Adcom GFA-555ms Power Amplifier Reviewed

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Adcom was once one of the most dangerous audiophile creatures on the planet back when the dinosaurs roamed the Earth—when sporting a Sony Walkman was quite stylish. This era predates my audiophile journey by about a decade, but I have some fond-yet-fuzzy memories of seeing Adcom stock displayed proudly on the shelves of early-1990s hi-fi and electronics shops. Adcom was proudly sold in every good audiophile retailer and regional chain in an era when there wasn’t an almighty Internet to tempt you in a million different directions while shopping for audio gear. The company ran double truck ads (that’s publishing talk that means two pages together) in every respected audiophile print magazine, as their reviewers ogled over the company’s mix of value and performance—and rightfully so. Then, abruptly, Adcom went away, as if an unexpected audiophile asteroid wiped them off the planet. 

Now, it is almost 2024, and believe it or not, Adcom is back in the audiophile game. 

Adcom GFA-555ms is the latest version of the legendary Nelson Pass designed amp priced at $1,395 today
Adcom GFA-555ms is the latest version of the legendary Nelson Pass designed amp priced at $1,395 today

Seriously, they are back—and while the brand is seriously evolving, Adcom is not ignoring the success of its legacy products, which earned the admiration of the audiophile world in the first place. The company offers a modest audiophile integrated amp, as well as a simple stereo preamp called the ADCOM GFP-915 for $999 (read the review), but the topic of this review is the legendary, Nelson Pass-designed GFA-555ms power amplifier. 

Priced at $1,395 (seemingly pretty accurately adjusted for inflation), this is still a value-priced, traditional class-AB audiophile-grade amplifier. The GFA-555’s ability to drive difficult loads is still relevant today in a world recently filled with new-school, class-D amps that are very exciting. The Adcom GFA-555ms is a “great fucking amp” (that’s what GFA stands for, in case you weren’t in on the joke back in the day) that packs 125 watts into 8 ohms and 200 watts into 4 ohms. Its bigger brother, the $1,895 GFA-565, features even more pure power, assuming that you need it.  But with the excellence in today’s speaker design, 125 watts into 8 ohms is pretty stout. 

The GFA-555ms isn’t very heavy at 26 pounds, nor does it create a lot of heat like a tube amp or a pure class-A design. You can also bridge a pair of Adcom GFA-555ms amps for 400 watts per channel, creating a very reasonable upgrade path for audiophiles who are looking to build a reserve of amplification that could drive any speaker in the market today as well as nearly every legacy speaker from the past. 

There might be no one audiophile amplifier that passes the test of time better than the ADCOM GFA-555 now in its "ms" version
There might be no one audiophile amplifier that passes the test of time better than the ADCOM GFA-555 now in its “ms” version

What Makes the Adcom GFA-555 Power Amplifier So Special? 

  • If you want a Nelson Pass-designed power amplifier from Pass Labs, the entry level is $5,125 for the XA25, which is a 25-watt, class-A amp. While the XA25 doesn’t have a sexy gauge on the front face like its more expensive cousins, it puts out a sweet 25 watts (enough for nearly all of our listening, believe it or not) of class-A power. It also draws a ton of power from the wall and creates a ridiculous amount of heat while costing about 400 percent more. The Adcom GFA-555ms is not class-A, nor does it have that sound, but it is a low-cost way to get a time-tested amp designed by perhaps the greatest amp designer ever for a mere $1,395.
  • You can drive nearly any speaker on the market today with an Adcom GFA-555ms. When Adcom was the king of the electronics value game, there were some notably hard-to-drive speakers on the market. MartinLogan CLS (non-hybrid) electrostatic speakers come to mind. Ultra-tall Acoustat electrostatics were also notably brutally tough to drive. Comparatively, and generally speaking, today’s speakers are so much easier to drive compared the majority of high-end speakers during Adcom’s early days. With that said, the GFA-555ms had (and still has) the power and the current to get the job done. 
  • The GFA-555ms doesn’t have a strong sonic signature XA25and that’s a good thing. Some audiophiles want a sonic flavor from their electronics (think: tube lovers) but I tend to desire a neutral and natural reproduction of my favorite music. The GFA-555ms achieves this. 
  • The GFA-555ms is built to last, and this is absolutely proven over time. People still buy vintage GFA-555s amps on eBay even with 30 years of daily use on the odometer. At $1,395 today, you get that new-amp smell from a legendary audiophile brand that has no mileage and is ready to rock. 
  • As mentioned in my opening, I like the upgrade path that allows one to add a second GFA-555ms in bridged mode to get to 400 watts into 8 ohms.

Why Should You Care About the Adcom GFA-555ms Power Amplifier?

