A725 Professional Compact Disc Player
Studer A725 – The alternative! Professional quality for professional requirements
STUDER A725: ergonomic and uncomplicated operating with large-surface keys for the primary functions.
A725 – THE SENSIBLE SOLUTION TO THE CD DILEMMA
Sooner or later every radio station will have to consider the evaluation criteria for a CD player. Without doubt the question concerning the professionalism of its design will present itself.
Like with other audio equipment, judging the professionalism by the audio quality alone would not lead to meaningful results. The choice was limited to buying either CD players designed for hi-fi home use or very expensive CD systems.
This is how it was in the past. But now there is the STUDER A725. As you know it has been a long-standing tradition at Studer to offer truly professional solutions. And this solution is just as sensible as it is elegant: the A725 features uncompromising professional quality combined with the flexibility for upgrading to user-expandable systems.
THE PROFESSIONAL CONCEPT
The hi-fi version of the A725, the Revox B225 has already established itself as a CD player of the top premium category. It is rated as a professional unit and is used by broadcasting stations. The fully professional A725 therefore benefits from this situation, is reasonably priced,
and offers even more features for professional requirements. In addition the A725 is designed to function in a future computer-controlled multi-CD system – the corresponding interface as well as the following design characteristics are part of the future-safe concept:
- Short access times (average less than 1 second)
- Direct track and index selection
- Accurate and practical CUE facilities
- Balanced output stage with transformer and XLR sockets (optionally available in transformerless version)
- Fader start
- Extremely stable transport mechanism with die-cast aluminum alloy chassis
- Brushless CD motor with non-contacting servo control via Hall elements
- Short starting time (typical 0.3 s from PAUSE)
- High starting accuracy of ±1 frame (13.3 ms)
- Built-in digital level calibration generator
- Phase-linear oversampling principle
- Full mono compatibility by means of two separate D/A converters (essential for broadcasting applications)
- All printed circuit boards are of the plug-in type; no alignment necessary, offering simple maintenance
- Test CD and other accessories available for maintenance
ERGONOMICALLY OPTIMIZED OPERATING
The controls are ergonomically arranged for professional requirements. Large metal keys are available for the most frequently used CUE functions; with a STUDER CD player you can forget about miniature keys that you can't find in semidarkness!
The secondary function controls are grouped in the lower right field; the lower left field contains the controls for the comprehensive programming functions (since these functions are less frequently required in professional applications, this field can be completely covered with a metal shield).
PRACTICAL CUE FUNCTIONS
The A725 features special software for controlling the accurate CUE functions. The access times, start times, and starting accuracy satisfy professional requirements. Cueing and starting is performed with the minimum of key strokes.
MULTIFUNCTION LC DISPLAY
One of the outstanding features of the A725 is the logical implementation of its controls. Only two buttons need to be pressed for quickly and accurately retrieving the elapsed time per track or disc as well as the remaining time per track and disc. In addition a bar graph in dicates the approximate time in analog
The A725 operates according to the oversampling principle (176.4 kHz) and uses a combination of digital and analog filters for ultimate top audic
ith plug-in PCBs and microprocessor board specifically developed for the
REMOTE CONTROL SYSTEM WITH
All essential control commands can be transmitted through a serial remote control system (SERIAL LINK); functions and display data can be retrieved.
For testing the block error rate of discs, the A725 QC is equipped with a special
decoder PCB that features an output for checked.
