Introduced at the 115th AES Convention in October 2003 and commercially available the following month, the Apogee Mini-MP expanded the company’s Mini-Series alongside the Mini-Me and Mini-DAC. Whereas those products concentrated on digital audio conversion and monitoring, the Mini-MP was dedicated entirely to analogue microphone and instrument preamplification. Drawing upon preamplifier technology developed for the Apogee Trak2 and Mini-Me, the unit was designed to provide professional recording facilities with a portable, standalone front end suitable for both studio and field recording applications.
At the centre of the Apogee Mini-MP are two independent, high-gain, low-distortion microphone preamplifiers. Each channel incorporates a continuously variable gain control, allowing precise adjustment without the stepped switching arrangements commonly found on professional microphone preamps. Apogee designed the gain circuitry to permit smooth level changes during recording, avoiding the audible switching artefacts that can occur when gain is altered using conventional switched controls.
The original manufacturer documentation describes a maximum gain capability of 75dB, while the published technical specifications identify a continuously adjustable preamplifier gain range of 0 to 70dB. A separate master output control provides additional output gain adjustment from negative infinity to +6dB. This arrangement allows the input gain and final output level to be controlled independently, providing flexibility when matching the preamplifier to different recording systems and signal levels.
The Apogee Mini-MP’s analogue signal path was designed to minimise noise and distortion. Rather than employing conventional signal-path switching arrangements, Apogee used gas-filled relays for switching functions and restricted the use of capacitors in the audio path to those required for isolating phantom power from the active circuitry. This approach was intended to minimise unwanted signal degradation while maintaining the preamplifier’s wide bandwidth and low-distortion performance.
The microphone inputs are capable of accommodating signals up to +18dBu, providing considerable headroom for high-output microphones and demanding recording applications. The unit also incorporates automatically selected high-impedance instrument inputs, allowing electric guitars, bass guitars, keyboards and other instruments to be connected directly without requiring a separate DI box.
Two combination XLR and 6.35mm jack connectors on the rear panel accommodate microphone and instrument connections. The balanced microphone inputs have a nominal impedance of 1.6kΩ, while the unbalanced high-impedance instrument inputs provide 2.2MΩ, making them suitable for instruments with passive pickups as well as other unbalanced sources.
On the output side, the Apogee Mini-MP employs electronically balanced line drivers originally developed for the Mini-DAC. These circuits were designed to reproduce the electrical behaviour of transformer-balanced outputs without incorporating conventional output transformers. The design maintains balanced operation even when driving asymmetrical loads and allows connection to unbalanced equipment without the increased distortion that can occur in some electronically balanced circuits.
The output stages have an exceptionally low impedance of 25Ω and are capable of delivering substantial signal levels into a variety of loads. According to the published specifications, the Apogee Mini-MP can deliver +26dBu into a 100kΩ load, +24dBu into 600Ω and +21dBu into 300Ω. This capability allows the preamplifier to drive professional recording equipment, including systems presenting relatively demanding input loads.
One of the Apogee Mini-MP’s more specialised features is its integrated Mid-Side matrix decoder. Selected using the central three-position power and operating mode switch, this facility allows the unit to operate either as two independent preamplifier channels or as a Mid-Side stereo processor.
In Mid-Side mode, the left input functions as the Mid channel and the right input as the Side channel. The internal matrix converts these signals into conventional left and right stereo outputs, with the left output representing the sum and the right output representing the difference of the Mid and Side signals. This allows Mid-Side microphone arrangements to be decoded directly without requiring an external matrix mixer or additional processing equipment.
The Mid-Side facility is particularly useful for stereo recording techniques in which one microphone captures the central sound field and a second figure-of-eight microphone captures the difference information between the left and right sides. By adjusting the relative gain of the Mid and Side channels, the stereo width can be altered while maintaining mono compatibility. The matrix can also be used when processing suitable previously recorded stereo material.
Each microphone channel includes independently selectable 48V phantom power, a polarity reversal switch and a high-pass filter. The phantom power facility allows condenser microphones requiring standard external powering to be connected directly, while the polarity reversal switch provides a convenient means of changing signal polarity when working with multiple microphones or Mid-Side recording configurations.
The high-pass filters operate at 80Hz with an 18dB-per-octave slope, using a third-order Butterworth filter design. These filters can be engaged independently on each channel to attenuate low-frequency energy such as handling noise, mechanical vibration and unwanted bass frequencies before the signal reaches the recording system.
The front panel provides a clear indication of signal levels through two four-segment LED meters. Each channel displays signal activity at -20dB, 0dB and +6dB, together with a red clipping indicator. These meters allow input levels to be monitored directly while adjusting the microphone gain controls.
The central output control is surrounded by a blue illuminated ring when the unit is powered, while individual blue LEDs indicate phantom power operation. The arrangement of the controls allows both channels to be operated independently while retaining a shared master output level adjustment.
Unlike microphone preamplifiers that require a conventional internal mains power supply, the Apogee Mini-MP was designed to operate from an external DC source. Its power circuitry accepts voltages from 6V to 14V DC, with a specified consumption of approximately 3W. This allows the unit to operate from compatible batteries and external power supplies, making it particularly suitable for remote recording, mobile production and other situations where mains power may be unavailable or inconvenient.
The Apogee Mini-MP’s compact chassis was intended to complement other Apogee Mini-Series equipment while remaining practical for portable applications. Its aluminium-style silver front panel, distinctive purple gain controls, illuminated output knob and symmetrical layout gave it a visual identity shared with other products in the range.
With its combination of independent microphone preamplification, instrument connectivity, Mid-Side processing and flexible power requirements, the Apogee Mini-MP represented an alternative to conventional rack-mounted microphone preamplifiers of the early 2000s. By concentrating on analogue signal quality and practical recording functions rather than digital conversion or onboard effects, the Apogee Mini-MP provided a dedicated recording front end that could be integrated into a wide variety of studio and mobile recording systems.
Features
- Two independent analogue microphone and instrument preamplifier channels
- Continuously variable, ultra-linear microphone gain controls with up to 75dB total gain capability
- Integrated Mid-Side stereo matrix decoder with selectable stereo and M-S operating modes
- Automatically selected high-impedance instrument inputs for guitars, basses and keyboards
- Electronically balanced, low-impedance analogue outputs capable of delivering up to +26dBu
- Individually switchable 48V phantom power for each microphone channel
- Independent polarity reversal switches for both channels
- Switchable 80Hz high-pass filters with 18dB-per-octave attenuation
- Four-segment LED level meters for each channel, including clipping indication
- Portable, low-power design supporting external DC supplies and compatible battery operation