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ABSOLARE Hybrid Stereo Amplifier User Manual 1.2
6. Operating the Unit
6.1. General Operation
Before turning on the Absolare Hybrid Stereo Amplifier, be sure that all tubes are
installed and all cables are connected securely.
After turning the Amplifier on, the power indicator LED on the front face plate will
start to blink. You will not hear any sound until the indicator LED stops blinking to
illuminate continuously which indicates all the capacitors are charged and internal
voltages are stabilized.
The Absolare Hybrid Stereo Amplifier will be ready to operate approx. 40 seconds
after turning on the power but attain full performance after 15 to 30 minutes.
There is a built-in thermal protection. If the output devices become too hot, output
power is reduced. It is heard as distorted sound.
Hence much of the voltage gain occurs in tube section, overall sound quality and
character is very dependent of the tube choice.
There is requirement for matching tubes to optimise performance. You can try
different types / brands of tubes in the left and right positions. The 12AU7 is a twin
triode tube, it is better to use tubes with closely matched internal triodes.
6.2. SEL Switch
Selects the active input connection, XLR or RCA connector. The unselected input is
terminated with a 620Ω resistor.
You may hear a loud pop noise when switching capacitor coupled tube sources due
to DC charge/discharge currents.
6.3. GAIN Switch
At
LOW
position, gain switch attenuates the sound level by -6dB. This compensates
for actual pro-level balanced sources. It can also be used to enable wider volume
adjustment range with highly sensitive speakers.
The gain setting affects both channels equally.
