You are here

Modular Interview: Andrew Ostler

Expert Sleepers By William Stokes
Published June 2024

Andrew Ostler of Expert Sleepers.Andrew Ostler of Expert Sleepers.Photo: Viktor Snicarev

Expert Sleepers’ Andrew Ostler gives us a blow‑by‑blow account of the thinking behind his new analogue modules [reviewed in SOS June 2024 issue].

On Pandora

Pandora’s a bit of an odd one. The germ of the idea was that of using a CMOS inverter IC as a high‑gain analogue amplifier, as in the classic EDP Wasp’s filter, but here I’ve done it with discrete power MOSFET transistors instead of the logic chip. These form a band‑pass filter, much like that in an 808 kick‑drum circuit, which is why Pandora has that switch to drop the frequency range. And then of course it has vactrols for extra flavour. I’ve made some wild rhythm tracks by feeding Pandora noise and a load of rhythmic CV modulation.

On Cicely

The Octavia pedal is a particular favourite of my long‑standing collaborator, Mike — we have a band called Darkroom. As with many of these vintage ’60s pedal designs, it’s fundamentally a really simple circuit, but of course not voltage‑controllable. So the challenge here was to make it CV‑able and therefore useful in a modular context. I love how this module adds grit to the sound. So many great electronic timbres are low‑pass filtered — and who doesn’t love a classic VCF? — but that can leave them lacking in top end.

On Aloysius & Amelia

In a wonderful bit of serendipity, there are two adjacent ‘A’s in the naming scheme for these modules. Aloysius took the core of Amelia and became something inspired by the EMS Synthi’s trapezoid generator. It’s an extremely flexible source of modulation, especially in ‘free‑running’ mode when controlling all the various stages with CV.

Amelia was designed to be particularly useful in a sequencer‑driven patch, where you often have trigger pulses flying about but don’t have or don’t want to worry about an actual gate to define the note length. It generates its full envelope shape from a trigger, even if the attack is quite slow. It excels particularly at ‘plucky’ sounds, where you have a fast initial decay and then a longer ‘ring,’ not unlike that of striking a low‑pass gate — the ‘Buchla Bongo’!

On Otterley

It was becoming apparent that this analogue range had almost become a complete ‘system’ by itself, which was never really the intention. The one thing lacking in such a system was LFOs, so the Otterley satisfies that need. The idea of ‘spread’ is one I’ve used many times in the past, going right back to my VST plug‑in products. It’s a really convenient way of controlling a number of things at once with one parameter. There’s a lot of fun to be had with Otterley by patching it for self‑modulation.