While just by the weight we already know the Yamaha RX-V665’s power amp is not going to be that good, we are still surprised by what we found inside the cover.
First, the power transformer is unbelievably small for rated spec output. To make the matter worse, the capacitors in the power section are wimpy 6,800 µF ones. Just by the transformer and the capacitors alone we can concluded this receiver is not capable to drive high end speakers that typically are low ohm and inefficient.
But the worst and most shocking of all is this unit’s power amp is actually made of Sanyo STK series of hybrid power amp IC! Using hybrid IC for Hi-Fi equipment is already bad enough, using Sanyo? Yamaha does not even use its own power IC? Sanyo is really more suitable for boom box than midrange receivers. Luckily we only use this unit as pre-pro. If you are planning to use this unit to drive larger or low ohm speakers, you probably should pass this one.
If any cares, here is the link for Sanyo’s hybrid IC