Advent 100 nru sm

Page 1

SERVICE MANUAL

59va

cum"

In FLU

ADVENT MODEL 100

NOISE REDUCTION UNIT

Advent Corporation
377 Putnam Avenue
Cambridge, Mass. 02139

NRU 10-70

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PERFORMANCE AND ELECTRICAL SPECIFICATIONS
FREQUENCY RESPONSE:

Dolby Out: 20-20,000Hz +0 -ldb

Dolby In: 20-20,000Hz +l -2db

With MX FILTER "in" the upper limit is 15 kHz
DISTORTION:

Less than 0.5% THD @ Dolby Level, 20-20,000Hz
SIGNAL T0 NOISE RATIO:

(Measured straight through exclusive of tape deck)
-66db from Dolby Level

NOISE REDUCTION vs. FREQUENCY:

3db @ 600Hz
Sdb @ 1200HZ
9db @ ZHOOHZ
lOdb @ 4000Hz to 20,000Hz

INPUT SENSITIVITIES:

MIC: 0.5mv for Dolby Level @ 1000 ohms (50,000 ohms
after serial number 02800)

LINE: 60mv for Dolby Level @ 50,000 ohms
FROM TAPE RECORDER OUTPUT: lSOmv for Dolby Level @

50,000 ohms. (Adjustable
by PLAY CAL control)

OUTPUT LEVELS:

T0 TAPE RECORDER INPUT: Maximum 500mv for O VU
tape level @ 1000 ohms.

TO AMP INPUT: 1.0 V from O VU tape level,less than
1000 ohms output impedance.

MX FILTER:

less than ldb down @ lSkHz
greater than 30db down @ 19kHz
greater than 20 db down @ 38kHz

In open reel recording, Dolby Level is the same flux level
on the tape as Ampex Operating Level.

For cassettes, Dolby Level is defined as a flux level on
the tape of 200 nanoWebers per meter.