The Sony DTC-1500ES was a high-end Sony ES Series Digital Audio Tape deck released around 1991, with a listed Japanese price of ¥300,000. Designed as a reference DAT machine, the Sony DTC-1500ES combined Sony’s digital recording technology, ES Series construction standards and an advanced transport system intended to make full use of the DAT format.
The Sony DTC-1500ES was a 2-channel stereo DAT deck supporting 48kHz 16-bit linear recording and playback, 44.1kHz 16-bit digital input recording and playback, 32kHz 16-bit digital input recording and playback, and 32kHz 12-bit non-linear recording and playback. This gave the Sony DTC-1500ES wide compatibility with the main DAT operating modes of the period, including digital recording from CD through SCMS-compatible one-generation copying.
One of the defining features of the Sony DTC-1500ES was its 4-head drum configuration. In addition to the conventional recording and playback heads, the Sony DTC-1500ES used two additional monitor heads, allowing simultaneous recording and tape monitoring in a similar operational style to a 3-head cassette deck. The front panel Rec Monitor switch allowed the user to change between source and tape sound during recording, making it possible to check the recorded signal while the recording was taking place.
The Sony DTC-1500ES used a 4DD motor mechanism, with dedicated direct drive motors for the capstan, supply reel, take-up reel and head drum. This approach simplified the mechanical layout and supported stable tape handling. The cassette compartment used an upright see-through design, allowing the tape running condition and cassette label area to be viewed through the front window.
For analogue to digital conversion, the Sony DTC-1500ES used a 1-bit A/D converter. This design shifted unwanted spectrum generated during A/D conversion far beyond the music signal band, allowing the low-pass filter to use gentler characteristics and reducing deterioration of phase and group delay characteristics. For digital to analogue conversion, the Sony DTC-1500ES used a 16fs 18-bit overlap staggered D/A converter system also used in commercial equipment. Two 8fs 18-bit D/A converters were used for each channel, with four D/A converters in total for left and right channel conversion.
The power supply of the Sony DTC-1500ES used separate transformers for the audio system, digital system and other circuits. The stabilised power supply circuit was built on an independent board, with symmetrical arrangement of positive and negative power supply components and wiring patterns to reduce circuit interference. Internally, the audio and digital circuit boards were separated by shield plates, while a copper-plated high-rigidity chassis was used to suppress magnetic distortion caused by eddy currents.
The Sony DTC-1500ES also used a 3mm thick aluminium top plate, a large copper plate for one-point audio grounding, and additional structural reinforcement through the surrounding frame and front-to-rear beams. These construction details placed the Sony DTC-1500ES firmly within Sony’s upper ES Series engineering approach, with the machine weighing 17.5kg.
The transport control system used a software servo. This allowed tape movement to be controlled through software settings, including slow movement at the beginning and end of search operations and high-speed movement up to approximately 200 times standard speed during travel. The system was designed to reduce tape stress, shorten sound generation time and improve cue and review operation.
The Sony DTC-1500ES used second-generation LSI technology for signal processing, integrating functions such as error correction, RAM control and digital input/output into a single LSI with an integration density of 20,000 gates. Mechanism and software servo control were also handled by a dedicated LSI, reducing the number of parts and simplifying the circuit board configuration.
The Sony DTC-1500ES included the DAT subcode functions that were central to the format’s editing and navigation system. Start ID could be written automatically at the beginning of a track or manually at a chosen position, and could be erased if required. Skip ID could be written at the beginning of a section to be skipped during playback, while End ID could mark the end of the required section of tape, causing playback to auto-rewind and fast forward to stop at that point.
A rehearsal function was provided for manual writing of Start ID, Skip ID and End ID points during playback, as well as A-B repeat point writing. During rehearsal, the selected point could be moved backwards or forwards in 0.3-second steps while listening, with the movement time shown on the display. Already written Start IDs could also be corrected during rehearsal.
The Sony DTC-1500ES allowed programme numbers to be assigned to Start IDs, enabling direct track selection through the numeric keypad during playback. Programme numbers were assigned automatically during recording and could also be used when writing Start IDs manually. A renumbering function allowed programme numbers to be renumbered from the start of the tape in one operation, while the Shift Number function could adjust Start ID placement in 0.3-second increments to provide a lead-in before the beginning of a track.
The Sony DTC-1500ES could record absolute time from the beginning of the tape, and also included a date function using a built-in clock. This allowed the year, month, day, day of week, hour, minute, second and AM/PM information to be recorded automatically into the subcode and recalled during playback.
Search and playback functions included absolute time search, AMS play, programme number search, music scan, repeat of a specified programme number, whole tape repeat and A-B repeat. Music scan could play sections from successive Start IDs for around 8 seconds each, with the playback time adjustable from 1 to 15 seconds. End search allowed the deck to locate an End ID or an unrecorded section of tape.
The Sony DTC-1500ES supported long play recording for up to 4 hours when using a DT-120 tape. Fade in and fade out were available for analogue input recording and for tape playback through digital output and line output. On the Sony DTC-1500ES, fade operation was also available during digital input recording. Fade in and fade out times could be set separately from 0.2 seconds to 15 seconds, and the function was linked with pause operation for editing and recording.
Connectivity included analogue line input and output, plus EIAJ-compliant coaxial and optical digital input and output. The optical and coaxial digital inputs could be selected from the front panel, and the optical input used a servo-type digital signal normaliser circuit to absorb cable jitter. The digital output could also be turned off when only line output was being used.
The Sony DTC-1500ES included two line outputs, fixed and variable, with the variable output level adjustable from the supplied wireless remote control. The supplied RM-D1500 remote could operate most of the deck’s functions and could also be used with a compatible Sony remote-controlled CD player for track selection and CD-synchronised recording.
The Sony DTC-1500ES was built as a full-size, heavyweight ES Series DAT recorder, with digital metering, peak margin display, subcode editing controls, numeric keypad operation, direct digital input and output, and the mechanical and circuit engineering expected of Sony’s higher-end digital audio components of the early 1990s.
Features
- 4-head drum configuration with recording, playback and monitor heads
- Simultaneous recording and tape monitoring
- 4DD motor mechanism with direct drive motors for capstan, supply reel, take-up reel and head drum
- 1-bit A/D converter
- 16fs 18-bit overlap staggered D/A converter system
- Two 8fs 18-bit D/A converters per channel
- Separate transformers for audio, digital and other circuits
- Copper-plated high-rigidity chassis
- 3mm thick aluminium top plate
- Software servo transport control
- Second-generation LSI signal processing
- SCMS-compatible digital copying
- Start ID, Skip ID and End ID subcode functions
- Rehearsal function with 0.3-second point adjustment
- Built-in date function for subcode recording
- Music scan, AMS play, repeat and A-B repeat
- Long play mode with up to 4 hours recording using DT-120 tape
- Fade in and fade out with adjustable fade time
- Coaxial and optical digital input and output
- Fixed and variable line outputs