Very impressive (and dammed heavy) 2 channel stereo amplifier using 8 of 6550 or KT88s or KT120 or the preferred KT150. 
(KT88 shown) 
Awesome dynamics and authority, yet surprisingly musical. Suits the person who wants solid state for the low end authority, but is missing the richness and naturalness of live music. A great all rounder. Extremely easy to check bias using the onboard meter.

This is the power amp section of the Cyber 880i.  Paired with a Reference R 1.3 or a Reference 50, it is fabulous. 

 

CONTROL FUNCTIONS: Power On/Off 
POWER OUTPUT: 100 watt x 2, RMS 1kHz ( Ultra-linear ) 
TOTAL HARMONIC DISTORTION: less than 1%( 50watt, 1kHz ) 
FREQUENCY RESPONSE: ( -3dB points at 50 watt ) 6Hz-80kHz 
INPUT SENSITIVITY: 750mV 
INPUT IMPEDANCE: 100k ohms 
OUTPUT IMPEDANCE: 4, 8 ohms. ( User selectable ) 
SIGNAL ISE: 90dB 
CONSUMPTION: 300watt x 2 
INPUT INTERFACES: 1 group ( RCA )
OVERALL NEGATIVE FEEDBACK: Little 
VACUUM TUBE: 6550 or KT88 or  KT120 or KT150 x 8, 5687x 2, ECC82 x3 
WEIGHT: 35kg