Cary Audio CAD 280sa V12i Power amp

Just received the amp. Looks so pretty. Hooked up to power and a preamp. All Tubes lit up, But hear nothing, double checked all wires are connected correctly. Anyone knows what could this be happened? At one point, got it work but very low sound with distortion, I am confused now, was it the bias issue ? I need help !! thanks

The amp has all 12 KT88, Russian tube.

Are all 12 of the LED's lit up? Is there a switch on the back for balanced and rca inputs and is it set to the correct one? Are the Standby and Power switch on the faceplate both in the correct positions?

No, all 12 LED not lit up when power on at the first time and after. Are they supposed light up during normal condition? input selector is set on RCA. power switch is set on position, standby switch is set on operate. I tried to adjust the right channel bias level slowly started from 0 counterclockwise to about half, noticed that all 6 kt88 were lit up for short while and hear low level distortion sound and then all LED is off. I turned off the unit, wait for while before turning back on, nothing happened. LED not lit up no matter how precisely turn the bias level. all 16 tubes lit up though. hope this will get you more understanding its current working condition. thanks for helping.

sorry, I meant turn clockwise.