GOLDEN AGE PRE73 MK3 Microphone preamp

The PRE-73 MKIII is a one-channel vintage style microphone-, line- and instrument preamplifier. The signal path uses only discrete components like resistors, capacitors and transistors. The in- and output is 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 circuit used in the PRE-73 MKIII 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 intergrated circuits in the signal path.

• Maximum gain in MIC mode is 80 dB, enough to handle passive ribbon mics with quiet sound sources.

• GAIN switch range 20 - 80 dB. GAIN/LINE mode switch, gain is reduced by 30 dB in LINE mode.

• Selectable two position high frequency AIR boost eq, 3 or 6 dB @ 30 kHz.

• Selectable 6 dB/octave two frequency high pass filter at around 40 (HP1) and 170 Hz (HP2).

• Tantalum capacitors in the signal path.

• Switchable impedance in MIC mode, 1200 or 300 Ohms, will change the tone of most mics. The input impedance in LINE mode is 10 kohm.

• Switchable phantom power and absolute phase.

• A high-impedance instrument input for any sound module, electric guitar or bass.

• A simple but effective 4-step LED output level meter.

• 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.

• Combo XLR/TRS input jack and separate output XLR and TRS jacks for flexible connections.

• Insert jack for inserting EQ´s and other units.

• Selectable 600 ohm output termination.

• The pcb is prepared for the Carnhill input transformer.

• External power supply to avoid interaction with the audio circuits and transformers.

• A solid build quality that will last many years of normal use.

The MKIII has the following new features compared to the MKII:

• Tantalum capacitors in the signal path.

• Selectable two position high frequency AIR boost eq, 3 or 6 dB @ 30 kHz.

• Selectable two frequency high pass filter, 6 dB/octave at 40 or 170Hz.

• The pcb is prepared for the Carnhill input transformer.

• Revised and less complicated GAIN switch with a separate switch for MIC/LINE selection.

• All GAIN settings can also be used in LINE mode .

At PreSonus, weʼve been designing preamps for a long time, and we always focus on audio quality first. So when we decided to upgrade our popular TubePre V2, we focused on improving an already high-quality sound—without jacking up the price. Like the originalTubePre, the new version is a fully professional tube preamp, with a dual-servo (no capacitors) gain stage that lets you boost the program signal to smoking hot levels without significantly increasing the background noise. Discrete components and high-voltage operation offer dynamic range and detail not found in other single-channel tube preamps in its class.

Housed in a rugged case, the TubePre V2 rear panel sports separate unbalanced, ¼” instrument and balanced, XLR mic inputs and unbalanced ¼” and balanced XLR line outputs. Weʼve included all of the extras you need for professional operation including a high-pass filter, phantom power for condenser mics, polarity reverse switch, and a backlit VU meter.

The PRE-73 DLX is a one-channel vintage style microphone-, line- and instrument preamplifier. The signal path uses only discrete components like resistors, capacitors and transistors. The line and microphone input and the line output are transformer balanced, using three 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 equipment.

The circuit used in the PRE-73 DLX 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 intergrated circuits in the signal path.
- Maximum gain on the mic input is 80 dB, enough to handle passive ribbon mics with quiet sound sources.
- Gain range on the Line input: -20 to + 10 dB.
- Switchable impedance on the mic input, 1200 or 300 Ohms, will change the tone of most mics.
- Switchable phantom power and absolute phase.
- A high-impedance instrument input for any sound module, electric guitar or bass.
- A simple but effective 4-step LED output level meter.
- The output level controls 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.
- Combo XLR/TRS input jacks and separate output XLR and TRS jacks for flexible connections.
- Insert jack for inserting EQ´s and other units.
- External high power power supply to avoid interaction with the audio circuits and transformers.
- A solid build quality that will last many years of normal use.

The PRE-73 DLX has a number of improvement and new features compared to the PRE-73 MKII:
- Tantalum capacitors in the signal path.
- Selectable 1073-style high pass filter, 50Hz, 80Hz, 160Hz and 300Hz.
- Output Attenuator -7, -14, -21 and -28 dB (located after the output transformer) allows overdriving the output stage and the output transformer for added character by lowering the output signal to a suitable level.
- The circuit board is prepared for Carnhill Mic and Line transformer and high pass inductor.
- The Insert jack can be switched in/out from the front panel. An internal jumper can select that the Insert jack always has an output signal.
- Switchable 600 ohm Output Termination and Ground Lift on the back panel.
- Selectable Active or Passive DI input and selectable input impedance in active mode, Hi Z or 100 kohm, by internal jumpers.
- The DI can signal can be selected to pass or bypass the mic input transformer by internal jumpers.
- Relays are used to control internal switching for DI input, Phantom power, Mic Low Z, Insert and Phase for shorter circuit board signal paths. The relays are controlled by front panel switches.
- Revised gain switch for added headroom.
- Circuit board star grounding scheme.
- Revised power supply with separate regulators for the audio circuits and relay and LED circuits.

