being used, so why not.

GREER AMPS TOMAHAWK DELUXE DRIVE - VERO LAYOUT

GREER AMPS TOMAHAWK DELUXE DRIVE - VIDEO DEMO

BARBER ELECTRONICS: Edge Hog

Check out the video, as it includes a tear down, schematic and a great explanation of the Barber Edge Hog circuit by Gray Bench Electronics.  He has a few other video that are worth a look too - hopefully more traces to come...   

BARBER ELECTRONICS EDGE HOG - VERO LAYOUT

note that I did change the 4.7u to a 100u for power filtering, and I skipped the power protection diode on the layout.  Still room for it if you want to drop one across V+ / V-    I also used regular caps instead of tantalum, for no specific reason other than I don't have any in stock.   

INVENTIONS: 1981 DRV

The Inventions 1981 DRV is a modded Rat, and it's a pretty nice one.  If you wanted a more 'hi-fi' Rat, this would be it.  

It runs at 18v, which undoubtedly helps with the more open sound/dynamics compared to an original Proco Rat.  There's also a slight boost before the main op-amp, where the drive takes place.  An op-amp also replaces the simple JFET buffer found on the output of the original Rat.

It's running buffered bypass and should be easy enough to convert to true bypass if that's your preference.

Schematic available at Pedal PCB

INVENTIONS 1981 DRV - VERO LAYOUT

1981 VIDEO DEMO

PROCO: Rat, with mods

The humble Proco Rat - a staple of distortion throughout the 80s, and then later rediscovered by people that couldn't afford expensive pedals or just liked the sound.  By the way, I refuse to acknowledge the Rat as a fuzz pedal.  Others may, but not me...

Excellent analysis on Electrosmash if you have somehow missed it - link here 

The layout could be smaller, but I like a bit of room on the board, and it's still only 21 wide.

PROCO RAT WITH MODS - VERO LAYOUT

This modded Rat has switching diodes and an adjustable highpass mod using trimmers.  The straight Ruetz-style switch can be a bit much for some people, so the option to dial it in via trimmers and leave it seems like a reasonable idea.

The switching allows for a few diode combinations or just leave off the LEDs for an open setting.

Same again, but without the trimmers.

It's a Rat...   and of course you can build any version of the Proco Rat using this point to point layout.   Pop the Earthquaker Devices Tentacle in front of it and a boost after it,  and now you have a Sunn Life pedal.  

PROCO RAT - POINT TO POINT LAYOUT

 

PLEASE NOTE:  Different coloured lines are not joined.  I hope that obvious, but thought I should mention it anyway.