Soviet American Audio Systems TYPE III MP500

The MP500 is a dual-gain-stage microphone preamp based on the preamps in Russian Recording’s vintage Sphere Eclipse Type III analog recording console. It uses newly manufactured Reichenbach 7341 microphone input and 7393 output transformers, made in the same factory using the same drawings and materials as the transformers in vintage Sphere consoles, along with two SAAS-designed DOA60 discrete op amps.

The DOA60 was inspired by the sound of the original SPA60 amplifiers used in vintage Sphere consoles. It uses thoughtfully chosen modern components to improve consistency, specs, and stability while retaining the detail, imaging, and sonic character that made the original amplifiers so special. The first amplifier handles input gain, and the second handles output gain. Together, they provide at least 83 dB of total available gain.

While the original vintage console preamps were limited to two input gain settings with an input pad, the MP500 provides 12 input gain settings on a Grayhill rotary switch, a 20 dB input pad, selectable input impedances of 300Ω or 1.5kΩ, and fully variable output level. This gives the engineer precise control over both gain stages and the ability to handle quiet and loud sources with ease. The 1.5kΩ setting reduces gain by about 6 dB depending on the microphone’s output impedance, while adding a subtle rise in the high frequencies. A selectable 20 dB boost can be added to the output stage when additional gain is required.

The MP500 also includes a dedicated active Direct Input (DI) for direct instrument recording. Unlike many other 500 Series preamps, the direct input uses a dedicated input stage inspired by instrument amplifiers of the 70s. The DI signal still passes through both DOA60 gain stages and the output transformer.

• Dual-gain-stage, transformer-balanced 500 Series microphone preamp inspired by the sound of vintage Sphere console preamps and output amps
• Newly manufactured Reichenbach 7341 microphone input transformer and 7393 output transformer, made in the same factory using the same drawings and materials as those used in vintage Sphere consoles
• Two SAAS designed proprietary DOA60 discrete op amps inspired by the original vintage Sphere SPA60 amplifiers
• 12-position Grayhill input gain control, adjustable from 20 dB to +53 dB in 3 dB steps
• Continuously variable output level
• Switchable +20 dB output stage boost
•  83dB maximum available gain
• Selectable input impedances of 300Ω or 1.5kΩ
• Passive -20 dB input pad
• 48V phantom power with red status LED
• Polarity reversal
• Dedicated active DI circuit with front-panel 1/4″ input
• 10-segment LED output meter
• Relay switching for front panel switch functions to ensure reliability
• API 2520-compatible discrete op amp footprint, swappable for other electrically and mechanically compatible 2520-format modules
• Suitable for microphones, instruments, and line-level processing

User's Manual