A100 is a class A transistor headphone amplifier, which is carefully designed: The power comes from a high quality, custom made transformer with selected core material, then through a four-way regulating circuit, the voltage and current amplification stage are powered separately. This is to ensure the signal process is not interfered by power supply fluctuation.
The input signal is buffered by an AD827, to reduce the dependence of the signal source as well as the interconnection cable. The low impedance signal from buffer stage feeds into volume control, and then amplified by an OPA627BP (voltage amplification) and a class A transistor buffer constructed with BC557/567+MJE243/253 (current amplification). The output is separated in 2 ways, one for high impedance headphones (direct output) and the other one for low impedance headphones (in serial with 120Ohm resistor).
The designer has been working for years to research the acoustical performance from different circuits, working parameters as well as components. Combining extended listening test with the analysis from dScope Series III digital audio analyzer, A100 has achieved excellent performance – not only in test but also in listening.`
The highlights of A100:
Lightweight and durable aluminum housing design (Can match perfectly with D100)
Custom made, high quality toroidal transformer
Hand matched transistors with digital transistor tester
High end OPA627 OPAMP
Analogue UV level display
110-120V and 220-240V mains voltage (selectable in back plate)
Input signal impedance convert and buffer
Dual outputs to fit high and low impedance headphones.
Warning:Please adjust the volumn to the minimum before connecting the headphone to the A100 so as to avoid excessive volumn to damage your hearing!
680 ohm：75mw VPP：20V
300 ohm：170mw VPP：20V
50 ohm：343mw VPP：20V
33 ohm：1W VPP：17V