Rediscovery, Adcom GFA 555 MKII

If you want to play loud try some pro audio amps with the Maggie's. It is amazing how They just eat the power

 

Turntable is set up and running in this system with the Shure VST-V cartridge and a new original stylus. I really like having its stand setting solidly on a concrete floor! Sadly I now want to keep my turntable down here, no worrying about footsteps anymore.

I invited a few old friends over for some fun, food, and music tonight.

I had played some of my records for a few hours earlier on to break in the stylus a bit. Certainly needs more hours.

While we shot some pool and darts feasting on beverages, wings/pizza from the local pizza place I started on some of the vinyl they brought with, but there was just too much noise from all of us for any real serious listening. But it still sounded pretty good.

We finally settled back for the short remainder of the evening to listen to a few select LP's of theirs a bit more closely. First was a really clean copy of Beatles Revolver. I'm not a Beatles fan, but I need to get this. Wow, Taxman sounded fantastic. Good Day Sunshine really blew my socks off.

Next up, Steely Dan Aja, I'm so glad someone brought this as my copy is worn and noisy. I love this LP and it did not let down.

Last LP of the night, honestly I cringed to put it on....was a sealed copy of Dark Side Of The Moon. I've heard this so much over the years I gave up on it a long time ago. I don't even have it on vinyl or CD.

Wow, the soundstage was jaw dropping, 3 dimensional, the sound was coming from places well above and away from the speakers it seemed. This was mesmerizing. What a great album, not sure I'll get it on vinyl, but I'll remember this listening session with it for some time.

I'll have to put some more hours on that new stylus, but I'm really digging this setup.

Now...what do I do for a turntable for the main rig upstairs? I don't want to think about it, not yet anyhow.

 

I had one in my system for a short time years ago, it didn't match well with my other components...was very thin and sterile sounding compared to my McCormack amp. But I know they sold a lot of them, so they must match well to some equipment!

 

Steve, did you ever use the later designed (MOSFET) bigger Adcoms, like a 5500, 5800, 5802?

 

Adcom always seemed like an audio "gateway drug". Beginner gear for high end audio. Something you used while you saved your money for the real stuff.

It was also the only equipment that was actually affordable in high end stereo shops back in the 80's!

 

I had a mk1 555 amp/pre-amp combo paired with Vandersteen 2cis back in the day, and while I can't say I remember the exact sonic signature, it certainly played louder than one would ever need. My brother has the amps now and still uses them (with Bose 901s!) although after 25+ years I'd think they might need a little tune-up.

I too had no idea Adcom was still in business.

 

This thread is going to make me donate my Adcom GFA555II to my nephew, and move up. Screw it.

 

That's a pretty sad statement. You hang your sonic beliefs on a thread other than your ears?

For every negative review there's a heck of a lot more positive reviews.

Again, it's a fussy amp though, when the synergy is there, wow.....3 dimensional sound with fast, tight, astounding bass is the norm. If you're not hearing that, well..... it's not working in your system. Don't believe me or the negative comments, trust your ears.


A fairly exhaustive test/comparison of it's sound FWIW....but I guess he's wrong because he's not on this forum, eh?

"Adcom GFA-555 power amplifier
By Anthony H. Cordesman Various • Posted: Apr 5, 1995 • Published: Apr 6, 1985
I am reluctant to call any given transistor power amplifier a "best buy" or "breakthrough." From my talks with designers and other audiophiles, it is clear that the state of the art in power amplifiers is about to change. From where I stand, the Adcom GFA-555 is the first sample of this new wave. It is so clearly superior to past amplifiers in the low- to mid-priced range—not to mention most amplifiers two to three times its pric—that I can unhesitatingly recommend it for even the most demanding high end system.

