AURORASOUND - HFSA-01

HFSA-01 is a hybrid pre-main amplifier utilizing the advantages of both vacuum tube and semiconductor. The tube EL84 delivers 14W + 14W power output. The model is equipped with bass and treble controls. The input stage has a built-in phono equalizer for MM-type cartridges, along with 3-channels of RCA unbalanced input terminals.
This model accepts speakers with 4Ωto 8Ω impedance. In addition, it has a headphone output.
The front panel is ornamented with Mahogany wood on both sides to enhance the retro appearance producing a rather relaxing atmosphere for more enjoyable audio life. HFSA-01 is designed with orthodox configuration, however, it fulfills the basic requirements such as sound quality and overall performance for a wide range source from high-resolution digital to analogue records that any generation and age demands.

The output vacuum tube EL84, a pentode equivalent to 6BQ5, is operated in push- pull configuration delivering extremely low distortion and
excellent frequency characteristics with ultra-linear connections. The driver for EL84 is a well-known Texas Instruments OPA604A, a high precision audio Op-Amp. Aurorasound developed a perfect phase inverter circuit with OPA604A to drive the push-pull operation in the most ideal way.

The tone-control section employs a CR-type for easy adjustments to achieve more rich bass and comfortable treble to meet listeners’ sound taste even with small-size speakers.   The phono equalizer uses Linear Technology’s semiconductor to achieve an excellent S/N characteristic with NF-type circuit configuration.
The power supply section is completely isolated between the vacuum tube and semiconductor to completely eliminating any interferences regardless of volume level and frequency range. The rectifier is of the super low noise Rohm’s silicon carbide diode.

The output transformer and power supply transformer are custom designed by Aurorasound, and manufactured by a Japanese company. This model employs carefully selected high-quality capacitors and resisters, as well.