Price Paid:  $0.00

Summary:
What a gem! This thing has more power than a demented dictator. I purchased this unit today on Craigs List for $250 in mint condition! I jumped on it based on the reviews that I read here on Audio Review and Stereophile. It just churns out the music with fantastic airy highs and thunderous bass. Placement and separation of the instruments are phenomenal! I am awe struck over the soundstage that it reproduces. I lost my job a couple of years ago and had to give up my Audio Research, Krell, and Rowland equipment! I reduced myself to Kenwood and Sony. Audio suicide! I have been trying to economically put together a system that would at least satisfy my ears. When I came across the Adcom my mission was completed. If I were to take the blindfold test I would not be able to tell it from my Krell or Rowland. Oddly enough it sounds like the two have combined! It has the same type of Krell bass slam and the finesse of the Rowland 5. Now I can sit down and actually enjoy the music rather than criticize it and complain about what I need! I would love to find another one and run them as mono amps. What a treat for the auditory canal that would be. I highly recommend this unit to whoever is considering listening to it. It will not disappoint, just delight! I have had over 100 different combinations in the past trying to achieve a certain sound that I have in my head. Mission accomplished. The price is a spit in the ocean compared to the past amps that I have owned. My hat goes off to you Adcom.

Price Paid:  $500.00 from Friend / Amplifier t

Summary:
I buy and sell classic audio gear on eBay among other places. This means that I am constantly changing speakers, PreAmps etc. I need a good powerful amp of signifacant quality, one versatile enough to play any speaker on the planet. I owned several of Adcom's earlier amps including the GFA-1 and 1A. I gought the first series Definitive Technology BP-20s when they first hit the market so I bought a 555 Adcom to power them and was never disapointed. Always plenty of power to drive the BP-20s to wickedly loud levels cleanly and effortlessly.
As time passed and after continuous upgrades into a full blown HT setup I found I longed for the good stereo sound again, simple and uncluttered in my office/computer room. I remembered my experience with the 555 so when my friend was selling mint 555IIs I bought one. I remembered my old JBL L-112s and found a pair of them. Next I needed a decent PreAmp when along came a Sony TA-E77ESD, now we are talking pushing a classic pair of JBLs with enough power to light a small town everything came back. The JBLs were a bit dated and I wanted a more hi-res speaker so I put a pair of NHT Super Ones on this 555II and WOW! those who think the NHTs are a little thin havnt heard them behind a 555II. After dozens of different speakers I now use Sonys SSTX7S a overseas MTM model with glass cones and I am here to tell you that the sound is extraordinary, comming is a hand built pair of 7in 2ways that my friend is building for me and I expect this 555II to sing with these as well.
I read every review written here about this great amp. I hear things like grainyness etc. when I hear nothing but clean, clear music out of everything I put on it. Of course there are differences between different speakers but I never thought for a moment that any thing other than good was comming from my 555II.
I see people comparing this 500 dollar amp to multi thoasand dollar amps, somehow the Adcom can't cut it when comparing it to a amp costing ten times the money, call it mid-fi, low-fi or what you will. I call it great. A great amp at a great price period.

Strengths:
Versatility, power, great bass and clean clear mids and highs, big bang for the buck

Weaknesses:
As to what?

Similar Products Used:
Fort'e model 3, Adcom 555/565, Rotel RB-981/1080/985thxmk2/Anthem/ Accurus 200x3

Price Paid:  $350.00 from private - in sweden

Summary:
awesome amp. crazy with power and hifi...

Strengths:
controll, absolute power, everything

Weaknesses:
thump when turn of, but whatever.

Similar Products Used:
yamaha

Price Paid:  $0.00

Summary:
In 1995 I was auditioning stereo power amplifiers for my Carver Platinum Mark IV speakers. I owned a pair of Carver Silver 7t's which were not a good match for my speaker as they both had a peak around 3kHZ. I borrowed these used 555II amps from a local dealer to audition. Right away I could see that they had a richer tone and better bass than the Carver amps. However there was also a noticable grain that was not evident with the Carver amps. At least the low treble peak was reduced. I then obtained a late production Parasound 2200 stereo amp and elected to go with this as it was as smooth as the Carver but had the richness and freedom from low treble boost as the Adcom. The Parasound amp also appeared to be more refined. Later after I biamped my speakers I was able to audition a Rotel 990 amp that was faster than the previously mentioned amps although a little roughness compared to the Parasound or Carver products. The bass was better deliniated also. All these amps tended to congest with large scale orchestral works. I liked this amp but it is far from perfect. My speakers, especially since I biamped them, can reveal differences in amps. A Krell FPB 200 that I tried on the top end of my speaker made significant improvements in many areas (although it is forward in presentation).

Strengths:
Fairly solid sound with good full bass and some continuity and good tonal quality.

Weaknesses:
Somewhat grainy, lacks bass control, congested with large orchestral works, OK treble.

Similar Products Used:
Parasound 2200 (late model), Rotel 990, Carver Silver 7t

Price Paid:  $400.00 from Audiogon

Summary:
The Adcom GFA555II never ceases to amaze me. It has to be one of the best values out there in amplification. I have tried much more expensive amps only to fall back on this one. The real key to deriving the best sound from this amp is to match it with the right speakers and preamp. The Adcom preamps do a fine job with this power amp but after experimenting with different preamps, I found the Audio Research LS1 pre is the best match for high end sound. The LS1 with it's one tube creates a much more lush midrange and far more grainless highs. (I also tried the LS3 and it wasn't the better of the two with this amp). I never thought the 555II could be so capable of this calibur of sound! I have four large (floor standing) Klipsch speakers and it is well known that Adcom and Klipsch make a great synergy match. I feel now that I have a very musical system without mortgaging the house. I highly recommend this amp to anyone including those that intend on spending much more to check out this one first.

Strengths:
Adcom's best sounding power amp ever. (can be compared to much more expensive amps). Sound quality, Build quality, Great bottom end.

Weaknesses:
Absolutely none.

Similar Products Used:
Bryston, McCormack, PS Audio, Conrad Johnson