500-Series 2254 Vintage Style Compressor

US Price: $429

The COMP-554 MK2 is a one-channel vintage style compressor for the 500-format. The signal path uses only discrete components like resistors, capacitors and transistors. The input and output are transformer balanced and the unit also uses a third interstage transformer.

This is the way audio components were built before integrated circuits became available. IC´s are small and cheap and they are widely used in most modern designs. It is clear though that audio components built with modern technology does not always provide the best perceived sound quality or character that the modern user desires.

On the contrary, the subjective sound quality delivered by vintage equipment is often preferred over the one delivered by modern units. This is the reason why so many vintage audio components are cloned and produced again and also why the vintage originals are often very expensive on the second hand market.

The class-A circuit used in the COMP-554 MK2 is similar to the one in the classic 2254 compressor that was designed in 1969. It quickly became a legend due to its totally unique sound character that is warm, smooth, sweet and musical.

These characteristics have been heard on countless recordings through the years and it is a versatile sound that works very well on many sound sources and in many genres. The essence of this sound is now available at a surprisingly low cost, making it available to nearly everyone.


  • Vintage style electronics. No integrated circuits in the signal path.
  • Based on a classic diode bridge design.
  • Transformer balanced input and output.
  • Prepared for a Carnhill transformer upgrade (standard in the Plus version).
  • Flexible control range for threshold, ratio, attack and recovery.
  • All controls except the gain make-up one are stepped.
  • Three selectable sidechain fi lter frequencies.
  • Three fl exibel sidechain options; Internal, Insert and External.
  • The external sidechain I/O is electronically balanced @ 4dBu and appears on the right slot rack connections.
  • Separate switches for hardwire bypass and compression out.
  • Two insert connectors for inserting the EQ-573 in the main audio and/or sidechain signal path.
  • Meter selectable for output (two reference levels, +4 and +12 dBu) and gain reduction.
  • Possibility to link two units for stereo operation.
  • Three position Air EQ switch, Flat, +3 or +6 dB @ 30 kHz.
  • Two position output termination switch for different tones.
  • A soft start circuit that ramps up the supply voltage slowly (about 10 sec.) to avoid a power-on current surge.
  • A great sound that suits most sound sources and genres.