Released in 1979, the Eumig FL-1000µP was an advanced three-head cassette deck designed around microprocessor control, opto-electronic capstan regulation, extensive tape calibration facilities and direct computer interfacing. Available in matte black or brushed aluminium finishes, it combined a front-loading transport with professional-style mixing controls, a digital tape-location system and support for ferric, chromium dioxide and metal-alloy cassette formulations.
The Eumig FL-1000µP used separate record, playback and erase heads, allowing the recorded signal to be monitored directly from the tape while recording remained in progress. This arrangement enabled immediate comparison between the incoming source and the signal being reproduced from the tape. A double Dolby noise-reduction system ensured that the monitored playback signal was correctly decoded during recording.
Tape motion was regulated by Eumig’s opto-electronic capstan servo-control system. Instead of relying on a conventional heavy flywheel, the transport used a lightweight disc incorporating 2,500 precisely spaced, photo-etched radii. As the capstan rotated, the system generated 15,000 pulses per second. These pulses were compared with a fixed reference so that corrective signals could be applied within microseconds. The resulting specified wow and flutter figure was 0.035% WRMS.
A separate motor simplified the reel-drive system and provided the controlled mechanical power required to operate the tape gate, capstan and braking mechanisms. This avoided the shocks and potentially inconsistent operation associated with conventional solenoids, while also helping protect the head alignment. The Eumig FL-1000µP included the Computest system for optimising recording performance to suit individual cassette formulations. Ferric, chromium dioxide and metal-alloy tapes could first be selected through the three-position bias and equalisation control. More precise adjustment could then be performed for differences in tape sensitivity and optimum bias between individual brands.
When Computest was engaged, the normal inputs were bypassed and the letter “t” appeared on the digital display. A 400Hz test tone was used to adjust tape sensitivity to the correct Dolby level, while a combined 400Hz and 14kHz signal allowed the bias to be adjusted for an even response across the audio spectrum. A Balance Scope formed by two LEDs flashed equally and alternately when the correct setting was reached. When testing was completed, the cassette automatically rewound to the exact starting position so that the test tones would be erased when normal recording began.
The Eumig FL-1000µP provided two stereo mixing inputs. One could be used for a line-level source, while the second could accept either another line source or microphones. The second microphone input could also be configured for near or distant microphone placement through its two sensitivity positions. A three-position reverb control allowed adjustable reverberation from either input to be added to the other. Separate input controls were accompanied by an independent master recording-level control. A cross-fader provided smooth transitions between the two input sources and could also be used when balancing instruments or other programme sources.
Recording levels on the Eumig FL-1000µP were displayed through a fluorescent peak-reading meter containing 42 segments per channel. Unlike an average-responding mechanical meter, the electronic display was designed to show brief programme peaks that could otherwise cause tape saturation and distortion. In source-monitoring mode, the display included the effects of the recording pre-emphasis, allowing the user to see the level actually being applied to the tape.
The level display on the Eumig FL-1000µP included a peak-hold function that retained the highest reading while continuing to show lower-level variations. A 6dB attenuator accommodated higher-output metal tapes, while a two-position dimmer adjusted the brightness of the fluorescent display. A switchable limiter was also included. Its fast attack and slow release characteristics were intended to control excessive peaks without preventing its use for music recording. An LED illuminated only when the signal exceeded the limiter threshold.
Transport operation was controlled by an integrated microprocessor. The fast-wind, play, stop, pause and record touch controls could be pressed in any sequence, with transistor logic protecting the tape and mechanism. Automatic rewind could be directed to the zero position or to another selected location, with stop and repeat options available. The electronic counter formed part of the microprocessor control system rather than using a conventional mechanical counter. This avoided the imprecision associated with belt slippage and also contributed to the deck’s tape-location functions. The same numbered touch controls used for the transport could perform a second role similar to calculator keys.
