The AMS DMX 15-80S made a significant contribution to the development of digital delay technology, standing out for its exceptional capabilities when it was introduced. The delay times on this unit are fully adjustable, without sacrificing the 18kHz bandwidth, which remains constant regardless of the decay selected. This ensures that the sound quality remains clear and transparent, even at extended delay times, which can exceed 32 seconds across two channels. This feature set the AMS DMX 15-80S apart from many of its contemporaries, ensuring that long delay effects could be achieved without compromise.
Notably, the design of the AMS DMX 15-80S was highly modular, allowing for the integration of new technologies and techniques as they emerged. This forward-thinking approach meant that the system would not become obsolete over time, as the design could evolve with advancements in digital audio. The unit employed 15-bit digital encoding, achieved through 12-bit conversion combined with three instantaneously sweetened gain ranges of 6dB each. This resulted in an impressive 90dB dynamic range, free from the distortion problems associated with analogue compression and expansion techniques, such as noise breathing.
As part of its robust design, the AMS DMX 15-80S also included standard memory backup to ensure that entries to the microprocessor would not be lost in the event of a power failure. Both input and output levels were adjustable, allowing the unit to accommodate equipment with non-standard signal levels, a feature that provided additional flexibility in diverse setups. Furthermore, an intelligent, glitch-free pitch change option was available, capable of shifting pitch by as much as one octave in either direction, making it a versatile tool for sound design and experimentation.
The pitch shift option was enhanced by the unit’s ‘lock in’ function, which allowed for indefinite storage and playback of both delay line contents without degradation. This function, however, could be transformed into a tape loop editing system, providing further flexibility for creative uses. The ability to trigger the ‘locked-in’ audio was also a key feature, adding an extra layer of control for engineers working with dynamic sound environments.
An additional feature that expanded the capabilities of the AMS DMX 15-80S was the add-on digital reverberation system, the AMS MX15R. This add-on unit, physically identical to the DMX 15-80S, featured nine preset programmes, an 18kHz bandwidth, and a 90dB dynamic range, with typical distortion at a mere 0.03%. The unit offered independent control over variables such as pre-delay, decay times, and both high and low-frequency decay profiles, allowing users to tailor the reverb to fit their needs precisely.
Regeneration controls were provided on both channels of the AMS DMX 15-80S, with the ability to switch the input for single-line use, where channel ‘A’ fed both delay lines. A switch also allowed for the mixing of the outputs, adding another dimension to the effects available, particularly for special effects applications.
One of the standout features of the DMX range, including the AMS DMX 15-80S, was the innovative use of ‘Nudge Buttons’. These buttons allowed the delay to sweep up or down in very small steps of just 25μs, producing a virtually silent effect. A further level of control was offered by the ability to switch channel ‘A’ in or out of phase with both the original and channel ‘B’. A reset switch was included for initialising the computer, and a clear instruction was available for the computer store, ensuring smooth operation and easy maintenance.
For professionals on the move, a flight case was available for the AMS DMX 15-80S, with additional options for cases that could accommodate multiple AMS systems. This rugged design and portability made the unit ideal for both studio and live environments, where durability and ease of transport were paramount. The AMS DMX 15-80S was engineered to a high standard, consistent with the rest of the DMX range, with microprocessor-controlled front panel facilities that included programmability, repeatability, and storage capabilities not available with other forms of data entry. This gave engineers complete control over the system’s functions, enhancing both precision and creativity in performance and production.
The AMS DMX 15-80S was designed as a rack-mounted unit, 88.9mm high (2U) and 279.4mm deep, excluding knobs and connectors. The choice of high-quality components, alongside a motherboard system with plug-in circuit boards and ribbon cables, helped minimise maintenance issues, ensuring longevity and reliability in professional use.
When it was introduced, the AMS DMX 15-80S quickly became known for its compact size, rugged construction, and exceptional performance characteristics. Its versatility, coupled with its pioneering use of digital technology, made it one of the most valuable delay line systems available at the time, and it remains a significant milestone in the evolution of digital audio processing.
