Revox A77 Service Manual

Fig. 6.5-70
Type of Tape
AV - 3.75 ips
AV - 7.5 ips AV- 15 ' Ps
AGFA PE 31
4 dB
3 dB
REVOX PE 36 RX
REVOX 207
REVOX 601
AGFA PE 36
BASF PES 35 ( LH)
SCOTCH 202/203
5 dB 4 dB
2 dB
SCOTCH 150/215
5 dB 5 dB
Table 6.5-69
6.5.3. Azimuth Adjustment, Record Head, Fine
Set controls per fig. 6.5 — 70
....
Cr....
RECORD
The balance regulator must be set accurately ( per 6.3,
preparations ).
— Other conditions as up to now ( Record, Stereo, 10 kHz,
— 20 dB ).
— Set output voltage to a maximum ( sharp ) with screw B
( fig. 6.5 — 67 ) turn slowly - indication delay ! I.
— It is absolutely essential to accomplish the coarse adjust-
ment per 6.5.1. before using this method to avoid phase
errors larger than 90 °.
— Control possibility :
Pass through lower frequencies with sound generator.
Output voltage shall remain constant.
— Secure setscrew with a drop of lacquer.
6.5.4. Record level
— Set controls per fig. 6.5 — 71.
MONiTOR
Fig. 6.5-71
RECORD
— Playback level ( per 6.3.3. ) and balance adjustment ( per
6.3. preparations ) must be set.
— AF- generator to AUX - input ( connect in parallel ).
— AF-millivoltmeter to one OUTPUT terminal, range 300
mV.
— Load tape, switch to RECORD ( Steoeu ).
— Before- and- after- tape switch to INP. Supply 1000 Hz
from AF- generator, set generator level such that OUT-
PUT terminal voltage is 200 mV.
— Switch to NAB and adjust R EC LEVEL trimpots ( fig.
6.5-72 ) to obtain 200 mV at OUTPUT terminal, play-
back mode switch to CH 1 or CH 2 respectively.
o REM Mel
CM » MOM« MIIPMER Cél
o
MS MY
Fig. 6.5-72
SEC0110 AIM/ 011..1.0081 RECORD •••• 11'
C. C14 1
-0 e ‘O
!CLADS CM I
TRAP
6.5.5. Record Equalization
-0
-0
InCORD / JIRO
-0
ECILIALit
-o
•
CO rO n: , e0
— Switch AF- generator at same voltage (- 20 dB) to 12 kHz.
— Set controls per fig. 6.5 — 71 ( NAB ).
O
REM/
leEfflOWLE D•12
o ILA ilUes
Fig. 6.5-73
n,
Cél
000111...1.11
.%0
-0
"0
Ci• « CORO MM.. ,
rrr o "' 0
r e•
CD
0
▪ o
▪ 0
— Adjust output voltage from 0 to + 1 dB with trimpots
EQUALIZ. ( 0 dB = 200 mV / 1000 Hz per 6.5.4). Play-
back mode switch CH 1 both speeds, likewise CH 2 both
speeds.
6.5.6. Frequency Characteristic via Tape
— Set controls per fig. 6.5 — 71 ( NAB ).
— Calibrate AF-millivoltmeter I change slightly the signal
voltage till 0 dB or even- numbered indication is reached 1.
— Measure frequency characteristics 7.5 ips and 3.75 ips
I by changing playback function switch CH 1 / CH 2,
both channels can be measured, one after the other ).
6.6. Distortion Factor Measurements
VU- Meter Calibration
Noise Measurement
Erase Attenuation
Crosstalk Attenuation
6.6.1. Distortion Factor ( via Tape ), VU- Meter Calibration
— Set controls per fig. 6.6 — 74.
7
à
30

Revox A77 Specifications

General

Wow and Flutter	0.08% (7 1⁄2 ips)
Frequency Response	30Hz to 20kHz (7 1⁄2 ips)
Signal to Noise Ratio	60dB
Type	Reel-to-Reel Tape Deck
Track System	4-track, 2-channel stereo/monaural
Reel Size	Up to 10.5 inch reel
Motor	2 x reel, 1 x capstan
Inputs	Mic, Line
Outputs	Line
Tape Speed	3 3⁄4 and 7 1⁄2 ips