November 2006
Flying Mole
CAS10 Integrated Amplifier: Measurements
All amplifier measurements are performed
independently by BHK Labs. Please click to learn
more about how we test amplifiers there. All measurement data, including graphical
information displayed below, is the property of SoundStage! and Schneider
Publishing Inc. Reproduction in any format is not permitted.
 Measurements were made at 120V AC line voltage with both
channels being driven; measurements made on left channel unless otherwise noted; an Audio
Precision AUX0025 lowpass filter was used unless otherwise noted.
 This integrated amplifier does not invert polarity.
 AC line current draw at idle: 0.26A
 Input sensitivity for 1W output into 8 ohms, volume at
maximum, Lch/Rch:
14.1mV/14.8mV
 Input impedance @ 1kHz: 9.85k ohms
 Output impedance at 50Hz: 0.09 ohms
 Gain, output voltage divided by input voltage, volume at
maximum, Lch/Rch:
200.2X, 46.0dB/190.6X, 45.6dB
 Output noise, 8ohm load, 1kohm input termination, Lch/Rch
 Volume control at reference position
 wideband without AUX0025 filter: 197.4 mV, 23.1dBW /
224.4mV, 22.0 dBW
 wideband: 1.97mV, 63.1dBW / 2.23mV, 62.1dBW
 A weighted: 0.30mV, 79.5dBW / 0.26mV, 80.7dBW
 Volume control at maximum
 wideband: 49.7mV, 35.1dBW / 7.0mV, 52.1 dBW
 A weighted: 2.4mV, 61.4dBW / 1.5mV, 65.5dBW
 Volume control at minimum
 wideband: 1.9mV, 63.4dBW / 2.2mV, 62.2 dBW
 A weighted: 0.25mV, 81.1dBW / 0.24mV, 81.4dBW
Power output with 1kHz test signal
 8ohm load at 1% THD: 90W
 8ohm load at 10% THD: 113.1W
 4ohm load at 1% THD: 135.3W
 4ohm load at 10% THD: 173.3W
General
The Flying Mole CAS10 is a mediumpower solidstate
integrated amplifier using their proprietary switchingamp technology. Overall gain of
this unit is on the high side for an integrated amplifier of the type so popular these
days – the kind with a passive selector switch and volume control preceding a power
amplifier. The CAS10 has a active linelevel preamp stage within, and with this in mind,
the overall gain is appropriate for this topology.
Chart 1 shows the frequency response of the amp with
varying loads. This data was taken without the Audio Precision AUX0025 low pass filter to
show the true frequency response of the unit. As is typical of most switchingamp designs,
the highfrequency response is a strong function of load impedance. Output impedance as
judged by the closeness of spacing between the curves of opencircuit, 8ohm, and 4ohm
loading, is reasonably low below about 1kHz. The impedance variations of the NHT
dummyspeaker load start to show above about 1kHz as the output impedance rises with
increasing frequency. Still, the variation with the NHT load is a reasonable +/0.5 dB
over the audio range. The frequency response was quite independent of volume control
setting with volume control tracking within 0.5dB or less from full volume down to 60dB.
Chart 2 illustrates how total harmonic distortion plus
noise vs. power varies for 1kHz and SMPTE IM test signals and amplifier output load.
Amount of distortion is reasonably low and power into the 4ohm load is, as typical,
higher than for the 8ohm load.
Total harmonic distortion plus noise as a function of
frequency at several different power levels is plotted in Chart 3. Amount of rise in
distortion at high frequencies is moderately low.
Damping factor vs. frequency is shown in Chart 4 and is of
a value and nature typical of many solidstate amplifiers, being high up to several
hundred Hz and then rolling off with frequency.
A spectrum of the harmonic distortion and noise residue of
a 10W 1kHz test signal is plotted in Chart 5. The magnitudes of the ACline harmonics are
low and simple, and intermodulation components of ACline harmonics with signal harmonics
are also low. Signal harmonics consist of a dominant second, a continuous spectra of
higher components, and a rising noise floor starting at about 7kHz.
Chart 1
 Frequency Response of Output Voltage as a Function of Output Loading 
Red line: open circuit
Magenta line: 8ohm load
Blue line: 4ohm load
Cyan line: NHT dummyspeaker load
Chart 2  Distortion as a Function
of Power Output and Output Loading 
(line up at 10W to determine lines)
Top line: 4ohm SMPTE IM
Second line: 8ohm SMPTE IM
Third line: 4ohm THD+N
Bottom line: 8ohm THD+N
Chart 3  Distortion
as a Function of Power Output and Frequency 
8ohm output loading
Cyan line: 80W
Blue line: 30W
Magenta line: 10W
Red line: 1W
Chart 4  Damping Factor
as a Function of Frequency 
Damping factor = output impedance divided into 8
Chart 5  Distortion and
Noise Spectrum 
1kHz signal at 10W into an 8ohm load
