JVC AX-R551 integrated amp from a late 80s rack system. It has all the crazy bells and whistles like a full graphic equalizer and audio level meter on a digital display, not to mention the "acoustic expander" button that seems to mess with the phasing somehow to expand the soundstage. The build quality is very nice for what it is and the audio performance is equally impressive. It's a very clean-sounding amp with exceptionally tight bass. None of that loose, flabby, tubby sound like my old Realistic STA-82 (which is still a cool receiver in its own regard). It's also rated at 120 wpc into 8 ohms, 20 Hz - 20 kHz, at only .03% distortion. Unfortunately, it has developed a high-pitched whine that comes through the speakers whenever the amp is on. It's not noticeable when music is playing, but it's very noticeable and annoying between songs or during quiet parts. I have a hunch that it's the caps, but I don't know whether it's the big power supply caps or others and I haven't gotten around to looking into it.