User Manual

WWW.GOLDENAGEPROJECT.COM
I
Vintage Style Preamp
for the 500 Series rack format
PRE-573
INTRODUCTION
Congratulations on choosing the Golden Age Project PRE-573 microphone preamplifier!
The PRE-573 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 over the one delivered by modern units, a
situation that is even more obvious now when music is recorded with clean sounding digital audio equip-
ment.
The circuit used in the PRE-573 is similar to the preamp section in the classical 1073 module with a cor-
responding 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 on the mic input is 80 dB, enough to handle passive ribbon mics with quiet sound
sources.
- The total gain range goes from -15 to +80 dB. The 10 – 70 dB range 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 25 dB and the input impedance increased to about 15 kohm.
- Switchable phantom power with a LED indicator.
- A flexible front panel instrument input for any sound module, 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 electric instrument. The Passive DI input mode is usually more suited for injecting
active units like sound modules.
- 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 can be activated by remov-
ing a jumper at the back of the module.
- Phase switch.
- Selectable AIR equalizer adds a small boost above 10 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.