By pressing the go-to and memory controls together and entering a counter value, the Eumig FL-1000µP could automatically advance or rewind to the chosen position. The transport slowed as it approached the location and corrected any small overshoot. The display showed “End” when the end of a cassette side was reached and displayed “t” while the Computest calibration mode was operating. A major feature of the Eumig FL-1000µP was its ability to communicate directly with many contemporary 8-bit microcomputers. Its computer interface used an eight-bit parallel bus compatible through suitable connections or adaptors with systems including the Commodore PET, Apple II and Radio Shack computers.
Each deck incorporated a user-programmable diode matrix that could assign an individual address to as many as 16 Eumig FL-1000µP decks. The internal MOS-TEK MK3870 LSI microprocessor provided storage and control capabilities that allowed groups of machines to operate individually, simultaneously or sequentially. A programme could, for example, instruct one deck to locate a particular counter position and record the output from another machine. The multi-machine software allowed control over recording, playback, stop, rewind, fast-forward, counter loading, memory loading, go-to functions and other transport operations. This made the system suitable for automated broadcasting, commercial playback installations and discotheques as well as domestic computer-controlled audio systems.
The index programme allowed the deck to record digital index information onto the opening section of a cassette side between counter positions 0031 and 0051. Up to 15 selection titles and locations could be stored for each cassette side. Once the cassette was inserted, its contents could be displayed on a computer monitor and selected tracks could be played in any programmed order. A rewind instruction could also be included at the end of the chosen sequence. Because the computer interface was not restricted to a single dedicated task, users could develop their own software routines or use Eumig’s programmes. This allowed the FL-1000µP to function as both a high-performance cassette recorder and a programmable component within a larger automated audio installation.
The deck provided fixed and variable outputs to simplify level matching with other components and to permit adjustable headphone listening. The headphone output was designed for impedances from 8 to 2,000 ohms and used a 6.35mm stereo socket. A switchable multiplex filter prevented the 19kHz pilot signal in stereo FM broadcasts from interfering with the Dolby encoding process. The Eumig FL-1000µP was constructed to standard 19-inch rack dimensions and could therefore be installed in professional or domestic equipment systems. It was offered in matte black or brushed aluminium and was designed to accompany Eumig’s M-1000 DC power amplifier, T-1000 digital synthesis FM tuner and C-1000 DC preamplifier.
Features
- Three-head record, playback and erase configuration
- Direct off-tape monitoring while recording
- Microprocessor-controlled front-loading transport
- Opto-electronic capstan servo-control system
- 15,000 capstan control pulses generated per second
- Computest tape sensitivity and bias calibration
- Support for ferric, chromium dioxide and metal-alloy tapes
- 400Hz Dolby-level calibration tone
- Combined 400Hz and 14kHz bias-adjustment signal
- LED Balance Scope calibration indicator
- Automatic return to the start of the calibration section
- Two stereo mixing inputs
- Selectable line-level or microphone operation for the second input
- Near and distant microphone sensitivity settings
- Adjustable cross-fader
- Independent master recording-level control
- Three-position reverb routing
- 42-segment fluorescent peak-level display for each channel
- Peak-hold display function
- 6dB display attenuator for high-output tapes
- Two-position display dimmer
- Switchable limiter with LED activity indication
- Double Dolby noise-reduction system
- Switchable FM multiplex filter
- Electronic four-digit tape counter
- Programmable go-to tape-location function
- Automatic rewind, stop and repeat functions
- End-of-tape indication on the digital display
- Eight-bit parallel computer interface
- Compatibility with suitable Commodore PET, Apple II and Radio Shack computer interfaces
- User-programmable machine addressing
- Control of as many as 16 decks through suitable software
- Computer-controlled recording, playback, stop, rewind and fast-forward functions
- Computer loading of counter and memory positions
- Digital cassette indexing for up to 15 selections per side
- Fixed and variable outputs
- Standard 19-inch rack dimensions
- Available in matte black or brushed aluminium