Q Series Operation Manual
15
The headroom available through the input stage to
the clip limiter is shown by the dotted lines as +10
dB at 141 Vpeak and +20.4 dB at 42 Vpeak. 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
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.
7.3. headroom, 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 adjusable
VPL and Gain circuitry affect input sensitivity and
output power:
The tables to the left of the drawing below, show
input sensitivity for
MA6.8Q
with an 8 ohm load and
141 Vpeak (max.) and 42 Vpeak (min.) respectively
for the eightdifferent gain stages b23 dB
and +44 dB. The resulting output power is displayed
in dBu, Vrms and Watt in the tables to the far right.
Complete input sensitivity tables for all VPL and
Gain settings for all
Q Series
models, can be found
at
www.martin-audio.com.
The headroom available through the input stage to
the clip limiter is shown by the dotted lines as +10
dB at 141 Vpeak and +20.4 dB at 42 Vpeak. These
lines illustrate the additional signal level that can be
accepted at the input before any significant distortion
will appear at the input stage.
Gain set to:
(DIP-switches)
+ 44 dB
+ 41 dB
+ 38 dB
+ 35 dB
+ 32 dB
+ 29 dB
+ 26 dB
+ 23 dB
Voltage Peak
Limiter set to:
(DIP-switches)
141 V
peak
118 V
peak
100 V
peak
85 V
peak
71 V
peak
59 V
peak
50 V
peak
42 V
peak
Input
sensitivity
dBu / V
rms
-2,0 / 0,6
1,0 / 0,9
4,0 / 1,2
7,0 / 1,7
10,0 / 2,5
13,0 / 3,5
16,0 / 4,9
19,0 / 6,9
Gain set to:
(DIP-switches)
+ 44 dB
+ 41 dB
+ 38 dB
+ 35 dB
+ 32 dB
+ 29 dB
+ 26 dB
+ 23 dB
Input
sensitivity
dBu / V
rms
-12,3 / 0,2
-9,3 / 0,3
-6,3 / 0,4
-3,3 / 0,5
-0,3 / 0,7
2,7 / 1,1
5,7 / 1,5
8,7 / 2,1
VPL set to 42 V
peak
VPL set to 141 V
peak
*) Headrom limited to +8dB at Gain set to +23 dB at Max. VPL
Complete tables for all VPL
settings can be found at:
www.martin-audio.com.
Hard/Soft switch
Gain select switches
Front panel
potentiometer
Dynamic
Gain reduction
VPL select switches
Class TD
Voltage Clip sensing
Current clip sensing
Monitoring Level
Temperature
Fault/Warning
Control Mute
Input Amplifier
Level control
Clip Limiter
Voltage Peak Limiter
Output Power Amplifier
Output
power
dBu / V
rms
42,2 / 100
40,7 / 84
39,2 / 71
37,8 / 60
36,2 / 50
34,7 / 42
33,1 / 35
31,8 / 30
Output
power
Watt
1200 W
880 W
630 W
440 W
310 W
220 W
160 W
110 W
+10 dB headroom to clip,
relative to input sensitivity *)
+20,4 dB headroom to clip,
relative to input sensitivity *)
OPERATION AND PERFORMANCE 7
All material © 2007. Martin Audio Ltd. Subject to change without notice.
