Zorx Electronics
Pandora - Expert Sleepers

Pandora - Expert Sleepers

by Ian Rapp

Continuing with their Cocteau Twins Treasure theme, Pandora is the latest all analog module from Expert Sleepers. It’s obvious that the title of the song, the fifth track—hence the fifth module in this series—was an inspiration for the functionality of this module as Expert Sleepers Pandora really does open up a box of utility as it’s a bandpass filter with manual and CV controls over the high and low frequency corners [Alpha for the LPF and Beta for the HPF], and a MOSFET transistor-based distortion processor with manual and CV control over the gain amount, which in effect can be used as a VCA as well. There’s also control over filter feedback amount and a Mix control that can be modulated with CV.
Jumpers on the PCB allow the Mix to be configured to either have the halfway point of the control where the output is 50% wet and 50% dry, or to have the halfway point be 100% wet and 100% dry. It’s an interesting detail and in the latter configuration when the control is below halfway the dry remains at 100% but the wet signal wet fades out when the control moves CCW. The opposite happens as the control moved from the halfway point to fully CW, with the wet signal being 100% and the dry fading out. This can be useful, such as when you bring the filter into the dry signal to dirty it up a bit, but want to retain the low and mid frequencies. I kept mine on the factory 50/50 setting throughout most of my initial testing. A Low/High switch controls the range of the filter response and a mono input and output round out Pandora's features.
When I first racked up Pandora, I did it blindly without checking out the manual and didn’t know exactly what it was. Granted, I was pretty clued in to most of it [Distortion, Mix, Feedback are all pretty easy to decipher] but I didn’t know what the Alpha and Beta were for and so I just patched some CV into all of the CV inputs, an audio rate triangle wave into the Input, and twisted things around a bit. What I got was a pretty cool drone-y rhythm track. Tweaking the knobs a bit and I would lose the signal, distort it, get some squeals, etc., and it wasn’t long before it was time to check the manual to get some secure footing.
After confirming that I was dealing with filtering of some sort in concerns with Alpha and Beta, I finally started to know what I was doing and started utilizing the bandpass functionality of Pandora. With a pretty tweaked static signal coming out of the Xaoc Devices’ Sofia into Pandora and the bandpass with a pretty minimal thoroughfare for frequencies based in the middle of the frequency range, alternating LFOs between the CV ins of the two had my sound at the frequency cutoff for each end alternating between 80s video game lasers at the high end and bit-crushy mid-frequency kick drums at the low with a constant glitchy drone as the Gain was set at 2:00 and being fed a square wave. Minute adjustments of the knobs yielded completely different sounds and modulation affected audio lengths as well, as the modulation would veer off the cutoff and into audio purgatory. Tweaking the Feedback [even though it too was being modulated with a smooth random LFO] sounded like a dying capacitor the further CW I got. It was interesting working like this, and it struck me at how you can create really great rhythms via this method of modulating the Alpha and Beta simultaneously with various LFOs and envelopes.
One of the great uses for any tone-sculpting module is for parallel processing, and Pandora shined here, when I would mult a dry signal and blend the Pandora’s signal with the original at my mixer. In the studio this is something I do a lot with mixed drum busses, and with bass when I want to add some girth to the bass at specific frequencies, but it isn’t something I do so much in modular, but diving into it, and running the output of Pandora in this manner through a modulated VCA, the drums would have Pandora’s output mixed in along with the dry drum track to give some life, some humanity to the rhythm, adding some dynamics to this aspect of my patch. Again, this is something I sometimes lack—this changing of the rhythm—not in terms of beat, but sound. Sure, I'll do the filter sweep thing, or mute the kick or something at various times, but having the drums change tone via CV like this added a nice dimension, some variability to the drum sound, and made it less predictable. I then moved onto modulating the VCA at audio rate and it brought about some tinny ring-moddy highlights. Nasty stuff, really, and I had one instance of this using a mutated square wave output on Loralei—the Expert Sleepers VCO in this line of modules—and it was glitchy, fuzzy, busted up sounding…it was awesome. When I muted the Pandora processed track and only had the original dry signal at the mix out, I looked up and it was twenty minutes later and the sun had set. Is that a sign of something or what? Bring on the darkness, I say!
There are Vactrols used in Pandora that are in the filter section and it’s interesting to find when tweaking or patching/unpatching CV into these, that the lag time of the circuit would sometimes take a second to re-calibrate. Sometimes the adjustments were very minute, so it could just be that it wasn’t so much recalibrating as it was that I had ever so slightly moved the control to where it made a larger change than the movement would imply, and that’s the thing with analog: you need to enjoy it in real time, in the moment, as change can occur quickly, at any time, and for any number of reasons. Like having clumsy fingers. You gotta appreciate it while it's there, staring you in the face.
There’s a lot of interaction with the settings where tweaking one parameter slightly would go a long way, especially when it came to the distortion and feedback. Pandora can self-oscillate so there were times when my input signal would get buried under a wobbly self-oscillation and I'd have to back off the feedback a bit to regain some signal consciousness. It was really fun finding the sweet spots—of which I found a lot—in Pandora's box of tricks.

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