XiangSheng 728A BK Vacuum Tube Pre-Amplifier Preamp Shigeru Wada Japan circuit U

Product Description: 
The pre-amplifier improved based on famous Wada Shigeho's Style Electric circuit,which was 
Introduced by Wada Shigeho in the early 1960s and gave an excellent performance. 
Regarding the Wada Shigeho's Style Electric circuit, it not only still keep the good 
features of Marantz7, meanwhile it have superrior features in Dynamic, High/lLow Frequency 
Response, Resolution and Signal to Noise Ratio as compared to Marantz7. But apart from 
above features, it’s also not inferior to Marantz7 in Sound stage and airy feeling. 
Adopt 4pcs paper in oil capacitors and German WIMA capacitors for coupling effect, make the 
sound warm and delicate. 

Parameter: 
Input Impedance：100K 
Output Impedance：600 ohm 
Total Hamonic Distortion： less than 0.01% 
Frequeney Responses： 10Hz-30KHz 
Signal to Noise Ratio： 90dB 
Input Jack： 4 groups 
Output Jack：2 groups 
Supply Votage： AC100V-AC240V available 60Hz/50Hz 
Size: 430mm(Width )×90mm(Height )×290mm(Depth ) 
Vacuum tubes: 12AT7×2、12AU7×2、6Z4×2 
Working environment: Temperature:5℃―40℃ 
Humidity：35%―80% 
Weight：about 8.5 Kg 
Gross weight: 10kg

WITHOUT key to Adjust bass and treble Version: