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AM9
Gain: Pre-set 10dB to 40dB. Output: +12dB maximum into
1200~. PCB 57mm x 41mm. Superseded by AM5/7. DD 1966.
DD Spec 3.438. DDHB 3.141. ACO. OBSOLESCENT.
AM9/9
Used in Type D studio equipment. Comprises two separate
amplifiers on a printed board forming one microphone
channel input stage. Gain of each is controllable from
4dB to 30dB by an external variable resistor. Output:
+14dB
maximum
into
1200~.
First
used
PA8/260A.
Superseded by AM9/10. DD 1966. DD Spec 3.439. ACO.
OBSOLESCENT.
AM9/11
Twin Microphone Amplifier used in Type D sound desks for
two similar microphone channels each with gain variable
from 4dB to 70dB in 3dB steps, and with bass cut and
whistle filters. Includes 2 AM9/10, 2 UNl1/6C. First
used BH Continuity. CH1/37A. DD 1969. DD Spec 3.511.
ACO. OBSOLESCENT.
AM9/l3
Microphone Amplifier and Tone-source used in CD2M/508.
Input signals at levels from -84dB to -44dB are amplified
to give an output level of -30dB, and the gain is variable
in
five
-8dB
steps
by
means of a manual control.
An
electrically separated 1kHz test oscillator with a -30dB
output level is included. PCB with 33 way ISEP connector.
Indexing positions 1, 25, 29. RD 1972. ACO.
OBSOLESCENT.
AMlO HEADPHONE AMPLIFIERS
(Sub Group previously defined as "Monitoring Amplifiers" DD 1977)
AMlO/1
Small battery operated transistor amplifier for use with
headphones. Variable gain of 35dB maximum with high
impedance load. 12lmm x 95mm x 57mm. Transistors: 2
OC71. DD 1961. DD Spec 3.310. OBSOLETE.
AMlO/2
Amplifier, Monitoring, L.S. used on EP6/50l.
circuit board. DD 1964. OBSOLESCENT.
Printed
AMlO/3
Amplifier, Monitoring, Bias Eraser, used on EP6/50l.
Printed circuit board. DD 1964. OBSOLESCENT.
AMlO/4
Used in MN4/l. Printed
DD Spec 5.98. OBSOLESCENT.
circuit board.
DD 1965.
AMlO/5
Headphone Monitoring Amplifier for feeding low or high
impedance headphones. Input: -l5dB. Output: 1W into 4~,
+20dB into 5k~. Powered from 50V station battery. Box
l27mm x 121mm x 57mm. DD 1970. DD Spec 3.524(70).
DDHB 3.136(73). OBSOLESCENT.
AMlO/6
Headphone Monitoring Amplifier, used in RP2/8.
Two

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