The COMP-554 is the 500 series rack version of the COMP-54 MKII with some additional features.
The COMP-554 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 doesn´t 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 prefered 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 is similar to the one in the classic 2254 compressor that was designed in 1969. It quickly became a legend due to it´s 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.
- The output is transformer balanced and fully floating and can drive a 600 ohm load up to level of about
- 28 dBu.
- Maximum gain in MIC mode is 80 dB, enough to handle passive ribbon mics with quiet sound sources.
- The total gain range goes from -10 to +80 dB. The 20 to 70 dB range (in MIC mode) is handled by a turn switch and a toggle switch selects an additional 5 or 10 dB gain.
- Switchable impedance on the mic input, 1200 or 300 ohms, will change the tone of many mics.
- The input can be configured to accept line level signals by another switch, the level is then lowered by about 30 dB and the input impedance increased to about 10 kohm.
- Switchable phantom power with a LED indicator.
- A flexible front panel instrument input for electric guitar or bass that can be selected between a high impedance Active or a mid-Z Passive mode. These two DI-options makes it possible to get different tones from instruments. Mains connected sound modules or other signal sources should be connected to the MIC/LINE input of the 500-rack, unless they have a fully floating, transformer balanced output stage.
- The output level control makes it possible to make fine gain adjustments and also to overload the main gain stage(s) for more character and then lower the signal to a suitable level before the output stage.
- Insert jack for inserting Golden Age Project 500 Series effect units. The insert is activated by removing a jumper at the back of the module.
- A soft start circuit that ramps up the supply voltage slowly (about 10 sec.) to avoid a power-on current surge.
- Phase switch.
- Selectable AIR equalizer adds a boost of about 6 dB centered at 30 kHz.
- A simple but effective signal and overload indicator is offered by a single LED that starts glowing red at about +4 dBu and then increases its intensity up to the maximum output level.
- Tantalum capacitors in the signal path.
- Selectable 600 ohm Output Termination at the back of the module.
- Circuit board star grounding scheme.
- A solid build quality that will last many years of normal use.