Can't speak for the 5500, but the 5802 is MUCH better than the 5800. All of these amps are relatively brawny and will make a lot of sound for the money spent, but I wouldn't call any of these amps "musical".
As to buying used or on an auction, take a look at the seller's feedback ( if they have any ). People that have good feedback are typically good to deal. As such, most wouldn't want to risk their otherwise good reputation just to make a quick buck by posting misleading / incomplete info in their listing. Like anything else though, you could be the one out of the whole bunch that ends up getting "shafted". My suggestion is to find out who you are dealing with and as much info about what you are buying BEFORE bidding or finalizing any transaction. Sean
My own experience with Adcom is that they sound pretty much like sound reinforcement amps. Coupled to goodish speakers they're likely to be bright and tight--design considerations to help them cope with slow, tubby road speakers.
They wouldn't be my choice for music.
That being said, some very critical listeners use PA amps to drive passive subwoofers.
But if I were going to do that, I'd go to Mars Music and buy a Crown K2. Dead quiet, electronically and mechanically, built like a tank, able to drive any load known to man, and with damping factor enough to tame even the most bloated sub system.
Look, in a way you can't have it all. 200 watts, good to 4 ohms, under $800, warranty.....(however you did not mention your other equipment, sound preferences, etc).
if you're buying used, there's nothing wrong with Adcom in general. obviously a bad unit is a bad unit, no matter what brand it is, so only deal with reputable sellers, otherwise it is a gamble as you say.
it is hard to get 200 solid and clean sounding watts that are stable into 4 ohms and lower without spending about $2000 retail (the Marsh amp A400 I believe is a good design and made by cheap labor/assembly costs in Thailand so the price is relatively low). The 5802 is a little less than that retail.
Sean's advice though is good....and ask a lot of specific questions about your intended purchase, like has it ever been fixed, modified, blown up, whether the seller is the first owner, why selling is also sometimes indicative of condition though not always easy to get an honest answer.
also big items are expensive to ship and they need very good packing.
parasound is also a good amp, with high power for few watts, nad, etc.
For the money, I would seriously consider a used Classe CA-100. You can find this outstanding amp selling typically for around $550 - $700. In fact there are a few up on Audiogon for sale right now. They are available in black or silver.
I owned a CA-100 at the same time I owned a heavy Adcom 5-channel amp. The Adcom sounded compressed and thin compared to the Classe. In fairness, this was a multi-channel Adcom intended for home theater vs the 2-channel Classe. I've owned a number of Classe amps over the years (DR10, 10, CA-100, CA-200, CA-300) and they never disappoint. And for the money, you'd be hard pressed to find better, IMHO.
used B&K EX442 can be had for ~$400-$500 used. It smokes the Adcom...
As I've commented before in these pages, the audiophile community tends to disparage some of the entry level, yet high-value products, available from various manufacturers. Adcom belongs to this "Rodney Dangerfield" group -- it tends not to get much respect. However, you will find that many of the regulars who contribute to this forum have owned Adcom preamps and power amps at one time or another -- myself included.
Unlike some of the other contributors, I have also been a retail salesman for Adcom equipment. Adcom has had some QC problems in recent years, which began after they shifted their manufacturing from one of the high-quality assemblers in Taiwan to a facility in mainland China. Having said that, I'd also say that Adcom seems to have addressed most of those problems, and continues to do a a pretty decent job of continuing to design and sell solid products for fair prices.
Based on my experiences with Adcom amps, which involves a LOT of listening hours with various speakers, I'd say that a used 5500 power amp is a hell of a value. For around $650-750, there are very few amps that provide 200 wpc of clean signal, and will handle speaker loads as low as 4 ohms with aplomb.
I am less enthused about the 5802, not because it's performance is poor (it's performance is actually quite good), but because it has a lot of competition at its price point. As Sean noted above, the 5802 is a better amp than its predecessor, the 5800. It is still, however, a very large amp and it produces a lot of heat for a solid state amp. It thus requires a lot of space with good ventilation.
I have both bought and sold Adcom power amps on Audiogon and E-bay, and had good experiences in all instances except one (a dealer that slightly misrepresented the exterior condition of the amp, tho' it worked fine). If you make a point of talking -- by phone -- with the seller, you can usually get a better idea about the fairness of the deal. You should also check seller ratings, since a lot of good feedback is usually a sound indicator of the seller's honesty. Also, Audiogon has "verified members", whose addresses and credit have been verified.
