I built one in 1969 and it was a great receiver at the time. 50 watts RMS into 8 ohms a side, THD 0.5.
Great FM tuner. With a double extended zepp antenna I could pick up stations in stereo from Cincinnati while living in Indianapolis. Used it to drive a set of Acoustic Research 3A speakers with a Dual turntable, Shure V15 cart. Great sounding set up. Bad news was heat. If you drove it hard it would get hot. It had thermal cutouts on the output stage heat sinks for self protection. However it liked to go through power supply filter caps on a regular basis and sometimes talking a power supply SCR with it. Other problem was low-level signal leakage across inputs. The phono input would pick up the FM signal. Finally did a mod where I could stop the FM oscillator while using phono input. Only bad part is lost all the gear when my apartment got broken into and it was stolen. :-(
I never owned one, but coveted one. 1969 precedes the tightening of amplifier rating rules that the FCC established in 1974. I did build a 1970 Heathkit color television and a lesser receiver in 1973. My go to first stereo was Dual 1019 tt, Shure cartridge, Dynaco PAS3, Marantz 8B, and AR4x speakers.
I owned one and kept it for quite some time. Built it in 1972 after marriage and college graduation. Replaced with a Dynaco PAT-5 preamp and a Dynaco Stereo 400. That was some fine audio! Also built the JBL 14" 2-way speaker kits from Heath that were used with both the Heathkit and Dynaco gear.
Also built a couple of Heathkit TVs. A bit quirky, but good performance for their time.
Theater in Progress: Emotiva XMC-2, CMX-2, CMX-6, VSUB-1, BTR-1 Sherbourn PA7-350, PA7-150 (2), C-12 (3) Sony UBP-X80 Panamax M5300-PM Klipsch La Scala I LCR ; Heresy I surrounds (6) Tuba HT subwoofers (2) PSA XV15 subwoofers (2) miniDSP 2x4HD
The schematic reminded me of the built in test meter function (aka signal strength meter) you would use to verify your build of each board was done correctly. Dynaco and Heath really were the leaders in high quality gear at a decent price for a few years in the early 70s.