That was first published in 1987 and the other "bargains" mentioned, i.e. B&K, Shure, Superphon, were truly really good for the money.  I owned two of those pieces.

I always enjoyed Corey's writings. Adcom was tough to beat (no pun) back in those days (when their products were made in AZ). I owned the 555 power amp and 565 pre-amp in the early 90's.

Happy Listening!

This was also when (1983-1997) HEA had it’s biggest and most actively productive membership. I was so disappointed when the quest for $$$$ became the driving force instead of the sound that so many of these companies provided. The basic models sounded much better than the over built ones and the designers knew it, but the pressure was on to get the gravy train in full gear.

Fortunately the mass produced companies picked up where these basic audiophile products left off.

Michael Green

Oh, I should probably add this for a point of reference. During these years I had my own HEA stores. I spent a ton of money trying to get the most out of the pricy products, but started to feel guilty selling them when I knew the basic models were able to out perform them. Same thing happened as I was doing trade shows. Because I was providing a popular acoustical product the high enders wanted me to do their products in my own rooms, but again it was a conflict for me.

Not sure if the OP is asking for opinions or recommendations but either way the 535 was actually a better amp as compared to some of the higher power models like 545 or even 555. It is also more easily and cheaply upgradable. I've owned all three models (still own 555) and for moderate listening levels the 535 has a fuller and cleaner sound than the 545/555. 
Sorry gentlemen,but Thresholds were better in the day.
compared both many times back then and always picked the Lwr pwr ones for better overall sonics and build qualities.

Nelson pass is still a “Benchmark” for solid business practices and customer service,unlike some of the questionable companies of today that just come and go and don’t stay in business long term.

Happy Listening,
Back when Adcom was buying a lot of full page ads, I had the opportunity to use one for two weeks in my system alternating with my Mac 2105, which was pretty old even then. I can't recall which model, but it was well over 100 watts per channel. Anyway, the sound was thin, hashy in the treble, and overall not even comparable to the Mac. It still makes me wonder where all of the praise is coming from. At the time when they were popular, they were well priced amps for people who couldn't afford a higher end, higher powered amp.

I owned an original 535 ( as well as other Adcom models ), and purchased a series 2, which had many upgrades ( circuitry ), including better rca inputs, speaker binding posts ( and eliminating the speaker switching ), and to my knowledge, heavily biased to class a for the 1st several watts. I still have the series 2 in my amp collection. Working within its limitations, it is a very good amplifier, slightly dry, but very accurate, and has always run hot. 

Funny, the two amps Corey mentions at the end (Electron Kinetics Eagle 2A and PS Audio 200C) I own. The 555’s are notorious for having their power supply filter capacitors go bad (be careful about hooking one up to a pair of speakers you love), which I had happen; I don’t know if the same is true of the 535 (or 545). Anthony Cordesman (as usual attempting to get a "scoop") grossly over-rated the original 555 (dry, grainy, coarse. Okay for a sub perhaps, though not as good for that as the Eagle 2A), and was quickly put in his place by JGH and Larry Archibald.

The Eagle 2A and PS Audio 200C can be had for about the same price as a 555; both are better amplifiers.

I had a 555 ii and never warmed up to it.  At higher volumes, it got thin and etched sounding.  I replaced it with a Classe 10 amp.
For the price it is probably a very good deal.  His comment that "The B&K amplifiers, as I have often said, sound tube like" makes me think that he have never heard tubes before and I take that as a poor description.  IMO SS that sounds like tubes means that they sound more dark, and soft sounding unless it is First Sound.

Happy Listening.

Some great amps are being mentioned on this thread. I still pick up some of these to tune with.

On the B&K ST140, if you were lucky enough to get Steve’s design of the amp (first 6 months of production) you will see why people said it was one of the best amps for tube sound of it’s time. And the other major plus was how well it mated with the excellent sounding preamps of the day. Stan Warren also did a nice job with his 220. The list of amps during that time I would say were among the very best HEA ever offered at any price. Names are floating through my mind by the scores.

On the 535, I think most here have nailed it’s performance. I think this is the best product Adcom ever produced. The 555 never made a dent for me, but when listening with AC I understood where he was going from his point of view at the time. Some times you have to be listening with the guy themselves to have them explain where they were going, and what they were looking for.

One amp that totally went under the radar, that I stumbled across as I needed something fast to plug in then totally fell in love with was the Marantz MA700 mono block. I’ve probably own 50 of these for myself and sold another 100 (maybe more) sets to folks. An absolutely killer mono block to tune. I think I used this amp in 3 or 4 shows. I also hooked up 5 or 6 studios with these.

As far as I am concerned this thread should live on forever so folks can learn about the golden age of HEA.

Michael Green

I see Adcom is having a bit of a renaissance on the forums lately, I find it rather encouraging that there are companies out there making good sounding gear at an affordable price. I have owned a gfa 555 and a 545 and thought the 545 sounded nearly as good as the upgraded Odyssey Stratos I had at the time.

A question about the B&K st140, is it true that it was a copy of a Van Alstine design?
In 1985, or thereabout, I owned a pair of Audioplan Kontra Punkt mini monitors ($500) that I heard paired with Threshold amplification. I could not afford Threshold then and from great reviews got the Adcom 535. Well, the 535 could not produce the stunning presence and focus that I heard from Threshold. So, a night and day difference between the two.
While a product might have the same name on the front as did another product from years ago, the question is rather whether the two products share any design DNA or even the same company principals (and principles, for that matter).
I owned a few 535s (formerly my main amp years ago with the Adcom tuner/preamp, also used one as a recording studio amp and their great as a utilitarian extra speaker amp) and after moving on and selling most of them over the years I was down to a 535II (more standard binding posts) and a clean 5300. I think the 5300 is under appreciated and I wound up keeping it over my last 535 as it simply sounded better. Now it’s a backup/SS reference amp that drives outdoor speakers and is simply a killer amp. Note that clean versions are still around and are very inexpensive on the used market. Highly recommended. I also owned an Electron Kinergetics Eagle that developed  issues and I traded it for an Acurus A250 that also had issues, although covered by warranty. That led to another couple of 535s, including the MKII, and a Forte Model "55" which was a great amp. After that it's all tubes (the 5300 being the exception).

Really? I had an original 535 and never considered it worth beans. I've had hundreds of basic amps, most of which I've made but plenty of commercial designs and I have to say that the Adcom 535 was utterly undistinguished.
The original preamps that they made, the GFP1 and 1a were both great for the time and the price. The 565 preamp was stellar for the time. The GFA-535? No so much.
I can't find it right now; but I recall reading an article on Human speakers and their designer/builder/owner Huw Powell. The piece mentioned that Mr. Powell has one Adcom system in his office and one in his shop. I wish I could remember the models; because I consider this to be very high praise.