Drunk Beaver's 17th Pedal Drop is the Rivne OTA Compressor based on the classic DynaComp and Ross circuits and their Japanese derivations

Rivne Compressor (fun naming - as the Rivne city name could be translated as ’Flat’). It’s Vitalii’s take on classic Dyna Comp / Ross Compressor circuits with some necessary mods : clean signal blend, better high impedance input buffer, must-have attack switch (classic / shorter / longer), and a tone control to get back the highs usually lost due to compression itself.

A few interesting design choices here. After much research Vitalii found that Japanese versions of that classic circuit (from Yamaha, Korg, Guyatone etc.) and the Marshall ED-1 all have a higher bias - allowing it to work on higher level signals with less distortion compared to the DynaComp. Another important change was the point at where the Compression engages. DynaComp takes it from the full wave rectifier splitter, which is not optimal, as it might introduce distortion from the rectifier to the pedal’s output. Most likely back in the days this was an efficiency / economy-related decision, so an additional buffer was added for compressed signals to be taken directly from the amplifier stage. Japanese brands also did this kind of modification, but a bit differently.

A final minor and experimental design choice was to use a transistor array IC instead of separate transistors. The benefit from this is that the transistor’s array is a matched set, coupled physically on the same silicon.

So the Rivne Compressor harnesses the best aspects of each of those inspiration circuits and then refines and improves things further.

Controls : Mix, Tone, Compression, Level, Attack : classic / shorter / longer

If you’re fans of classic OTA compression - then this is a much-improved and evolved version of those early classics.

The Rivne OTA Compressor is available right now on the Drunk Beaver Reverb.com Store for $150 plus shipping and tax. There will only be 20 units of the Rivne.