Sockets for audio and control signals: balanced XLR, unbalanced CINCH fixed and variable level, as Highly rigid design of the A725 transport me chanism on die-cast aluminum allow chassis and
Technical data
AUDIO-DATA
| Number of channels: | 2 |
|---|---|
| Frequency response: |
20 Hz 20 kHz,
+0/-0.6 dB |
| Harmonic distortion: |
<0.006 %
(20 Hz 20 kHz) |
| S/N ratio, linear: |
>94 dB
(20 Hz 20 kHz) |
| S/N ratio, weighted: |
>100 dB (correspond-
ing to IEC 179, A curve) |
| Channel separation: | >90 dB (10 kHz) |
|
Output level:
- Audio Output fixed - Audio Output Variable - Audio Output Line |
2 V, R
i
< 500 ohms,
short-circuit proof 02 V, R i < 500 ohms, short-circuit proof +15 dBm, (at 0 dB, R i = 600 0hm), adjust- ing range 315 dBm, R i < 50 ohms |
| Phones output: | 4.5 V, Ri < 50 ohms, short-circuit proof |
| Channel balance (L/R): | < 0.2 dB |
| Phase linearity through digital | filtering (oversampling) |
| Mono compatibility through a | aparata D/A convertors |
OPTICAL SYSTEM
| Sampling frequency: | 44.1 kHz |
|---|---|
| Quantization: | 16 bit linear/channel |
| Pickup: |
AlGaAs semiconductor
laser |
| Wave length: | 0.78µm |
| Error correcting system: |
CIRC (Cross Interleave
Reed Solomon Code) |
| Preemphasis: |
50/15µs, selected
automatically by the subcode on the CD |
| DISK DRIVE / CONTROL | |
|---|---|
| CD-rotation speed: | 500 200 rpm |
| Scanning velocity: | 1.2 1.4 m/s |
| Wow and flutter: | quartz crystal precision |
| Maximum playing time: | 74 minutes |
| Starting precision: | ±1 Frame (13.3 ms) |
| Start delay from pause: | <0.6 s |
| Search time for any location: | <3s |
DISPLAY Multifunction LC display supplies the following status
| TRACK: |
the current position
can be determined either from the display- ed TRACK number or the 30-segment bar |
|
|---|---|---|
| INDEX: |
έν.
|
indices are displayed
automatically |
| TIME: |
9
101 |
either time can be read
out: TRACK ELAPSED TIME TRACK REMAINING TIME (up to track 37) DISK ELAPSED TIME DISK REMAINING TIME |
| PAUSE, AUTOSTOP, LOOP: | special operating modes are indicated | |
| PROGRAM MODE: |
each program step is
indicated with a reso- lution of one second |
|
| Ŝ | ||
| Number of program steps: | 19 | |
| Content of program steps: | TRACK, TIME or mixed | |
| Programming methods: | keyboard entry or setting of marks | |
| Step resolution: |
each step can be de-
fined with a resolution of one second |
|
| Special functions: |
special functions such
as LOOP, PAUSE, etc. can be programmed |
|
| GENERAL | ||
| Power requirement: |
100/120/140 V,
200/220/240 V ±10%, 50/60 Hz adjustable on voltage selector |
|
| Power fuses: |
100 140 V =
T 500 mA slow 200 240 V = T 250 mA slow |
|
| Power consumption: | 40 Watt max. | |
| Dimension |
450 x 109 x 332 mm
(w x h x d) |
|
| Weight: | 8.5 kg | |
SPECIAL VERSION
| trafoless | |
|---|---|
|
Adjusting range
AUDIO OUTPUT LINE: |
0 18 dBm |
| TI II I I | and the providence of the second |
A725 Professionel Compact Disc Player PCB line output trafoless
| Test CD frequency response | 10.241.023.0 |
| CD for adjusting the optical | 10.241.025. |
| system | 10.241.029.0 |
| Mirror for adjusting the optical | |
| system | 10.241.029.5 |
| Set of service PCBs and cables | 1.769.487.0 |
| Measuring filter for laser focus | 10.023.042.0 |
| Torx key No. 8 | 10.258.003.4 |
| Torx key No. 10 | 10.258.003.4 |
| Adhesion magnet for operat- | |
| ing the transport mechanism | |
| with opened drawer | 10 241 0300 |
483
.0330 (Ed. 0585) right by WILLI STUDER AG, CH - 8105 Regensdorf-Zürich
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