First Impressions of the Expandora Squared Compact Distortion Fuzz Overdrive Pedal - LM308AN Edition
So back on September 10th I announced the return of the Expandora pedal where the fairly recently minted Expandora Pedal company had taken on the Bixonix Trademark and started making Expandora pedals anew in various different editions and enclosure sizes. In fact there had been a soft launch at the start of the year which I missed, and it seems that 3 varieties have been commonly available on Expandora’s Reverb.com Store for quite some time :
- $225 - Squared Regular Compact Edition : with U1 TI RC4558P + U2 TI OP07DP + U3 TI OP07DP
- $250 - Squared LM308 Compact Edition : with U1 TI RC4558P + U2 National Semiconductor LM308AN + U3 National Semiconductor LM308AN
- $270 - Vintage LM308 Round Edition : with U1 TI RC4558P + U2 National Semiconductor LM308AN + U3 National Semiconductor LM308AN
You can also order custom editions from the Expandora.net website where you can select different preferred components parts from among :
TI RC4558P, TI OP07DP, National Semiconductor LM308AN/N, Motorola LM308AN/N, Russian KR140UD1408, and TI TL071CP Opamp chips.
I went for the above middle LM308 option which is supposed to deliver slightly warmer and creamier output versus the standard OP07 version. That pedal landed last Friday, and I’ve been putting it through its paces since then.
This is closest to the former 2000R original edition which was the first with the external switches, while the core circuit makeup harks way back to the very original Biixonic Expandora variety which was first releases back in 1995 and soon after became a major part of ZZ-Top frontman Billy Gibbon’s core tone.
I hadn’t realised until relatively recently that the most authentic of Expandoras used the same LM308AN/N chips so sought after in the Rat Distortion pedals too. In fact these latest Expandora pedals supposedly have all the same core components as the original Bixonic ones, with just a few modern enhancements for more regular power supply and better signal-to-noise-ratio. Some enhancements have also been made to create a thicker, less buzzy tone. Core to the tone-creation of the circuits are 3 Opamps - typically a RC4558P followed by 2 further cascaded LM308AN/N types. Key also are a single PNP 2N3906 Silicon Transistors, 4 x 1N914 Silicon Clipping Diodes, and an H11FR optocoupler.
Customisable Socketed Opamps
Another innovation here alongside those circuit tweaks and enhancements are that if you pop the back plate off the pedal - you can see that it's a reverse PCB design - with most of the components facing away from you - while you do have access to the 3 main Opamps - which are all socketed for easy replacement and experimentation.
Meaning that you can slot it any number of other similar sized Opamps - to see which combination gives you your preferred results - of course if you're willing to experiment.
I'm generally a big fan of socketed circuits and wish builders would do more of that, while it doesn't always make sense - as you often need further components and biasing to achieve the right sort of results. With similar slew-rate opamps though you should have quite a broad remit for suitable alternative opamps!
I think I read that the transistor was socketed also - while you need to somewhat dismantle the pedal to be able to access that - as it's on the other side of the board.
The Controls and The Tones
So we have pretty standard Expandora controls of Level, Tone and Gain knobs, and those two toggle-switches which combine to cascade the Opamps in different configurations.
Weirdly the orientation has changed for the core toggle-switches to Right-to-Left versus the typical Down-Up of Expandoras past - not sure why that was done here - as on the Vintage and Custom editions those Expandoras seem to have maintained the classic vertical arrangement. Also there is a legend / guide on the left-side of the pedal which is weirdly oriented horizontally rather than in the same plane as the actual switches - while the function of the switches is pretty much the same :
- →→ = Crunch
- ←→ = Overdrive
- →← = Distortion
- ←← = Fuzz / Forbidden Mode
I find the Crunch and Overdrive modes particularly satisfying - the Distortion gets quite a bit denser and slightly darker and more compressed, and the final Fuzz mode sounds rather more choked than on my 2000R - which still maintains that enticing fuzz elasticity. The trick with Exapandoras for circuit designers is to maintain that looser more elastic texture right through the 4 different stages of cascaded distortion - while the JHS Kilt is relatively Dark throughout its progress, and this new Expandora is slightly more throttled at the higher levels than I would have liked. Of course it also matters where you set the 3 knobs - as if you crank those too much - they will tend to make the texture and timbre rather more dark and dense.
I currently have my dials set to 3 o'c for Level and Tone, and 12 o'c for Gain. And I tend to live mostly on the first two modes, occasionally venturing into level 3 distortion - while I'm not sure I entirely like the 4th Fuzz mode here - I find it much more satisfying on the 2000R equivalent setting.
Of course my good friend Guillem Vilademunt of Decibelics fame is busy creating his own The Reverend Mini Clone of this famous circuit - using a rotary dial selector - indeed like my good friend Vitalii Bobrov does for his Drunk Beaver Bloom - which is another excellent clone with additional clipping options. Once The Reverend is out I will do a 5-way between my original Bixonic Expandora 2000R, JHS Kilt V2, Drunk Beaver Bloom, Expandora Squared, and of course Mini Reverend. I really like each of the varieties I have at the moment - where each has its strengths - and probably where the best realised Forbidden Mode to date is on the 2000R.
The Expandora Squared is currently on the board in slot #12 - where it will likely get an extended run before The Reverend gets its innings toward the end of the year.
As I mentioned at the top - you can get 3 different editions currently from the Expandora Reverb.com Store - where I really recommend the LM308 variants for their extra creamy and warm delivery. While I feel that there is some component addition required to get the most out of the 4th mode - possibly a further LED Diode would improve things sufficiently.
Any of you thinking of snagging a new Expandora?
Demos
