Adcom?

I've had a first generation 555II paired with a GFP-750 in my vinyl system for many many years and they've been completely trouble free, not even a blown fuse. I recently bought a tube preamp for my other/main system and tried it a few times with the Adcom and it really makes it sound much sweeter. My music choices have changed significantly since I bought the Adcom set and I also used to listen to my music much louder and always felt the Adcom got a bit edgy at higher volumes. With the tube preamp I can crank it up real loud and the music never gets grainy or harsh. Made me wish I had bought a tube preamp instead back then. Something you guys might want to try.

That's something I'm sensitive to, grainy or harsh highs.  I got rid of an Emotiva amp that got harsh at higher volumes and it drove me nuts because back then I was under the impression that all amps sounded the same.  I also had an Onkyo receiver that impressed me until I realized it sounded different than my main system.  Grain, I'd never heard it before and suddenly I realized that these audiophiles speaking of grain and such were on to something.

That's how I got turned onto Parasound.  Not harsh, just smooth full sound.   These days, for a preamp I've got the Parasound Halo P5 for the Adcom amp.  Not harsh in this set up.  But I've also noticed that the amp responds to different cables.  If I put in silver wire IC's and silver plated copper speaker cables, at least with my speakers it can get bright with some recordings.  With Morrow MA 3 and 5, and copper based speaker cables, there is no brightness.

I don't believe my old Parasound amp was as responsive to different cables, it's another way to fine tune the system.  I've heard tube components do have a different sound, but tubes are higher maintenance and such, not my cup of tea.

Any word from Adcom on who’s designing the new models ?

The new models are almost entirely based on the classic models from their heyday, except with upgraded wiring and circuitry to meet current safety standards, etc.  Also upgraded circuit boards.  Still, the new models have improved specs in some areas, so it's obvious that some engineers are tweaking them, but Adcom only ever refers to their team of engineers.  No names are mentioned.

Earlier I may have given the impression that tubes are less than ideal in my opinion, but it's obvious that many love the sound and options of tube rolling.  I'm sure the tube sound would compliment Adcom amps, if one rolls that way!

I've got 30 hours on the 555SE at this point, and I've been changing cables and speakers as I go so it's hard to notice if the amp is improving.  But I'll tell you this, Ascend Sierra 2 speakers do not like Wireworld Oasis 7 speaker cables.  Strangest thing I've ever seen in my system.  A muted somewhat non-dynamic sound is the result, but swap in the Tress cables and everything missing is back.  The Totem Rainmakers are fine with either cable but do sound better with the Tress as well.

All in all though, the amp sound quality is quite good.  Open, fine imaging, air around the instruments without grain.  It's obvious why this design put Adcom on the map back in the day.  I don't crank it up in my smaller room, though, peaks of around 82-84 db are enough for me.  There's an old review by Stereophile floating around regarding the original 555 in which much praise is offered, and favorable comparisons with the high end gear of the day.  I'd say it's worth reading.

In this hobby I've made some missteps, and it's my hope to leave my impressions and results here to help others like myself who are looking for good options.  IMHO, these Adcom amps are a worthy contender unless you're looking to achieve that last 3-4% of magic in your system.  In that case, a reputable dealer with experienced staff may be your best bet, along with a much higher budget.

I’ve owned the Adcom 555 since it was first made,bought it used. After reading a favorable review of a Musical Concepts Modified 555 in Absolute Sound I sent it too them and I had it modified. Very impressed with the results,gone was the grain in the treble and the bass had more slam and tighter. They made it dual mono too. I still have it in storage and I hard wired a Card as power chord into it.
I just got my Adcom 750 pre amp,a Nelson Pass design,back from Musical Concepts last month after having it modified to the Elite level and it sounds Uber. Sounds tube like with detail and warmth,very holographic with separation of instruments. I had owned the 750 since buying it from the first run with the Blue circuit board and Stereophile rated the 750 Class A.
Adcom was my first foray into affordable high end and holds a warm place in my heart.