Custom Collins 26-J Vari-Mu Tube Compressor — Thordarson / Freed Transformers, Daven & Langevin Attenuators

For sale is a Downbeat custom-built tube vari-mu compressor based on the classic Collins 26-J broadcast compressor circuit. This build was put together with a focus on preserving the character and topology of the original Collins design while using carefully selected vintage components and a few practical modifications. The result is a large, dimensional tube compressor with the unmistakable feel of old broadcast gear: smooth gain reduction, substantial transformer weight, and a wonderfully forgiving character when pushed. Tube Complement: The original Collins 26-J design calls for a 6386 variable-mu tube. Rather than using a single increasingly scarce and expensive 6386, this build uses a closely matched pair of mil-spec 6BA6 tubes for the variable-gain stage. I spent time matching and testing the pair, and I couldn't be happier with how this implementation sounds. Compression is smooth, musical, and extremely usable. The remaining tube complement includes: Closely matched pair of mil-spec 6BA6 tubes for gain reduction 6AL5 detector tube Matched pair of brand-new JJ 6V6 tubes operating push-pull in the output stage Transformers & Attenuators A major part of the sound of this build comes from the vintage iron and attenuators: Vintage Thordarson input transformer Vintage Freed output transformer Langevin attenuator Daven attenuator These are substantial pieces of vintage broadcast-quality hardware and contribute heavily to the character of the compressor. Controls: The front panel provides considerably more control than many vintage compressors while retaining a very straightforward workflow: Input Attenuator Output Attenuator Compression In / Out Variable Threshold Variable Attack Switchable Release Single / Double mode switch Meter Adjustment The combination of stepped attenuation and variable compression controls makes it easy to drive the tube and transformer stages harder while controlling the final output level. Sound: It has the depth, movement, harmonic character, and slightly larger-than-life presentation associated with vintage tube broadcast dynamics. At lighter settings it works extremely well for subtle leveling and adding transformer/tube density. Push the input harder and it becomes much more obvious, with thicker harmonics, stronger gain-reduction movement, and plenty of vintage character. It can be especially effective on: Vocals Bass Drum room microphones Drum bus Piano Acoustic instruments Mix elements that need weight and movement Parallel compression The push-pull 6V6 output stage and large Freed output transformer give the unit a particularly substantial output character. Construction: The compressor is housed in a heavy-duty rack chassis and built using traditional point-to-point / turret-style construction. Internally you'll find a mix of vintage components and modern high-quality parts selected for reliability where appropriate. The unit includes an internally mounted power supply and standard IEC AC input. Feel free to reach out with any questions about the circuit, components, controls, or operation.