The U5 high-voltage DI-preamp combines a unique passive tone selector with a variable
gain preamp and filter. The high input impedance accepts a wide variety of signal levels
and instruments from acoustic guitars to high-output active bass guitars and keyboards.
The U5 direct box is loaded with sonic character and user features professionals demand.

U5 FEATURES
Pure Class A, 100% discrete design
Smooth musical detail and sonic excellence
Variable gain preamp to +30dB.
Dual microphone and line outputs
Hi-Z   3,000,000 ohm input impedance
Very low noise -100dB
High headroom +30dB
Six tone bank selections.
DC coupled Class A output for superior bass
High cut switch eliminates noise
LED active signal indicator
Headphone monitor output jack
Low distortion less than 0.5% THD and IMD
High level 400 watt speaker input
Active to thru selector - ground isolation switch
100% discrete power supplies for audio path
Internal toroidal power supply for low noise
Long lasting, stainless steel hardware
 
SONIC EXCELLENCE
The Avalon U5 Pure Class A instrument DI & preamplifier is the most powerful direct box
available today.  Designed to optimize absolute signal integrity and musical performance,
the U5 includes many features and sonic excellence unequaled by lesser designs. The
U5 is ideal for bass guitar and acoustic instruments, electric guitars, keyboards, synthesizers
and low output pickups. 
Features include state-of-the-art, high input impedance input stage for zero load effect on
sensitive pickups and keyboards, 100% discrete, Pure Class A signal amplifiers, practical
user features and rugged hardware designed to deliver true high performance audio for many
years. 
DESIGNED FOR DEEP & CONTROLLED BASS
Avalon U5 DI-preamps have been in use around the world since 1995. They have found their way
into the world's leading musicians rigs and recording sessions and been featured on thousands
of the best selling (and sounding) albums and live performances.
MINIMUM SIGNAL PATH DESIGN
The U5 includes a variable gain Class A preamplifier to boost low level pickup signals and a high
level speaker input for capturing the live sound of the instruments amplifier. Six passive tone-EQ
curves are also included to enhance a variety of acoustic and electric instruments. A high-cut switch
eliminates unwanted acoustic pickup and high frequency noise, while a  headphone monitor amp
has been included for personal listening. Twin DC coupled Class A output amplifiers drive both low
level microphone preamp inputs and high level +4dB inputs for direct to tape recording or processing.
The active-to-thru switch selects either the instrument input directly or sends the boosted-equalized
signal to the amplifier via the front panel jack. A ground isolation switch eliminates any possible earth
loop or AC buzz problems with complete safety.

U5 SPECIFICATIONS
Circuit Topology:  100% discrete, high-voltage Class A 
Gain:  Switched 3dB steps, maximum gain +30dB 
Input Impedance:  3 ,000,000 ohm unbalanced (single ended) 
Maximum Input Level  +24dBu unbalanced, 400w speaker input 
Output Connectors (2):  XLR type, pin 2 hot electronic balanced 
Maximum Output Level (Class A):  +30dBu DC coupled, balanced 600 ohms (mic and line out) 
Headphone Output:  0.5w into 600 ohms 
Noise 20kHz Unweighted:  -100dBu minimum gain position 
Distortion THD, IMD:  0.1% at +10dB 
Frequency Response, -/+0.5dB:  5Hz to 100kHz 
Frequency Response, -3dB:  1Hz to 500kHz (input band limited) 
High Cut Filter:  -3dB at 8kHz minimum phase design 
Tone Selector:  Six position rotary switch, all passive filters 
AC Power:  Internal toroidal AC supply 
Dimensions:  8.5 x 3.5 x 12 in (216 x 88 x 305mm) 
Weight-Packed:  12lbs (5.4kg) 
Rack mount kit (1) RM-1:  Single U5 19 inch rack mount kit (holds one half rack unit) 
Rack mount kit (2) RM-2:  Dual U5 19 inch rack mount kit (holds two half rack units)