Brands that have the least depreciation

ARc = Audio Research Corporation

As it has been said, McIntosh, Thorens, Marantz, ARC and others. I think particular models of brands are even more indicative of this. Some JBL speaker models, maybe the Garrard 301, some Marantz, Sansui, Pioneer receivers of the USA glory days of massive models, many of the models of McIntosh equipment. There is a vintage guy here in Ohio, Wooster Vintage Audio and he really finds great old Mac gear for resale.

I've had good luck with McIntosh over the years. It doesn't make it better than some of the other brands. I also don't think McIntosh sales are really driven as much by advertising as history. It's a brand that has been out since the 40's. Over the years they have developed a reputation for good quality and good sound (sound subjective for me anyway). Sometimes it's so hard to audition some of the other great brands because of distribution. I have the McIntosh 601's, and love them, but would I have picked another brand if I had the opportunity to listen to them for any length of time? Perhaps. In this price range more people (around the world) know exactly what they are getting from McIntosh new or used. That said, McIntosh still offers only a 3 year, non transferable warranty on their electronics compared to someone like Bryston at 20 years.

Back in the early 80s, Dynaco Stereo 70s could be had all day long for $50 - $75. Dyna MK-IIIs could be had for $100 - $125 a pair. I wish I would have filled my garage up with them at the time, and cashed out about now. 

Frank

100$ in 70's  is 500$ today .