High current, Low negative feedback and wide bandwidth. ThIis was Stewart Hegeman design falosity from the time he designed the Citation II Amplifier. These falocities followed HK right through the hay day of Audio, which encluded the 680i (the i being the symbol for intensity or current).
This unit has been gone over completley by my Technician and runs as good as or better than when it was new. ANY FREIGHT CHARGE OVER $1.00 WILL REFUNDED!
Power amp circuit: DC Diamond Differential (same as the best vintage Sansui Products) The Unit Will work down to a 2 ohm load due to its high current and wide bandwidth. Plays louder the most 100 watt per channel receivers due to its high current capabilities.
Using the condition ratings from AuioGon I made this unit an 8 to be on the conservative side.
Thanx for looking
P.S. because the last few deals left no feedback you can check me out at gonna_love_it on E-Bay.