Sony MCI JH-110

The Sony MCI JH-110 is a highly regarded, professional-grade open-reel tape deck, originally developed by MCI (Music Center Incorporated) and later manufactured under the Sony banner after the company acquired MCI. It was widely used in professional recording studios for mastering, mixing, and as a multitrack recorder.

Transport and Tape Handling

The JH-110's transport mechanism is one of its most notable features, engineered for stability, precision, and reliable tape handling.

• Capstan Drive: It utilizes a 3-speed quartz-controlled transport system, which ensures highly accurate and stable speed control.3 The drive is completely solid state with high-response DC torque motors, meaning there are no transport relays.

• Tape Speeds: Standard operating speeds are typically 7.5, 15, and 30 inches per second (ips), with alternative low-speed options available on some models (e.g., 3.75, 7.5, and 15 ips).4

• Speed Control: Includes variable speed control (typically $\pm 20\%$) and the ability to lock to an external reference (e.g., $19.2 \text{ kHz}$ or $\pm 5 \text{ VDC}$ control signal) for synchronization.

• Tape Tension: The deck features a constant tape tension system, servo-controlled for both the supply and take-up reels, maintaining consistent tension across all speeds and reel sizes (e.g., $\pm 14 \text{ oz}$ for the JH-110C-8).

• Manual Velocity Control (MVC): A touch-sensitive "joystick" allows the operator to precisely control the tape's motion and speed during fast wind, rewind, and cueing, which is critical for tape editing.

• Editing Features: It includes specialized modes like "Paper Basket" (tape dump mode) and "Hand Spool" (low brake force for manual reel movement). The head assembly is designed for easy editing, with no obstructions or tape gates.

Configurations and Audio Electronics

The JH-110 was designed to be modular and highly adaptable to different studio needs.

• Formats: It was available in a variety of configurations, including:
  1/4-inch tape: Mono, 2-track (stereo, often wide-track for mastering).
  1/2-inch tape: 2-track, 4-track.
  1-inch tape: 8-track (specifically in models like the JH-110C-8).

• Electronics: The audio electronics and transport controls are often 19-inch rack mountable and feature a highly modular design for easy servicing, with individual circuit boards for Reproduce, Record, Bias/Erase, and I/O functions.

• Transformerless Design: The electronics are predominantly transformerless (though transformers were an available option for earth-free or DC isolation), contributing to improved frequency response, signal-to-noise ratio, and transient response.

• QUIOR: Features MCI's proprietary "Quiet Initiation of Record" (QUIOR) design, which uses a timed bias ramp to ensure noiseless, gap-free record punch-in and punch-out.

• Equalization and Bias: Provides separate equalization (EQ) and bias controls for all three tape speeds, along with switchable NAB/IEC (or AES for 30 ips) standards for maximum flexibility.

Technical Performance (Typical for JH-110C-8 at 30 ips, AES)

Tape Speeds: 7.5, 15, 30 ips (selectable) Quartz-controlled

Frequency Response: 40 Hz - 28 kHz  

Signal-to-Noise: 70 dB (A) weighted

Wow and Flutter: <0.015 DIN weighted

Harmonic Distortion: <0.35%

Remote and Synchronization

The JH-110 was built to interface seamlessly with other studio equipment, which was crucial in the era of early automation.

• Autolocator: Often equipped with the MCI AutoLocator III (standard on later models), a microprocessor-controlled remote with features like 10 memories and a return-to-zero (RTZ) function.7

• Synchronization: It was fully compatible with synchronizers like the MCI AutoLock, which was a SMPTE/EBU time code generator/reader/synchronizer, allowing the machine to be locked as a "slave" with high accuracy (within $50 \text{ microseconds}$) to other tape machines or video devices.