不知道這邊有沒有用家，可不可以說說看法？
http://www.violectric.de/Pages/en/products/hpav200.php
HEADPHONES AMPLIFIER HPA V200
The HPA V200 was developped with the target to enable ultimate transmission quality for
low- , medium- and high-impedance headphones.
Einige Features:
* Electronically balanced inputs
* Unbalanced inputs with priority
* these are selectable as outputs
* USB 1.1 Input (48 kHz / 16 Bit)
* DC coupled amplifiers (switchable)
* PRE GAIN: Overall gain switchable in 5 steps
* Channel seperated circuitry
* NF trammission band exceeds 150 kHz (-3dB)
* High-grade volume control ALPS RK 27with optimized channel balance and lowest crosstalk
* Toroidal transformer, large smoothing capacitors
* Amplifier with 8 transitors per channel
* Outputs with relais controlled switch-on delay
The inputs and outputs are situated on the rear panel, they are equipped with
electronically balanced gold plated XLR connectors and unbalanced gold plated RCA connectors.
A USB input allows direct connection to a PC.
Volume control is provided with a high-grade ALPS RK 27 pot with a large full metal rotary knob.
Two headphones may be connected via 1/4" jacks on the front panel
Case and back panel are made of aluminium and are Nextel coated.
The 8 mm aluminium frontpanel is milled, sand blasted and black anodized. The labeling is laser engraved.
