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M17
DD Spec 6.105. DDHB 6.64. ACO. OBSOLESCENT.
M17/506
Balanced Line Sending Amplifier for office viewing and
similar
non-transmission
duties.
CH1/12A.
DD 1966.
WITHDRAWN .
AM7/507
Balanced Line Receiving Amplifier for balanced lines used
for office viewing and similar non-transmission duties.
CH1/ 12. DD 1967. WITHDRAWN .
AM7/508
Nat10ck Equalising Line Amplifier used to measure, amplify
and equalise as required the Nat10ck tone error signals
received at a slave site. Battery powered. Portable box.
DD 1968. WITHDRAWN.
AM8 LOUDSPEAKER AMPLIFIERS
M18/1
Part of LS3/1 Loudspeaker, O.B. Mains operated. Z in:
10kn. Z out: 2.5~-5~. Output: 15 watts into 25~ with
input of 0.5V. Commercial design. Now superseded by
AM8/4. DD 1957. ACO. OBSOLESCENT.
M18/2
Part of LS1/1.
r.m.s. input.
OBSOLESCENT.
Mains operated. Output: 3W with
Commercial design. DD 1958.
0.5V
ACO.
M18/2A
Part of Loudspeaker unit LS1/1. Mains operated amplifier
of commercial design. Improved to reduce r.f. pick-up.
Output: 3W with O.lV r.m.s. input. DD 1962. OBSOLESCENT.
M18/3
M18/4
Used on UN3/501. DD 1960. WITHDRAWN.
Part of LS5/1. Mains operated. Z in: high. Z out: 1~.
Output: 15W into 25~ with input of 0.15V. Commercial
design. Also used in place of M18/1 in LS3/1. Suffix A
denotes different equaliser for use in LS1/2. DD 1960.
ACO. OBSOLESCENT.
M18/5
Mains Operated Solid-state Amplifier designed for use with
small office loudspeakers. 178mm x 102mm x 57mm.
DD 1961. OBSOLESCENT.
M18/6
30W Valve Amplifier to operate a high grade 25~
loudspeaker system, e.g. suspended LS5/2. Input level:
-18dB. Z in: 18~. 387mm x 203mm x 22mm. Weight:
11.34kg.
DD 1963.
DD Spec 3.364.
DDHB 3.68.
ACO.
OBSOLESCENT.
AM8/6A
Similar to M18/6 but without equaliser, and output
arrangements modified to feed a ll0V-1ine Public Address
System. DD 1963. DD Spec 3.364. DDHB 3.68. OBSOLETE.
M18/8
Used to feed headphones and 3~ or l2~ loudspeakers in

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