REVOX A77
Is it quite useful to describe the REVOX A77? 25 years ago, each recording studio contained two or three of them; to make copies or to generate echoes or to delay the signal sent to the reverberations with plate or springs. Several accessories appeared progressively: plates and cores CCIR or NAB and a kit to use loops of magnetic tape
It left then a model 38 and 19 cm/s CCIR, generalized in the studios and, of course, most interesting, there is a model with 4 tracks stereo (1/4 of track) and a model Dolby B; to avoid both! For our use, model 19-38 is the only interesting one. It is necessary to point out that the Revox A77 is a "dual track" and not a true stereo machine (the difference is in the precise width of each track and the distance between these tracks). It is the same, and it’s there that difficulties can arise, for the head alignment which is a dual track and not single track; a small central band must thus not be unobtrusive and undesirable deaf noises can appear at the time a band already has been recorded or magnetized by a continuous-current field.
Lastly, do not miss the end of this page: if you are owner of an A77, you will find there, in pdf format, all the electronic diagrams necessary to its repair.
DESIGN FEATURES
General principle: |
|
mechanism with 3 motors, all electronically controlled |
|||
|
|
|
|
|
|
Tape speeds: |
|
19 cm/s |
(7 1/2 in/s) |
|
±0,2 % |
|
|
9,5 cm/s |
(3 3/4 in/s) |
|
|
|
|
|
|
||
|
|
|
|
|
|
Wow and Flutter: |
|
« ± 0,08 % @ 19 cm/s |
|
||
|
|
« ± 0, 1 % @ 9,5 cm/s |
|
||
|
|
|
|
|
|
Drift: |
|
<= 0,2% |
|
|
|
|
|
|
|
||
Diameter of the reels: |
|
maximum 26,5 cm ( 10 1/2 in ) |
|
||
|
|
|
|
||
Position of operation: |
|
Horizontal or vertical |
|
||
|
|
|
|||
Amplifiers: |
|
equipped entirely with transistors with silicon structure double diffusion |
|||
|
|
|
|
||
Response curve recording-reading: |
30 Hz @ 20 kHz +2/-3 dB |
|
à 19 cm/s |
||
|
|
50 Hz @ 15 kHz ± 1 , 5 dB |
|
||
|
|
|
|
||
|
|
30 Hz @ 16 kHz +2/-3 dB |
|
à 9,5 cm/s |
|
|
|
50 Hz @ 10 kHz ± 1,5 dB |
|
||
|
|
|
|
||
|
|
|
|
|
|
Harmonic distortion: |
|
<= 2 % @ 19 cm/s |
|
||
(maximum level @ 1 kHz) |
<= 3 % @ 9,5 cm/s |
|
|||
|
|
|
|||
Corrections: |
|
recording NAB, commutable reading NAB or IEC |
|||
|
|
|
|
||
Signal ratio/noise: |
|
>= 58 dB @ 19 cm/s |
|
||
(balanced with filter DC IF) |
>= 56 dB @ 9,5 cm/s |
|
|||
|
|
|
|
||
Retreat of cross talk (@ 1 kHz): |
>= 60 dB, mono |
|
|||
|
|
>= 45 dB, stereo |
|
||
|
|
|
|
||
Oscillation frequency: |
|
120 kHz, push-pull oscillator |
|
||
|
|
|
|||
Inputs per channel: |
cinch and jack |
Microphones commutable LO/HI LOW: 50 @ 600 ohms 0,15 mV |
|||
|
|
HIGH: 100 kohms 2,5 mV |
|
||
|
|
RADIO: 33 kohms 2,5 mV |
|
||
|
DIN 5 poles cinch |
AUX: 1 Mohms 35 mV |
|
||
|
|
|
|
||
Outputs per channel: |
DIN 5 poles cinch |
OUTPUT max. 2,5 V / Ri 600 ohms |
|
||
|
jack |
RADIO max. 1,2 V / Ri 2,5 kohms |
|
||
|
|
PHONES ear-phones 200 to 600 ohms |
|
||
|
|
|
|||
remote Control: |
|
all remotely controllable functions by impulses |
|||
|
|
|
|||
Amplifiers of loudspeakers: |
plug-in, delivered on request |
|
|||
|
|
|
|
||
Power of exit: |
|
musical power20 W ( 10 W per channel ) |
|
||
(load 8 ohms distortion <= 1 %) |
in sinusoidal mode16 W ( 8 W per channel) |
|
|||
|
|
|
|
||
Output impedance: |
|
4 to 16 ohms |
|
||
|
|
|
|
|
|
Built-in loudspeakers (model bag): |
2 loudspeakers per channel (disconnected automatically at the time of the |
|
connection of external loudspeakers) |
|
|
Component: |
54 transistors, 32 diodes, 4 rectifiers with silicon, 1 photo resistor, 4 |
(with the amplifiers of loudspeakers) |
relays |
|
|
Power supply: |
stabilized |
|
|
Tensions of the network: |
110, 130, 150, 220, 240, 250 V-, 50 and 60 Hz |
|
|
Consumption: |
70 W without the amplifiers of loudspeakers between 70 and 100 W with |
|
the amplifiers |
|
|
Fuses: |
0,5 A for 220 to 250 V 1,O A for 110 to 150 V |
|
|
Weight: |
Approximately 15 kg |
|
|
Loading...