Yet another one of my 2013 fall finds—and strangely familiar! I used to own a Harman Kardon 430 which was my prized posession for quite a long time, and just like the 430, this unit has the same twin powered design that these HK receivers are known for. I also need to get into the habit of taking more photos of these units, because some people like to see the guts. So here it is:
This model is a little strange, though. I can't really describe it other than it feels a little cheaper, considering the build quality alone. I only have my previous 430 for comparison, but both the knobs and the tuner dial feel a bit cheap. I did some digging, and from what I could find, other owners seem to have the same opinion. I don't think it's low quality but any means, I just feel like maybe it's an earlier model that got refined with later versions. There is also very little information to be found online—I downloaded the service and owner manuals, but neither of them list the specifications. It appears as though it's related to the HK 930, as it shares the same tuner dial design and knobs. My old 430 seems to be more closely related to the 730 for the same reasons. I am starting to think that maybe the 630/930 were early models, and the 430/730 were their successors.
That said, I didn't need to do much for this piece other than give it a good polish and replace the feet. All of the bulbs were working and there was no need to make any other internal adjustments. One interesting feature it has, is dual-channel bass and treble knobs. If you want, you can individually adjust the tone for each channel. This feature sounded strange to me at first, but I realized its actually extremely handy in certain situations. If you have a speaker stuffed in the corner of a room and it has a rear bass port (like me*), that speaker might have a significantly higher bass output as a result. So with this receiver, you can simply adjust one of the knobs to compensate.
*I actually had to laugh at myself after writing this. I realized it's ambiguous whether I mean that I have a speaker stuffed in the corner of a room, or whether I literally have a rear bass port (if you know what I mean). You decide.