Golden Age Project


1-Channel Vintage Style Compressor

The COMP-2A is a one channel vintage style Compressor / Leveler using vacuum tubes in the signal and side-chain path. The input and output is transformer balanced, using two different transformers, each one optimized for its purpose. This is the way audio components were built before transistors and integrated circuits became available.

Integrated circuits are small and cheap and widely used in most modern designs. The drawback is that audio components built with modern technology doesn't always provide the best perceived sound quality or the type of character that the modern user desires.

The subjective sound quality delivered by vintage equipment is often preferred over the one delivered by modern units, a situation that is even more obvious now when music is recorded with clean-sounding digital audio equipment.

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 circuit used in the COMP-2A is based on a classic design that was originally produced in the early 1960s and it was initially intended for broadcast applications. It uses an electro-luminescent panel and a photoelectric cell to control gain. This gives it a unique, program dependent compression characteristic. In addition, the all tube signal path and the transformers adds a wonderful and musical character to the sound.

The ease of use with only two main controls makes it very simple to achieve the desired sound. These attributes has made the original units a favorite of engineers and musicians worldwide. This classic sound is now available at a very affordable price point with the COMP-2A.

  • Vintage style all tube signal path. The tubes are fitted with grounded shields.
  • Transformer balanced input and output. Can drive almost any load, balanced or unbalanced.
  • Golden Age Project’s version of the classic optical unit using a long life electroluminescent panel and two carefully matched Silonex NSL5910 photoresistors for T4B-style electro-optical gain control with program dependent attack and release times.
  • Very simple to operate with only two main controls, Gain and Peak Reduction.
  • HF control can make the side-chain circuit more sensitive to mid and high frequency content.
  • Linear regulated low noise filament and high voltage power supply.
  • A big meter selectable to show gain reduction or output level at two different reference levels.
  • Hardwire bypass switch for easy comparisons.
  • XLR and TRS input and output jacks for flexible connections.
  • Link jack and switch for connecting to another unit for stereo operation.
  • All external controls located on the front panel.
  • Compact 2RU half rack format. Two units can be mounted with our 19-inch rack kit, the UNITE BIG.
  • A solid build quality that will last many years of normal use.
Adjusting two COMP-2A units for stereo operation
  • Connect a cable between the LINK connectors of the two units.
  • Engage the LINK switch on both units.
  • Set the MONO control fully clockwise.
  • Set the PEAK REDUCTION knob to 0.
  • Set the METER switch to +4 dB.
  • Connect a signal generator set to 1 kHz to the inputs of both COMP-2A units. Set the signal generator output level to about 1,23V.
  • Adjust the GAIN control on each unit so the outputs are equal at 0 dB on each unit.
  • Set the METER switch to GR on both units. Turn the PEAK REDUCTION knob on one of the two units until the meter reads -5 dB, both units should respond.
  • Note which COMP-2A is reading the most gain reduction. On this unit, turn the MONO control counter clockwise until both COMP-2A meters read the same value. The unit is now in calibration.
  • Bring up the PEAK REDUCTION of the remaining unit to the same numerical value to match gain reduction.
  • You are now ready to use the two units as a stereo pair. Typically the user adjusts both front panel knobs in tandem to achieve matched compression and output levels. The stereo image should remain solid and both units should compress the stereo signal equally, regardless of which side (left or right) is triggering the gain reduction.