There are many just-add-speakers audiophile products on the market today. They come complete with an audiophile end-point for streaming, a modern 24- to 36-bit upscaling DAC as well as a preamp and an amp—all in one chassis. Don’t get me wrong—these all-in-one component solutions are great, but there’s something reassuring about having your audiophile investment in separate electronics, including a rock-solid power amp. You’ve got a better upgrade path for the future, dedicated power supplies in each component, and, well, separates just look cooler. The GFA-555ms delivers on all these fronts. 

There are far fancier and more polished-looking amp brands on the market today, but few with the track record, design pedigree, and low cost of entry that the GFA-555ms offers today’s audiophile. 

A rear view of the ADCOM GFA-555ms audiophile power amp
A rear view of the ADCOM GFA-555ms audiophile power amp

Some Things You Might Not Like About the Adcom GFA-555ms Power Amplifier

  • The industrial design of the GFA-555ms hasn’t changed in 30 plus years, and while I love the throwback design, some might consider it a little dated. There are also no options in silver, which many audiophiles prefer over basic black. There are no Vinnie Rossi-looking meters to watch as you listen to Steely Dan. The Adcom GFA-555ms is a pretty basic looking amplifier as it hasn’t gotten a facelift for the modern era. 
  • At this price point, there are new-school amplifier technologies in the market today that demand consideration. There is no Gallium Nitride semiconductor in the Adcom GFA-555ms. There is no Hypex chip technology either. Pascal chip? That’s not part of the design. This is a well-made, traditional class-AB amplifier design—not one of these new school class-D amps that are making waves in today’s market. 
  • The GFA-555ms isn’t super light. It won’t give you a hernia lifting it like a Gryphon or Boulder reference-grade power amp, but it’s still hefty. 
  • Heat isn’t a major concern, but the Adcom GFA-555ms doesn’t ice-cool-to-the-touch while blasting out Rob Zombie songs at 110 dB like today’s new school, class-D amps.
  • The GFA-555ms won’t shatter your electric bill like a class-A amp, but it still uses more power from the wall than many of the new players in the space. More so than ever, modern audiophiles consider power consumption and environmental friendliness when assembling a system. You can by all means leave the GFA-555ms on all of the time, but by no means do you have to, nor does a warmed up amp physically create better sound. That’s an audiophile wives’ tale that won’t die easily, sadly. 

Listening to the Adcom GFA-555ms Power Amp… 

I powered my SVS Prime Pinnacle Floorstanding Speakers with the GFA-555ms fed by an Adcom GFP-915 preamp.  All music was streamed through Qobuz at max settings and connected directly through my Asus ROG Zephyrus G14 laptop. 

I couldn’t help but look at the GFA-555ms and feel nostalgic. Everything-from the bright red Adcom logo to the chunky power switch oozed 1990’s aesthetic and design, à la my early 2000s PlayStation 2, which I bought after saving up several paychecks working at my neighborhood pizza shop. I spent endless hours gaming and listening to CDs on this beloved console, and the GFA-555ms would have been right at home sitting next to it in my teenage bedroom audio system. 

Fittingly, I chose “Jellybelly” from The Smashing Pumpkins mid-90s opus Melancholy & The Infinite Sadness – Remastered 2012 (Qobuz, 16-bit/44kHz. This is a ridiculous song off a ridiculous album that I loved then and still love today. That said, it deserves an amp that has the straightforward power and grunt to push my loudspeakers without fatigue. The GFA-555ms did a fantastic job, allowing James Iha’s thrashy guitar to stand out while also fleshing out the crunch and sizzle of the rest of the arrangement. Billy Corgan’s vocals were crystal clear, and the dynamic shifts throughout the track remained fun, fluid, and full of depth. I am by no means an amplifier aficionado, so I decided to A/B compare this amp to my tiny-but-mighty PS Audio Sprout100. The most noticeable difference for me, specifically within this track, was the fullness and dynamic range the Adcom provided. The GFA-555ms sounded fuller and bigger overall. And while the Sprout is incredibly clean, it plays a bit more intimately.  And as a bonus, as I increased the volume on this track, the GFA-555ms somehow sounded better and better, showing off its ability to competently handle music at higher volumes. It almost seemed to crave it. 

Smashing Pumpkins on

It’s one thing to be able to play loud and proud, but what about finesse and emotion? Max Richter’s “On the Nature of Daylight” off the album The Blue Notebooks (Qobuz, 24-bit, 192 kHz) is the type of arrangement that will cause your life to flash before your eyes, which is likely why it has been used in a variety of cinematic contexts. This is a track that builds and builds, which can be a torture test for amps and receivers with a tendency to crack under pressure when the going gets tough. The Adcom GFA-555ms not only kept up with the layered crescendos and building tension within this beautiful song, but it did so with authority and incredible warmth. At the first major crescendo, the featured violin solo came to life; the song widened as the amplitude increased, which gave the illusion of a concert hall experience. I can honestly say I did not expect this level of detail, soundstage, and overall emotive capability from an old-school amp, but the GFA-555ms continued to remind me why it’s important to never judge an amp by its cover. 

