Coda Audio C25 - Manual (Page 6)

6 C25 User Guide Version 1.0
The latest version now also has improved signal level indication with 3 green LEDs in a ‘bar chart’
format. This gives a much clearer indication of level to the operator. The -3 dB and Limit LEDs
continue the bar format.
-3 dB Indicators
Part of the front panel signal level display, they will light up when the signal is approximately 3 dB
below the limiting point. The limiting point is set during production to be at the onset of clipping. The
response times of the -3 dB indicators (YELLOW) are faster than those of the limit indicators
(ORANGE).
PRC
This enables the user to set a maximum output power level below the rated output of the amplifier.
This reduction is controlled by switches on the rear panel, 2 per channel. Each channel has an LED
indicator (GREEN) active when either PRC switch is selected. A full table of PRC settings and the
resulting outputs are given in the Appendix. The possible settings are: -2dB, -4dB, -6dB. This relates
to the maximum output of the amplifier:
E.G.
C25 Max. power into 4 Ohm = 1250 W/+39 dBu
-2 dB PRC setting = 800 W/+37 dBu
-4 dB PRC setting = 525 W/+35 dBu
-6 dB PRC setting = 350 W/+33 dBu
In bridged mode the Channel A PRC circuit operates over both Channel A and B. In this mode
Channel B PRC is not used and is out of circuit.
Gain/Sensitivity Settings
Gain settings are changed internally by simple jumper links. Two rows of pins marked - GAIN A and
GAIN B - are situated on the input PCB (PCB701). A jumper link sets the gain and the settings are as
follows:
Link 1 & 2 gives 32dB gain
Link 3 & 4 gives 26dB gain
Link 2 & 3 gives approx. 33dB gain = 6dBu/1.5V sensitivity C25
Note:
Factory setting is normally link 1 & 2 = 32dB gain.
Setting higher gain does not change the maximum available power but changes the level of
signal input to achieve maximum power. In any case, provided that the input signal is less
than 20dBu/7.7V, the built in limiter circuit will prevent distortion within the amplifier.
The gain should be set to match the signal from the source, e.g. mixer, controller, equaliser
etc.
Introduction
The C25 are no compromise, high quality, class AB power amplifiers. There is no dynamic switching
of the audio or power rails, thus ensuring optimum sonic performance.
Fan speed is varied as required to keep the amplifier within its temperature limits. Signal limiters are
included to protect speakers from clipped signals.
The amplifiers include full DC and short circuit protection to ensure trouble-free service even in
‘harsher’ environments.