[OlesonMD]

Does anyone have experience with this Nelson Pass design?
How does it hold up over time? Repair history? Overall sound quality?

I'm considering buying one used. Any pricing history?

[Scottdazzle]

I owned that amp for about 10 years.  It drove Thiel 2.3 and Thiel 2.4 speakers during those years.  I sold mine for about $600 three years ago.  It was powerful, rugged, quiet, and utterly reliable.  Sonically it is a little less refined than the Odyssey Stratos that replaced it. I have since switched over to a Music Reference tube amp that I consider superior to either of those except with regard to bass tightness.  Hope this helps. 

[rwdrey]

I had one for 5/6 yrs. Paid $1500. Sounded very good, built like a tank & QUIET. Never had any issues with it. Sold it to a buddy a # of years back for $800. He's still using it with a Counterpoint SS preamp & a pr.of Paradigm Studio 100s. He luvs it & has never had any issues either. How much do you plan on paying $$? Good luck w the journey.

[OlesonMD]

I've been watching Ebay and the prices are running around $700 - $800. Have also been watching the GFA-5500 and the 555II. These are running anywhere from $350 to $550.

I read that Adcom does not make good products anymore, and the best buy is a used 555 or 555II.

I've never heard Adcom. All of my gear is B&K, which I do like. Also looking at a Vincent SP-331 (never heard that one either!).

[Phil A]

I believe the original 555 was actually made for Adcom by Rotel.  I have one for the left and right channel in the bedroom (surround) system to drive 4 ohm speakers for the left and right as I also need something not too deep to fit behind the center channel and underneath the TV.

[Phil A]

The 555 was actually designed by Nelson Pass -  http://www.diyaudio.com/forums/solid-state/5280-adcom-555ii-nelson-pass.html

and is about 25 years old - http://www.stereophile.com/solidpoweramps/678/

[rwdrey]

I had a few pieces of Adcom gear years ago, including a GFA-5500II(also a nice amp). It was very well built, reliable , & affordable.
Don't know anything about Adcom anymore. Are they still around? $700-$800 sounds like alot for an amp that is probably around 15yrs. old or more. Pretty sure the GFA-5800 retailed for $1600. Back in the day B&K & Adcom were very similar products, good sounding, well built, & alot of bang for the buck. If you are happy with your B&K gear, I really don't think the Adcom will be a nite & day difference. And if you gotta pull the trigger, I'd look for a $300-$350 GFA-5500II. You won't be giving up much to the 5800. Good luck.

[AVnerdguy]

A very nice amp with tons of solid power. If you get a good deal it's definately worth going for it. However, if it requires service in the future be aware that the output FET transistors (that make it sound so clean) are no longer available from typical sources and it can be very expensive to repair.

[HAL]

The GFA5800 has a fan that was audible in my quiet room.  The newer GFA5802 has no fan and higher output power.

Just a thought.

[macrojack]

While you're at it look at Perreaux. Surely better but for some reason just as cheap or cheaper than Adcom. Hafler is worth a look too.