Built in an era when someone thought it would sell better if if looked like a stereo receiver. This is a VERY sensitive receiver and with the CW filter, truly selective.
However, the single conversion design means the bands flip from left to right and right to left, and the USB-LSB switch flips from band to band, with color coding.'
While the SX-146 was and is a competitive receiver, the matching HT-46 transmitter was quite unsatisfactory. CW made the rig run scary-hot, and the SSB reports were only fair. I ran a Ranger 1 on CW, and that was a vastly superior rig. Once I got an FT-301 back in 1978, I unloaded the HT-46 and never missed it.
However, because the SX-146 was such a wonderful receiver, I hung onto it, and stupidly tried to make it more sociable by stripping the cabinet paint and covering it in walnut contact paper, and placing it in my living room.
The receiver sat in a box unused for more than 20 years, surviving two divorces as I just could not bear to sell it. Six months ago, I opened the box and plugged it in - and darned if it wasn't just as sensitive and selective as I remember. If you see a SX-146 at reasonable (~$100) price, snap it up. But stay away from the HT-46.
Better if you can find one is a Drake 2B from that era. THAT is the receiver I wish I had back. But it was one of two rigs I loaned at various times to kids trying to get into the hobby - and they moved and didn't return it.