Revox A77 Service Manual

6.3.1. Azimuth Adjustment, Playback Head, Coarse
( Max. Level 1
( Assembly and coarse adjustment after head exchange
per 4.1.2. )
Check of gap centering with respect to polished face :
— Mark polished face with grease pencil. Let tape run
short time. The gap must be in center of worn area.
— Set controls per fig. 6.3 — 53.
MON, ! OR
Fig. 6.3-53
tj
RECORD
MN
— Load 7.5" test tape and advance to azimuth adjustment
portion ( 10 kHz ).
— Connect AF-millivoltmeter to an OUTPUT terminal.
— Switch to PLAY and set output voltage to a maximum
with screw C ( fig. 6.3 — 54 ).
Fig. 6.3-54
6.3.2. Azimuth Adjustment, Playback Head, Fine
I Phase Method )
— Set controls per fig. 6.3-55.
RECORD
MEE
Fig. 6.3-55
— It is absolutely essential to accomplish the coarse adjust-
ment per 6.3.1. before using this method to avoid phase
errors larger than 90 °.
— Switch to PLAY and set output voltage to a maximum
( sharp ) with screw C.
— Secure screw C with a drop of lacquer.
6.3.3. Playback Level from Test Tape
— Set controls per fig. 6.3 — 56.
MONITOR
NA.
MAX
Fig. 6.3-56
CRAFAM, (MAN.. •
RE CORD
— AF-millivoltmeter remains connected to one output
( 3 V range 1.
— Advance test tape to level portion.
— Set playback mode switch to CH 1.
— Set output voltage 2 V with trimpot REPR LEVEL CH1
( fig. 6.3 — 57 ).
Ec il ... Er « RR 03CAL ', REA
3% 0
11011.1.2 CE11
o
3% n
RE REoeucE AYR, Cog •
Fig. 6.3-57
ole<0•0 UMW
ERIE,
[DMUS
-0
MITNE
CALM
o
U
— Set playback mode switch to CH 2.
— Set output voltage 2 V with trimpot REPR LEVEL CH 2.
6.3.4. Frequency Characteristic, Playback
( from Test Tape )
— Set controls per fig. 6.3.-58.
MONITOR
MAX
Fig. 6.3-58
RECORD
MIN
— Advance to frequency run portion of DIN or NAB test
band.
— AF-millivoltmeter, range 300 mV ( - 20 dB ).
Both channels can be measured simultaneously by chang-
ing back or forth between each frequency section I CH 1 /
CH 21.
27

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