W W W . G O L D E N A G E P R O J E C T . C O M
I
Vintage Style Preamp
for the 500 Series rack format
PRE-573 MKII
INTRODUCTION
Congratulations on choosing the Golden Age Project PRE-573 MKII microphone preamplifier!
The PRE-573 MKII is a one-channel vintage style microphone, line and instrument preamplifier. The signal
path uses only discrete components like resistors,
capacitors and transistors. The microphone and line input
and the line output are transformer balanced, using two different transformers, each one optimized for its
purpose.
This is the way audio components were built before integrated circuits became available. The subjective
sound quality delivered by vintage equipment is often prefered to the one delivered by modern units, a situa-
tion that is even more obvious now when music is recorded with clean sounding digital audio equipment.
The circuit used in the PRE-573 MKII is similar to the preamp section in the classical 1073 module with a
corresponding sound character that is warm, punchy, sweet and musical. These classic characteristics have
been heard on countless recordings through the years and it is a versatile sound that works very well on
most sound sources and in most genres. The essence of this sound is now available at a surprisingly low
cost, making it available to nearly everyone.
FEATURES
- 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.