My complaints about Adcom is the cheapness of the single ended(rca jack) connectors on their products. I have had two instances where the connector has pulled of of the back of the unit. Maybe my experience is unique. One instance was on digital output of a GCD 575 cd player, the other was the input jack of a GFA555 amp.
I have also owned the GPA565 preamp, good sound for the money. Before buying Adcom new, I would look to buy used from other manufactures....Classe, Bryston etc.
I owned an early Adcom 5500 and considered it a decent sounding and built amp. It hummed in my system, but then all amps seem to hum in my system-- it's an electical supply problem in my case. I wouldn't hesitate to buy adcom, but I agree with Abecollins (above), and would look for the smoother sounding Classe' CA 100, 150, or 200. I would put these in a class with McCormack DNA-1 and 0.5 amps-- also recommended. Good Luck. Craig
My experience with Adcom is similar to Sdcampbell. I used to sell Adcom products in a few retail audio stores. I changed professions in 1995. They use to run many contests for retail salespeople and along the way I had picked up a number of their components through these contests. In my opinion, their DA converter, the 600 model at that time, was a great buy at its pricepoint.
Their amplifiers and preamplifiers were solid products that had few mechanical issues. The 555 amplifier sold itself. I found it to be a bit harsh compared to other amplifiers that we sold, but it must be said that those amplifiers were more expensive and less powerful. I am told that their current line is well produced.
I also agree that auctions are risky only if trust between the buyer and the seller is not established. I have had many positive experiences working with Audiogon members. That has been predicated by conversations either by phone or on the internet with buyers and sellers before committing to sales.
why are you stuck on power? i have seen quite a few krell 100 watt amps for 800 dollar range. they would kill a 900 watt adcom. i still say buy a chiro c-200 for 450 to 600 bucks. yes it is only 140 into 8 and 280 into 4 but it will simply outperform the adcoms in every way. take the extra cash and upgrade the rest of your system. i agree with the crown amp idea as well. they have tons of power and are dead reliable. i have a crown macro reference on a home theater sub. it beat a krell kst in to the ground with plenty of juice to spare. good luck.
Kirk, i think that you and a few others bring up a very valid point. Since many folks that are looking at Adcom, NAD, B&K and other like products are probably not very well versed in gear, they are still pretty reliant on product specs. This is not to say that specs are completely meaningless or that these are bad products, but that one should NOT rely on "advertising claims" that manufacturers provide you with.
As such, anyone that has played around with a half dozen different amps can tell you that Brand X watts are not the same as Brand Z's watts ( even though they are supposedly measured the same way ). It is not so much how "powerful" an amplifier is, it is really how well it interacts with the rest of the electronics and the speakers. I am talking about both the ability to drive the load AND sound good doing it at a wide volume range.
With that in mind, most of us have all run into "smaller" amps that seemed to perform with a LOT more "gusto" than other "big" or supposedly "beefier" amps. Since Classe' was also mentioned, i'll use them as an example. At one point in time, I had a Classe' 70 ( 75 wpc @ 8, 150 wpc @ 4, 300 wpc @ 2 and 3 dB's of headroom ). While i did not particularly care for the tonal balance of this particular amp, it actually drove some low impedance / low sensitivity speakers that i had better than a "much bigger" Bryston 4B ( 250 wpc @ 8 / 400 wpc @ 4 ). Not only did the "little" Classe amp sound cleaner, clearer and less strained at volume, it cost less money. If the sonics would have matched what i was looking for, it surely would have ranked ( in my book ) as a "giant killer" given its' low power rating and reasonable cost. Since others have different systems and different preferences, it very well MIGHT be a giant killer and a bargain to them. Sean
Actually, I agree with other posters who have suggested looking for alternatives. If power for low bucks is the main concern you can get a B&K Reference series 4420 for under $600used (220 watts per channel, very solid, perhaps a little dark). For more money, but better sound I would go up to the Bryston 3B-ST (a little less power, but a really fine product with truly musical sound) for $800-$900 used or the Bryston 4B-ST for aroun $1300-$1400 used (massive power, but very musical). The Brystons also come with a 20 year transferable waranty, so buying used is much less risky than with other brands.
If $$$ was a concern I would take the B&K Reference amp over the Adcom, most any day. I just heard a B&K Reference 2220 (2x220wpc) and was pretty impressed for the money. I'd rather have it than the monster adcom, unless I was driving a stack of subs, or something.
BTW, the 2220 was driving a pair of Maggie 3.6/R's.