Headroom, Sensitivity And Vpl / Gain Settings - Gisen Audio MM Series Operation Manual

6.3.2 H eadroom, sensitivity and VPL / Gain
settings
The input amplifier and limiter system is designed
to accommodate extremes of performance. Typically,
exceeding maximum input by much as +10 dB
will only result in a 1% increase in distortion. The
following schematics illustrate how the adjustable
VPL and Gain circuitry affect input sensitivity and
output power.
The tables to the left of the illustration 7.3.2 below
show input sensitivity for a FP 13000 with a 2 ohm
load and 195 V peak (max.) and 54 V peak (min.)
Respectively for the eight different gain stages
between +23 dB and +44 dB. The resulting output
power is displayed in dBu, Vrms and watts in the
tables to the far right.
Input Amplifier
Gain select switches
VPL set to 195 V
PEAK
Input
Gain set to:
sensitivity
(DIP-switches)
dBu / V
rms
1,0 / 0,87
+ 44 dB
4,0 / 1,23
+ 41 dB
7,0 / 1,7
+ 38 dB
10,0 / 2,5
+ 35 dB
13,0 / 3,5
+ 32 dB
16,0 / 4,9
+ 29 dB
19,0 / 6,9
+ 26 dB
22,0 / 9,8
+ 23 dB
VPL set to 54 V
PEAK
Input
Gain set to:
sensitivity
(DIP-switches)
dBu / V
rms
-10,1 / 0,24
+ 44 dB
-7,1 / 0,34
+ 41 dB
-4,1 / 0,5
+ 38 dB
-1,1 / 0,7
+ 35 dB
1,9 / 1,0
+ 32 dB
4,9 / 1,4
+ 29 dB
7,9 / 1,9
+ 26 dB
10,9, / 2,7
+ 23 dB
14 MM Series Operation Manual
Clip limiter
Level control
Front panel Dynamic
potentiometer Gain reduction
+ 10 dB headroom to clip
relative to input sensitivity *)
Complete tables for all
VPLsettings
+ 16,1 dB headroom to clip
relative to input sensitivity*)
*) Headrom limited to +5dB at Gain set to +23 dB at Max. VPL
Figure 6.3.2: MM13K VPL and GAIN settings
The headroom available through the input stage to
the clip limiter is shown by the dotted lines as +10
dB at 195 V peak and +16.1 dB at 54 V peak. These
lines illustrate the additional signal level that can be
accepted at the input before any significant distortion
will appear at the input stage.
If you use the level potentiometer in the
signal chain to reduce the level by an amount
greater than the headroom relative to input
NOTE
sensitivity, AND you drive the amplifier
to clip level, you are in danger of clipping the input
stage before the current or voltage peak limiters are
activated.
When bridging two channels, you must
add +6 dB to the input sensitivity to achieve
m a x i m u m o u t p u t v o l t a g e d u e t o t h e
NOTE
a u t o m a t i c - 6 d B g a i n c o m p e n s a t i o n
inserted by the amplifier.
Voltage Peak Limiter
VPL select switches
Hard/Soft switch
Voltage Clip sensing
Current clip sensing
Voltage Peak
Limiter set to:
(DIP-switches)
195 V
peak
170 V
peak
140 V
peak
116 V
peak
100 V
peak
80 V
peak
66 V
peak
54 V
peak
Output Power Amplifier
Class HTD
Control Mute
Monitoring Level
Temperature
Fault/Warning
Output
Output Power
power @ 2 Ohm
Watt
dBu / V
rms
6.500 W
45,0 / 138
6.500 W
43,8 / 120
4.970 W
42,1 / 99
3.540 W
40,5 / 82
2.550 W
39,2 / 71
1.850 W
37,3 / 57
1.330 W
35,6 / 47
960 W
33,9 / 38