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
The closest I come to your list was a B&O turntable with the non pivoting tonearm and snap in cartridge. I liked it a lot.
Aside from that was a Quad 303 preamp and a BGW500D amp that brought me lots of joy. The rest is quite foggy.
I know this is not from your list but, see what you started.
Wow, I'm really enjoying everybody's comments, thank you. I particularly like the venomous reactions to the Phase Linear amps . . . as I think it's in so many ways the poster child of 1970s solid-state amplification.
Yet, it's earlier repuattion does not appear to have survived time. Just a question: why is that? I admit that I have not critically listened to Crown gear recently nor compared it to my current gear. Perhaps some of the oldheads out there can tell me why the old vintage Crown gear has fallen out of favor.
Bifwynne, these sorts of questions are what I had in mind to discuss when I started the thread . . . and I'd like to try as much as possible to avoid the subject of NFB, as it has a way of hijacking threads. Specifically, I think the "1970s transistor sound" is related much more to poor linearity in several key circuit areas, principally the "quasi-complementary" (all-NPN) output stage and its inescapable notch distortion.

But the Crown gear is an excellent subject, especially as it compares to Phase Linear . . . I have my suspicions that Bob Carver actually derived his designs from the Crown DC-300 schematic. They both use quasi-complementary output and driver stages, although there's a subtlety in the Crown design that's not immediately obvious: the drivers operate in Class A and in parallel with the output stage through the crossover region, smoothing out the notch distortion to a significant degree. It also makes the whole thing far less temperature sensitive for its bias conditions.

Although I don't know the exact chronology, I find it interesting that when Crown added an opamp front-end to the DC-300A (and D150) that Phase Linear followed suit by doing the same thing with the 700 Series II and 400 Series II. But Carver's amps still show the earmarks of a cheap copy, especially how he cut costs significantly by simply using an electrolytic to bootstrap the voltage-amp load, rather than the true current-source transistor powered off a separate supply rail in the Crown design. Carver was also obviously having stability issues with all these amps, as shown by the ferrite beads and picofarad-value capacitors "liberally sprinkled throughout the schematic" (to borrow an expression from Douglas Self).

All in all, from today's perspective both are dated designs and have a couple of the same flaws, but the Crown is a thoroughly well-optimized and beautifully engineered amplifier, and I think this shows in its sonics and its remarkable reliability. I'd say that with easier loudspeaker impedances, one could still do much worse than a DC-300 today.
My sonic memory of solid state amps from that era is that they never pleased me as much as the tubed Dynaco amps from a decade before.

I had only experience with solid state amps like mid 70's Pioneer beheamouth receivers, Yamaha A1 integrated.I was a newbie.
Before that it was a mono ,tube system built into a tv console. when I was growing up.

The solid state amps of the day ,never had the same sense of realism as the old tv system had, but it was newer and just had to be better and so I left it at that.I was a newbie.

Then a friend of mine got a used Dynaco stereo 70 and Pas 3 pre amp and his Ls3/5a speakers went to a new level.
We had the same Yamaha intgrated amp and speakers, cables etc.In those days if I heard a sound I liked, then I went out and duplicated it.I was a newbie.

So I went out and got a tubed Dynaco set up and was quite happy.

In retrospect, I should have quit while I was ahead.

But being a newbie, I flitted from one new "best" system to the next, and near the end of the 70's or early 80's bough a NAD 3020.

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.

Sure there's lots of features and lights and bells and whistles and shiney knobs, but at the end of the day, it's the sound that comes out that counts.

But then again this hobby has verred so far off the path from where it was when I started that, trying to achieve the sonic truth has become a no no, and any gear that is not coloured and covered in a hazey cloud of electronic mist is seen as too analytic and fatiguing.

I'll take my coffee black please, just make it a premium blend.
Transaudio-was that Trancendental Audio on the Niagara Blvd?
I remember it well when I was a newbie.

They had some Dan fellow working there that I think tinkered around with amps and may have sold a couple over the years.

I believe he is still at it to this day.
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.