Tannoy I9 - Manual (Page 7)

5.1 Connectors and Cabling for Distributed Line Operation
Connections are identical to those used in low impedance mode, via the4-pole Neutrik
Speakon
 connectors (see section 4.1):
Pin 1+ is Positive
Pin 1- is Negative
Distributed line systems are much more efficient in power transfer and do not require as
large cables as in low impedance mode. This can create significant savings in cable
costs. Refer to the following table for guidance in cable length versus power loss. A
power loss of 11% amounts to a loss of 0.5db, and 50% to a loss of 3dB.
CABLE
RUN (m)
C.S.A. OF
EACH
CONDUCTO
R (mm)
AWG CABLE
RESISTAN
CE Ω
% POWER
LOSS
INTO
70V 60W
100V N/C
% POWER
LOSS
INTO
70V 30W
100V 60W
% POWER
LOSS
INTO
70V 15W
100V 30W
% POWER
LOSS
INTO
70V 7.5W
100V 15W
100 1
1.5
2.5
17
15
13 3.3
2.1
1.3 4.8
3.1
2.0 2.4
1.5
1.0 1.2
0.8
0.5 0.6
0.4
0.2
500 1
1.5
2.5
17
15
13 16.6
10.4
6.6
20.3
13.7
9.1
11.1
7.2
4.7
5.9
3.8
2.4 3.0
1.9
1.2
1000 1
1.5
2.5
17
15
13 33.2
20.8
13.1 33.7
24.1
16.7 19.9
13.5
9.0
11.1
7.2
4.7
5.9
3.8
2.4
5000 1
1.5
2.5
17
15
13 166
104
65.7
71.8
61.4
50.1 55.5
43.8
33.0 38.4
28.1
19.8 23.7
16.3
11.0
Distributed line operation is a good choice when so many speakers are used that the
impedance would be too low to run from a low impedance amplifier
For distributed line (70.7/100V) operation, the rotary switch can be adjusted to select
the wattage required. The table below shows the rotary positions (moving clockwise) for
70.7 and 100V operation.
Position
(Clockwise)
70.7V line
Watts
100V line
Watts
A 7.5 15
B 15 30
C 30 60
D 60 N/C
Figure 5b demonstrated the method of connecting the speakers to a distributed line
amplifier.
Figure 5b
7