Operation Manual

5. Operation and performance

C SERIES Operation Manual rev 3.0.0

5.4.4. Ampliﬁer Input Gain

All C Series ampliers feature adjustable input gain. This versatility enables the amplier to accommodate a

multitude of system congurations with various input sources and speaker layouts.

Amplier gain is set globally for all four channels. The range is +23 dB to +44 dB in 3 dB steps. Individual channel

ne level adjustment is available using the potentiometers on the front panel.

The unique adjustable input gain feature of the C Series makes it easier to attain the optimum balance between

headroom and signal-to-noise ratio in the signal path. A weak signal at the input might require the gain to be raised

in order to achieve maximum output power with the lowest signal-to-noise ratio. A “hot” input signal, however,

would require a lowering of the gain to avoid sending the amplier into Voltage or Current clipping.

See Appendix to review the table containing Gain versus VPL setting implications for input sensitivity and output power.

NOTE: Bridge mode operation automatically compensates by -6 dB, keeping all channels at the

same gain.

5.4.4.1. Channel gain/level (front-panel pots)

Individual channel gain (level) may be adjusted using the potentiometers located on the front-panel behind the dust

lter cover. Range is from 0 dB to -innity in 21 steps. The attenuation is logarithmic, with the 12 o’clock position

indicating -10 dB.

Use your ngers or a screwdriver to adjust the potentiometers.

NOTE: If the level control is used to attenuate to a lower level than the headroom relative to input

sensitivity AND the amplier input is driven into clip, there is a danger of clipping the input stage before

the current or voltage peak limiters are activated.

5.4.4.2. Ampliﬁer sensitivity

Sensitivity is dened as how many volts (rms) or dBu (referred to 0.775 Vrms) are required to achieve full

(maximum) output power. As the output power varies with the load impedance, 4 ohms is usually the common

reference.

Since C Series ampliers are capable of providing multiple maximum output power levels through use of the

VPL feature, many sensitivity calculations may be required for a single amplier. We recommend use of the

DeviceControl software to simplify this process. DeviceControl’s Device View page, used in combination with the

DIP-switch settings display, will automatically produce a sensitivity calculation from the given data (VPL, Gain

and load).