Audio GD Roc

Roc is a balanced Class A headphone amplifier and that also serves as a preamp.  It is high powered and has served me well on HD650, fostex T50rp and HifiMan 400. Selling to tryout a tube amp. This is from a smoke free home. I purchased on Head-fi. There are a couple minor scratches on top. Original price was $730. 
From the product website: Output level: 20V RMS (Max ) Output power: 25 ohm: 750MW 62 ohm: 1800MW
100 ohm: 2500MW
300 ohm: 1350MW
600 ohm: 700MW

What is Roc: 
1, Roc is base on Phoenix's design, it is a true balanced design, signal circuits and chassis box style the same as Phoenix.
2, Roc applies 4 floors ALPS volume pots, and applies class A PSU.
3, Roc has gain balance control between RCA and XLR, so between RCA input and XLR input, there is the same output level . 
　
Characteristics:   -A true fully balanced headphone amp with preamp function. 
 -Adopting the Current Audio Signal Transmission (ACSS) technology in audio circuits, so Roc sounds as "a wire with gain".
 -Power supply is a class A parallel voltage regulator design. 
 -The 4 floors ALPS volume pots can continuously adjust volume level.