PRESONUS EUREKA -SINGLE CHANNEL PREAMPLIFIER COMPRESSOR and EQUA

The EUREKA Pro Recording Channel

The Eureka is a professional recording channel strip containing a discrete class A
transformer-coupled microphone preamplifier, compressor, and three-band parametric
equalizer. The microphone preamplifier features variable input impedance so that the
Eureka can be matched and "tuned" for all types of microphones and recording
applications. The Class A transformer-coupled microphone preamplifier also features
"SATURATE" which adjusts the drain current on the input FET amplifier to simulate of
the effects of tape saturation and tube "warmth“.
The Eureka's ultra fast compressor has both soft and hard knee compression as well
as a separate make up gain stage and hi-pass side chain compression to deliver hard
pumping to ultra transparent compression and everything in between. The Eureka's three-
band fully parametric EQ gives you variable Q (bandwidth) on each band as well as an
EQ pre COMP switch to put the EQ before the Compressor in the signal path. The equalizer
has overlapping frequency selection on each band for total tonal control and shaping.
The Eureka is loaded with microphone, line and instrument input so you can use it as a front
end preamplifier for recording with microphones, guitars, keyboards, synths as well as a
compressor/equalizer on a single channel during mixdown. The Eureka also has balanced send
and return jacks so that you can insert your favorite outboard processor before the compressor/
EQ to further enhance and customize your sound.
An optional 24 Bit/192kHz digital output card (AD192) is available for the Eureka to further
optimize sonic performance. The Eureka's AD192 digital output card is loaded with both SPDIF
and AES/EBU outputs, word clock I/O as well as a balanced TRS line input so that only one
output card is necessary when using two Eureka's in stereo or dual mono situations.
The Eureka gives you the sonic performance and control you need in the real-world to produce
professional quality audio that you, your customers and your fans deserve!

 Features
? Class A High Headroom Transformer Coupled Microphone Preamplifier
? Variable Microphone Input Impedance
? Variable SATURATE control (simulates tape saturation and tube warmth)
? Fully Variable Compressor with Hi-pass Side Chain
? Three Band Fully Parametric Equalizer
? EQ Pre or Post Compressor
? High Headroom Output Section
? Very Low Noise Design
? Internal Power Supply
? Transparent, wide range performance
? Optional 24-Bit/192k Digital Output Card (AD192)
  
Technical Specifications
Channels One
Dynamic Range >115dB
Headroom +22dB
Frequency Response 10Hz to 50kHz
Internal Operating Level 0dBu = 0B
Microphone Preamp
Input Impedance, XLR Input 1.3k Ohms
Input Impedance, Line Level Input 10k Ohms
Connectors Neutrik? Combo
Microphone Preamp
Gain +12dB to +52dB
Noise Floor -112dBu (+12dB gain)
EIN -127dB
THD + Noise (0% saturation)

The CPR12 is an easy to use, flexible and multifunctional 10 channel pre-amplifier. Six of these input channels are selectable between Mic / Line level and equipped with a 3 band tone control. The first two can be switched to priority and phantom power. The other four channels are direct line inputs.

Every input channel has its own gain and fader volume control with PFL button which makes it possible to pre-listen each input or output channel with the built-in pre-listening speaker, and can be routed to one or both output channels. This makes the CPR12 a full two-zone system.

Other present features are a priority input, a recording output, separate sub-out channels and the 24 V DC emergency power connection. This last feature makes it possible to power the CPR12 with emergency power when the main power is shut down. In this case, the priority input will automatically mute all input signals, and a evacuation message will be announced. The steel 19" housing has a height of 2 HE.

• 10 audio input sources
• 6 Mic / Line inputs with 3 band EQ
• 4 Direct Line Inputs
• Fader volume control
• Two output zones
• Built-in pre-listening speaker
• Priority input for emergency situations
• + 15 V DC Phantom power
• Works on 24 V DC emergency power
  

• Model Name / Type: CPR12 / 10 channel 2 zone pre-amplifier
• THD+N:
• Signal/Noise: > 90 dB
• Frequency Response: 20 Hz - 20 kHz
• Phantom Power: + 15 V DC
• Emergency Power: + 24 V DC
  
• Power Supply: 100 - 240 V AC / 50 - 60 Hz
• Dimensions (W x H x D): 420 x 88 x 320 mm

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.

• Maximum of 66 dB of gain, in eleven discrete steps
• Dynamic range exceeding 120 dB
• 10 Hz to 50 kHz audio bandwidth
• High immunity to RF interference
• High current line output driver
• Transformer-balanced input and output
• Extended range peak limiter via dual opto-isolators makes preamplifier virtually "unclippable“
• Selectable 48-volt / 12-volt phantom power or 12-volt "T" power
• High-pass filter @ 80 or 160 Hz, 6 dB per octave
• Headphone monitoring of microphone audio, monitor audio, or a mix of both
• Monitor input accepts mono, balanced or unbalanced line-level inputs on 1/4-inch tip-ring-sleeve connector
• Separate level control of Monitor gain and overall headphone gain
• Split ear function via DIP switches
• Internal battery power (two-AA)
• Excellent battery life with alkaline and NiMH rechargeable batteries
• External 5-17 VDC powering (plug included)
• High-strength aluminum chassis with durable belt clip

Having had great success with the PRE-73 preamp, we have received many requests for a version for the 500 eries rack format. We are therefore happy to present the PRE-573, expected to start shipping in late September.
 
The PRE-573 is a one width module that has the sound and the features that made the PRE-73 so successful and a few additional ones.
The circuit still uses the preamp and output section from the classic 1073-module, adapted to work in the api rack format. It has a total  gain range from -15 to +80 dB. The 10 - 70 dB range is handled by a turn switch  and there is a separate toggle switch to select an additional 5 or 10 dB gain. The input can be configured to accept line level signals by another switch, the gain is then lowered by about 25 dB and the input impedance increased to about 15 kohm.
 
The input impedance of the mic input mode can be switched between 1200 and 300 ohm. Phantom power and phase reverse is also selectable by front panel switches.
 
An added feature, using the same circuit as in the PRE-73 DLX, is the active DI-input with a high input impedance of about 1,5 Mohm. The output signal from the active DI circuit passes through the input transformer for some extra character.
The DI-input is very flexible since it can be changed to a purely passive one by a front panel switch. The DI input is then exactly the same as in the PRE-73 Mk2 where the signal is feed directly into the second gain stage, bypassing the transformer and with an input impedance of about 100 kohm.

These two DI-options makes it possible to get different tones from electric instruments and the passive DI input mode is more suited for injecting active units like sound modules. 
 
A new feature is the switchable AIR mode that  adds a small boost above 10 kHz that peaks at 2 dB at about 35 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.
 
The PRE-573 has a dedicated insert connector at the back allowing it to interface with other GAP 500 modules. The insert can be activated by removing a jumper connector at the back of the module.
The second Golden Age Project module for the api 500 rack will be the EQ-573, expected to ship in November 2012. The EQ-573 consists of the inductor based high pass filter section  and the 3-band eq section from the classic 1073 module with some added frequencies. These two modules together will offer a fully fledged 1073-module in a compact format at a very low cost.
 
There is a second jumper at the back of the module that selects 600 ohm termination on the output. The standard mode is termination on, since it gives the flattest response when the PRE-573 is used with modern line inputs that typically has an input impedance of 10 kohm or more. The user can chose to remove the jumper and deactivate the termination resistor, this will increase the level above 10 kHz and create a peak in the response for an even more pronounced  "Air" effect.
The output is transformer balanced and fully floating and can drive a 600 ohm load up to level of about 28 dBu.