My take on the popularity of SETs was that it was driven, at least in part, by the first several years of digital recording (whether that recording ended up on LP or CD is beside the point). The first several years of DDD were atrocious: digititis, digital glare, call it what you will. The only thing to tame it was SETs. Now time has passed and things have improved some, but SETs still have that incredible midrange. And so it goes.
An Audiophile's journey
Well, How do I begin? First of all you english teachers out there just don't read this and we'll both be the better off for it. English grammer and spelling is something that I'm not well educated in. I will tell you that I'm a business owner and at 45 years old I don't hit a lick anymore so, all you proper spelling and grammer people just eat your heart out! Now let's get to what I have to say. I've been an audiophile since I was a kid in the 70s. My parents used to punish me by sending me to my room. It was grounding me for being bad. I was bad a lot! My Realistic receiver, BSR turntable, Technics cassette deck was my best friend. Oh, I forgot to mention my Advent loudspeakers. Anyway, I went all these years with solid state gear. When I finally got old enough to not be punished anymore(at least by my parents anyway) I got some Martin Logan SL3 speakers and a Krell amp. I just thought I had arrived! Bring it on everybody! Several years went by. I ventured into trying a tube amp on my SL3s. WOW! What revelation! It was a Rogue M120 Monos. I remember thinking why can such an outdated technolgy be so right in my rig. Then as time went by I got involved in this new website called Audiogon. Audiogon made it possible to buy and sell stuff at a minimal loss if you didn't like it. WOW! What an Idea. Poor dealers! This was late 90s early 2000. Those were the good old days. There were just a few of us excanging ideas and information. It was like an audiophile AA! I bought and have tried so many pieces of gear that I've forgotten more than others know! Then the SET revoltution came. Man, I fell hard. I've since went back and forth several times from SETs to solid state or push/pull tube amps always trying to find that nirvanna or fountain of youth of audio. Fastfoward through the great Bill Clinton years, I tried my hand at being an in home dealer and found that dealing with audiophiles was worse than babysitting children. So, that didn't last long. I still have some connections but, recently I've been blown away! A couple years ago I had a friend that got some popular UCD digtital amps to try and I thought they had great potential. But, still weren't my SET horn combo. Now this SET horn combo was a biamped system with a digital amp on the bottom (600Hz and below) and a SET amp on the top. It was, what I thought, the magical audio reproduction machine. Then a friend got a Spectron Audio Musician III SE MK II amp for his Aerials. He was blown away. He kept after me to hear his rig. Well, to make a long story longer I gave in and listened. I'm as fimiliar with his rig as I am my own. We decided to hear it in my rig. I didn't habe speakers suitable for this monster of an amp. So, I got some Dali Helcon 400 MkII for audition and we went at it. Well, to say that history was made is an understatment. I've since been selling all tube gear and living in audio heaven. I can't beleive that there is not the first tube in my rig now. My take on this is that solid state manufacturers were resting on there laurels during the late 80s and 90s. That why a 300B SET amp came along and all the people were freaked out by the great sound an 8 watt amp could produce. That great midrange! It's what brought audio out of the dark ages. Solid state has gotten on the ball since then. Digital has come a long way and is now sitting in the catbird seat. Sorry for the ramblings this Monday afternoon but, just had somethings on my chest.