How do we remember 1970s amplifiers?


I would be curious to hear some of the memories and impressions associated with the following short list of 1970s amplifiers:

- McIntosh "first generation" SS amps, MC2105, MC2505, MC2300, MC250, MC2100
- Dynaco Stereo 400 and Stereo 120
- Phase Linear 400 and 700
- Bang & Olufsen "slide rule" receivers (i.e. especially blackface Beomaster 4000)
- Original Ampzilla (not Son of Ampzilla)

I've chosen this list mainly because they cover a wide range of approaches to solving the issues of early semiconductor technology, and they were all pretty mainstream products in the U.S. I'm excluding the Japanese receivers/amps not out of predjudice; it's simply that the circuit designs varied quite a bit with each model, and thus harder to broadly classify their characteristics.

I'm interested in impressions of both sonic and non-sonic attributes, and a preferred ranking of the above, if you like.
kirkus
Sold my car to buy a high end system as a Freshman in college -1977. Talk about a killer dorm system. First amp was a Phase Linear 400....it flamed (literally) -- However, I thought it sounded very good. Then went with a fabulous Harman Kardon Citaion 16 amp and a GAS Theadra preamp, Dahlquist DQ10's (Denon TT w/ Supex 900 MC cartidge). It was fabulous. The HK amp was a tank and sounded superb. I replaced it with an Ampzilla in the 80's and regretted it. The Ampzilla was always breaking and was not as smooth as the HK...much better mids with the HK. The Ampzilla was very transparent sounding and had major balls in slam and low end energy. BTW, I got the "bug" after owning a nice Yamaha receiver w/ Infinity speakers. The rest is history and am still spending way too much money on stereo gear.
Kenwood L07M (mono) was reasonable as was the Grandson of Ampzilla. I had heard the ampzilla, it was rough around the edges, I had heard Flame Linear 400 and 700B, harsh.
Pioneer had some old Class A amps that I recall sounding quite nice... They were Series 20 or 30, don't recall exactly.... Compared to today, no contest
My system in 1978 was a GAS Son of Ampzilla, GAS Theadra preamp and a GAS Sleeping Beauty cartridge mounted on a JVC Direct Drive turntable. Speakers were Rectilinear 7's. Never could get the 7's to sound as good or better than the old Rectilinear 3a speakers that I traded them for. I also had a Sansui Tuner which I should have kept.

I loved my GAS electronics, quite smooth yet revealing in their day. The piece de resistance of my system was my Teac reel to reel recorder (can't remember the model).

I was working in retail at a mom & pop audio store so I changed my equipment quite frequently back then.
Sweet memories....
I owned a Phase Linear 200B (which outperformed a Quad 405 in a straight shoot-out).
Lacee, thanks for bringing up the little 20W NAD . . . this is the perfect 1980s equivalent of the Phase Linear amps. I serviced these back in the day, and even had the "Power Envelope" decendent (3225PE?) as a test-bench amplifier for several years. In contrast to the big, "all technical" 1970s aesthetic, it was small, lightweight, low-powered, and simple-looking. But like the Phase Linear, it was cheaply made and unreliable . . . and the sonic signiture was filled with exactly the opposite types of problems.

I will say that the preamp sections were pretty decent, maybe even good considering the low price . . . but the power-amp section was an absolutely atrocious piece of engineering. The key "feature" was that it didn't have emitter resistors on the output transistors, and I assume that this was an attempt to reduce notch distortion. But even if this had been a good idea (which it wasn't) . . . they then chose the absolutely cheapeast big power transistors available (2N3055/MJ2955) that have poor linearity even by 1970s standards. The result is that even with enough idle current to make it run pretty toasty, it was still really operating in underbiased Class B, and put out a whole slew of nasty harmonic and intermodulation distortion products. This may have been "redeemed" somewhat by the single-transistor input stage, which guaranteed a big helping of even-order distortion as a big sugary coating for that rancid-piece-of-meat of an output stage.
Not as good or as pleasing a sound as the tube stuff, but still better than the solid state amps I had been using in the 1970s.

This is the reason I find the new fascination for 70's solid state stuff so perplexing.
From someone who was there and listened to that stuff when it was new and all the rage, and then moving on to better things,I just can't see the interest in any of it.
Well, selective memory seems to work both ways . . . we overwhelmingly shun what was in vogue in some eras, and romanticize others. One of the reasons why I mentioned the 1970s B&O receivers was because (like the NAD amps of the 1980s) they offered a modestly-powered, domestically sensible alternative to the "high knob-per-dollar" mainstream aesthetic. They were vastly better engineered than either the Phase Linear or the NAD, but had a few quirks of their own (esp. cultural?) . . . I'm wondering whether they're remembered similarly to some of the more high-profile [sic] pieces of the decade.