1： Introduction:
 

      9i-906 "silver fox" is a headphone power amplifier with high performance,  strong power supply and high current output.  It's circuit design is complex and perfect ,  4 pairs of  high-power British FET are used in output part , the output power is 30Ω/20W.   Ultra low sensitivity  headphones can also be driven with excellent audio performance.

     Since its launch, the Silver Fox has received widespread acclaim. Both in the United States and in Europe, numerous users have given it high marks. Some well-known hifi websites have also made detailed reviews, such as, 

https://www.head-fi.org/showcase/cen-grand-9i-906-silver-fox.26606/

https://6moons.com/audioreview_articles/cen-grand-silverfox/

https://www.head-fi.org/threads/cen-grand-9i-906-silver-fox.966805/     （Long Thread）

https://www.hifistatement.net/tests/item/3510-cen-grand-9i-906-silver-fox

      9i-906 "Silver Fox" has four output modes: Normal, Balanced(BTL), Virtual Ground(Active G) and Parallel, as well as three low resistance modes and one high resistance mode. A variety of headphones can be matched .

      Two  balanced and two unbalanced inputs were installed on the unit back panel.  Even if an unbalanced signal is input the internal circuit will convert it into balanced signal .  Therefore, you will also get the maximum output power even if you input an unbalanced signal .

       For the best sound quality, a balanced input is highly recommended unless you only  have unbalance signal. 

     "Silver fox" has four output interfaces: 4 pin XLR balanced, 6.35 single , 4.4 balanced as well as double 3 pin XLR balanced .

2： Operating instructions:
 
     "Silver fox" is a pure headphone Amp and the operation is very simple.   There are only several function keys:  power switch, input selection, output mode selection ,  high/low resistance selection.
 

      Long press the out key to switch between high and low resistance modes.  There are four kinds of headphone impedance options for choice :  high resistance, low resistance 1, 2 , 3.  You can selected any mode according to the characteristics of the headphonet as well as sound quailty you hear . High resistance mode is recommended in most cases.

     If you use ultra-high sensitivity headphones such as earbuds, you may hear a slight noise. Don't worry, Silver Fox has 3 low gain modes for you to choose from. You can choose one of the low resistance 1-3 modes and the noise will be eliminated.

3： Performance parameters:

 
Power: 20W (30 Ω BTL, distortion 0.02%)

Frequency response : 20-20KHz (0.2db)

Dimensions : 430mm X 100mm X 360mm

Net Weight : 12kg

GRoss Weight : 13.7kg