Headroom, Sensitivity And Vpl/Gain Settings - Zenith 10K4 User Manual

7.3.2 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 +10dB 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 chart to the follow of the drawing below show
input sensitivity for a 10K4 with a 8Ω load and 150V
peak (max.) and 38V peak (min.) respectively for the
eight different gain stages between +23dB and
+44dB. The resulting output power is displayed in
dBu, Vrms and watts in the tables to the far right.
- The headroom available through the input stage to
the clip limiter is shown by the dotted lines as +10
dB at 150V peak and +16.1dB at 38V 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 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 +6dB to
the input sensitivity to achieve maximum output
voltage due to the automatic - 6dB gain
compensation inserted by the amplifier.
10K4 VPL and GAIN settings
Zenith 10K4 Amplifier Manual 16