The GFA-555 does everything well, and most things exceptionally well. It provides superb, well-controlled bass with far better speaker load tolerance than most amps. Its midrange and treble are remarkably low in coloration. There is no hint of hardness, and none of the loss of inner detail common to transistor amplifiers.
With the exception of the Krells, I have never heard a more detailed, natural, and extended upper four octaves in a transistor amp. The Adcom may even be a legitimate rival to the Krell; it's brighter and more dynamic; and somewhat more open. And, like the Krell, it gives the impression, on really good material, that the amplifier simply isn't there. Nor is the Adcom romantic or sweet, like New York Audio's new Moscodes. Rather, it offers natural upper-octave detail that the latter miss. Other amplifiers have similar upper-octave performance, but I unhesitatingly recommend the Mcom over the very stiff competition from Tandberg and Threshold.
The Adcom's soundstage is sufficiently superior that even those who claim all power amplifiers sound alike might hear the difference. It comes very close to the better tube power amplifiers in providing detailed, stable, realistic imaging with natural depth. It is not an Audio Research D-250, but is extraordinarily holographic—I suspect almost embarrassingly so. This kind of soundstage has previously cost at least $2000.
I am also highly impressed with this amplifier's dynamics. Once again, it is not going to survive a one-on-one with the Audio Research D-250 or Conrad-Johnson Premier Fives, but it rivals any transistor power amplifier in its power class that I have heard—including high-powered receivers or amps with trick power supplies—at any price. It provides these dynamics into virtually any load without bloat, restriction of sound, or change in timbre. For all the nonsense published by most manufacturers about driving complex loads, this amplifier actually delivers.
The Adcom does not lose sweetness and detail as its power goes up. I am normally leery of transistor amplifiers rated much above 100 watts; they too often blur detail and harmonic information, and this sonic price tag is far more costly than the added power is worth. This does not happen with the Adcom unless the distortion lights are blinking, and they only blink when the amp is delivering well over its rated 200 watts per channel (8 ohms) or 325 watts (4 ohms). By comparison, once-outstanding high power amplifiers like the Hafler DH-500 now sound annoyingly veiled.
With a minor dealer modification, you can even drive 1 ohm loads like the Scintilla. I can't measure whether the Adcom delivers its rated 800 watts per channel into 2 ohms, or 20 amps peak, but I can tell you that it does a superb job of driving this superb speaker. Anything in its price range (or even close) generally changes timbre and degenerates when driving the Scintilla at 1 ohm.
I'm going to have to say a few words about its technology before I give Adcom a swelled head. You'll be happy to note that the manufacturer claims for the GFA-555 a simple gain path, a 700VA toroidal transformer, a well-regulated high current power supply, new ultra-stable bias circuitry, direct coupling, no current limiting, and no output inductor. More substantively, its harmonic shape mixes suitable yinyang while avoiding the curse of pyramidology. This, of course, means that it weighs 34 pounds, has simple rack-mount black styling, pilot lights, warning lights (to indicate distortion levels above 1%), and measures exactly 7 5/16" by 12¼" by 19".
More pragmatically, the technical specifications are significant in that they represent reasonable bandwidth (4Hz-150kHz), damping factor (150-200), gain (27dB), and noise (-106 dB). Of these only the noise specification is outstanding. No attempt is made to beat distortion records: 0.09% THD at rated power into 8 ohms, and 0.25% into 4. I have heard so many power amplifiers with infinitely (well, an order of magnitude) better specifications sound so much worse; this may be the amplifier whose sound could convince Stereo Review, High Fidelity, etc. that their present measurements are virtually worthless.
I suspect that the Adcom is going to force many designers in the $1000-$1500 range to either make radical improvements in their products over the next six months, or look at the possibility of retiring from competition. This is a "must" amplifier to audition before you spring for anything close in price. If the Adcom is simply the first of a whole wave of good amplifiers, it will help revitalize the high end for the average audiophile, and force most manufacturers into more reasonable pricing. Anthony H. Cordesman"



Just because someone who's word "seems" to hold some weight says it sucks does not mean a thing. Opinions are like you know what, and everyone has one. And............Just because it's working fantastic in my system means nothing either.

Listen and figure out how it works or does not work in your set up.

It is sad though that some folks like to toss out their negative blanket statements. I'm glad I trust MY own ears and not someone talking in unproven, nonfactual absolutes. 99.9999% of the audio hardware out there sucks according to someone at some time or other.

 

Heh - my old man still has a 555 preamp / 555 amplifier combo that get daily use. They used to power some Genesis speakers with ribbon tweeters but the foam rotted out on those. Now - his interest in stereo gear was never that high and his hearing isn't what it used to be - it is a pair of cheap Pioneer FS-52 tower speakers.

 

My Adcom 545II amp & 565 pre-amp make me happy. Don't care how old/dated/uncool/mid-fi/cheap/etc they may be... or what y'all think!

 

I had an Adcom 555 driving Vandersteen 2c's as my first high end system. It was a great match. Sounded terrific.

 

This was the case for me. I had several of these, 2- 555lls, 535ll, 2535ll they were cheap and didn't know any better.

This is where mine ended up and I still use them. I think it makes a great subwoofer amp mine are flat to 16Hz.