HLabs has announced the CL089, an analog compressor for the API 500 Series based on the compression circuitry of the vintage Studer 089 console. It combines the original design’s Pulse Width Modulation (PWM) gain-reduction architecture with additional controls and an updated output stage. Announced on November 12, 2026, the CL089 is priced at €949 including VAT, but is currently listed as out of stock on the manufacturer’s website.
Studer 089 Compression Design
Originally developed for Swiss broadcasting and classical recording, the Studer 089 console was designed for clean, neutral signal processing. Its compressor modules were among the early professional audio designs to use PWM-based gain reduction, an alternative to more common VCA, FET and optical compressor topologies.
The CL089 retains this analog compression architecture and uses predominantly through-hole components. It offers four compression ratios: 1.5:1, 2:1, 5:1 and LIMIT, along with five release settings: 100 ms, 300 ms, 750 ms, 2 seconds and Auto.
HLabs has added several features not found in the original design, including extended input attenuation and output gain ranges, a Slow Attack mode and a 120 Hz sidechain high-pass filter. The Tandem function links two CL089 units for stereo operation.
H101 Op-Amp and Lundahl Output Transformer
The output stage uses HLabs’ H101 discrete operational amplifier, a modern recreation of the A101 circuit found in the original Studer design. It is paired with a Lundahl LL1588 output transformer at the end of the compressor’s analog signal path.
The H101 is socket-mounted and uses a 2520-compatible pinout, allowing users to install other compatible op-amps and experiment with different circuit characteristics. HLabs also sells the H101 separately for use in compatible equipment.
Another distinctive feature is the gain-reduction indicator. Rather than using a conventional LED meter, the CL089 has a small incandescent bulb, reflecting the design’s vintage inspiration.
Pricing and Availability
The HLabs CL089 is priced at €949 including VAT in Europe and £830 including VAT in the UK. Its reported US MSRP is $1,059.
Although HLabs announced the module as available, its official product page currently lists it as out of stock. Prospective buyers should contact the manufacturer for information about the next production run.
The CL089 expands HLabs’ range of Studer-inspired hardware, which includes the PRE169 preamp and EQ169 equalizer. It brings PWM-based analog compression to the 500 Series format, adding another option for recording and mixing engineers interested in vintage-inspired dynamics processing.
