Also copying something I wrote on another thread a few days ago below. Do not believe anybody that tells you that you absolutely MUST have a complete restoration job that will cost several hundreds of dollars (at least) to replace every capacitor/resistor etc...First of all that will change the sound that the receiver was born with. You can definitely find receivers from the 70’s that still sound wonderful with no work done to them...it is a crapshoot thou. I have no experience with the Harman Kardon listed above simply because they look inferior to their counterparts...so I stayed away. They could sound great thou. The IC CHIPS for FM reception on several Harman Kardon Receivers from the 70's no longer exist...so if RADIO is important to you do your research first (on AudioKarma)
Your best place for info on Vintage gear is AUDIOKARMA....not Audiogon....not even close. Don’t waste your time here. This post would have 50 replies in a week on AudioKarma.
I have over 50 of these mid-late 70’s in stock and have owned well over 100. The worst sounding brands to me are Yamaha "Natural Sound" and Sony receivers. Tandberg is another dog. Kenwood is better than these BUT middle of the pack for most models...exceptions below.
It really depends on what you want to hear. Pioneer and Marantz sound great but far from the highest resolution.
Luxman will give you the greatest "detail". You will hear things with Luxman that will be masked by most of the other brands.
Here are some of my Favorites to seek out.
Best bargains (which sound Better than the best Pioneer/Marantz): SANYO JCX-2900K, ONKYO TX-8500 either version, Sherwood 9910.
Others are Any TOTL Sansui’s like Eight Deluxe (Not Eight), 9000 Models....not cheap. NIKKO NR1415, Kenwood KR-9600 and 9050, Technics SA-800, Luxman R1070/1120.
Pioneer - SX1250, 1010, Marantz 2285, 2325, 2330
I pair all my receivers with JBL Monitors (4412, 4312A, JBL 166)
Hope this helps you get started.