Golden Age Project Pre-573 MKIII

1073-style 500 series vintage preamplifier

High-quality 1-channel 500-series rack format microphone preamp, made with discrete components and independent transformers for mic, instrument, and output, equipped with a circuit inspired by the famous Neve 1073, Mic inputs with Combo connector, Line with Combo connector, and high-impedance Instrument with 1/4" TRS Jack, insert with 1/4" TRS Jack, active DI input with 1.5Mohm impedance, adjustable mic gain up to 80dB, adjustable mic input impedance at 300 or 1200 Ohms, Air mode that adds a slight boost above 10KHz and a jumper to reduce input impedance and further increase the Air effect, high pass filter 45/180Hz, phase inversion, 48V phantom power, LED level indicator, output level adjustment.

Specifications

• 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 a level of about 28 dBu.
• Maximum gain in MIC mode is 80 dB, sufficient to handle passive ribbon microphones with quiet sound sources.
• The total gain range is from -10 to +80 dB. The range from 20 to 70 dB (in
• MIC mode) is controlled by a rotary switch and a toggle switch selects an additional 5 or 10 dB gain.
• Switchable impedance on the microphone input, 1200 or 300 ohms, will change the tone of many microphones.
• The input can be configured to accept line-level signals from another switch, the level is then lowered by about 30 dB and the input impedance increased to about 10 kohm.
• A two-position selectable 6 dB/octave high-pass filter with a frequency of approximately 45 or 180 Hz.
• A flexible front panel instrument input for electric guitar or bass that can be switched between a high-impedance active mode or a mid-Z passive mode.
• These two DI options allow different tones to be obtained from instruments. Sound modules connected to the mains or other signal sources must 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 allows precise gain adjustments and also to overload the main gain stages to get more character and then lower the signal to an appropriate level before the output stage.
• Insert jack for inserting Golden Age Project and Premier 500 series equalization and effects units. The insert is activated by removing a jumper on the back of the module.
• A soft-start circuit that slowly increases the supply voltage (~10 seconds) to avoid a current surge on power-up.
• Phase switch and switchable phantom power with LED indicator.
• The selectable AIR equalizer adds an increment of approximately 6 dB centered at 30 kHz.
• A simple but effective signal and overload indicator is offered by a single LED that starts to glow red at about +4 dBu and then increases its intensity up to the maximum output level.
• Tantalum capacitors in the signal path.
• The 6.8 kohm phantom power resistors are matched within 0.1% to maintain good common mode rejection in the circuit.
• Selectable 600 ohm output termination on the back of the module.
• Star grounding scheme of the circuit.
• Solid build quality that will last many years of normal use.