Max Richter’s “On the Nature of Daylight” off the album The Blue Notebooks

Will the Adcom GFA-555ms Hold Its Value?

If past performance is any indicator of future performance (unlike most of the mutual funds in my 401k) then expect the GFA-555ms to hold its value fantastically well. Today, on eBay, vintage used Adcom GFA-555s sell for their original ‘90s retail price of about $600. Why wouldn’t a new Adcom GFA-555 hold its value, as well? It likely will; moreover, the cost to get in the game with a GFA-555ms isn’t very high, so the amp doesn’t have a ton of value to lose.   Also factor in the upgrade path to bridged GFA-555s and there is a built-in audience looking to add a second amp for a bigger reserve of power. Basically, there is somebody looking to buy one of these amps even if you’ve moved on to something higher up the food chain, so I would say there is little to no risk in the value department of the  GFA-555ms. 

Who is the Competition for the Adcom GFA-555ms?

Monoprice’s $1,099 2×200 watt Monolith by Monoprice M2100X amp (read the review) is rumored to be designed by ATI’s Morris Kesslerthus a secret weapon in many a budget audiophile’s arsenal. The direct-to-the-customer model at Monoprice is part of their value, but borrowing a move from Adcom, the company often covertly employs rockstar designers, elevating its products and providing excellent value. The Monoprice isn’t a pretty amp by any means, but it sounds good and comes with a great amount of power for a little less cash than a GFA-555ms.

Back in the day, the Aragon 4004 was the next logical choice for audiophiles seeking a serious amplifier with killer pedigree above where Adcom was normally priced. The founder of Krell, Dan D’Agostino, designed the Aragon amp back in the day, and it was known for its distinctive V-shaped chassis as well as having Krell-like bass control. After having its fair share of turmoil over the years, Aragon was sold by Indy Audio Labs. Today, the version of the 4004 is called the Aragon Titanium, which is a 200-watt-per-channel class A/B stereo amp priced at $4,899. It is unclear (and unlikely) that there is much of D’Agostino’s design work still in this amp, and it clearly is now not just a few hundred dollars more than an Adcom GFA-555.

The Orchard Audio Duo ($1,349 per pair) is a GaN amp that brings all of the advantages of today’s new class-D power to an audiophile system at about the same price as the Adcom GFA-555ms. These amps are small, light, and create close to zero heat. They lack a specific sonic signature, per se, but can, like the Adcom GFA-555ms, power some tough-to-drive speakers. The metalwork is a little rough around the edges, but the power that comes from within is serious, on top of being a great value. 

Buckeye Amps NCx500 Amplifier, priced at $1,095, brings more power than all others in the space thanks to a Hypex module that makes it yet another new-school contender. These class-D companies might not have the historical significance of Adcom, but they deliver in spades when it comes to value. Fellow reviewer Mike Prager has this amp in for review and is saying very positive things about it. 

A close up photo of the rear of the ADCOM GFA-555ms power amp
A close up photo of the rear of the ADCOM GFA-555ms power amp

Final Thoughts on the Adcom GFA-555ms Power Amp

The GFA-555ms, while unassuming, packs incredible value and time-tested technology and quality into its retro-tastic design. The amplifier provides incredible soundstage, dynamic capability, handles high volume with ease, and can power even the most demanding speakers around, all for roughly half the price of many competitors. 

All too often these days, we are wooed by the latest/greatest/shiniest object in the room, which inevitably causes us to look past brands and products that overperform and overdeliver for less, minus the hype. Sure, change can be good, and there are new technologies on the horizon that will undoubtedly change the audiophile amplifier landscape for decades to come. But some recipes don’t need changing. 

The Adcom GFA-555ms is an excellent choice for the audiophile hoping to capture the essence of the hobby without wasting a penny on unnecessary features, gimmicks, or add-ons. It’s a big, black, bold building-block amp made by a legacy brand that has been thankfully reborn. I’m excited to see where the company takes things from here—just don’t change the GFA-555ms, please. It’s just fine the way it is for as long as you want to sell it to willing, happy audiophile customers. 

For information on ADCOM contact…
J&B Distributors Inc.

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Reuben M Edwards

Yes I still got my GFA 555 ii

Jerry Del Colliano

We did a little research on the old ones and they sell for retail value 30 years later. THATS AMAZING!!!


Very nice review. I own the GFA555se
(which you have pictured in your review) and I agree you can’t go wrong with the new Adcom amps. A touch of high end at a fraction of the cost.

Jerry Del Colliano

I agree that these amps are a GREAT and time tested value in the market today.

A true classic.


I own a first generation 555 from 1985. It is the only power amplifier I have ever had. The only repair I have done to it was recap it about 10 years ago. Still running great with Acoustat speakers that I’ve had since the mid 90s and have no intentions of getting rid of it.

Jerry Del Colliano

Acustats are BRUTAL to drive. Just Brutal.

Haffler was the classic solution back in the day but your 555 seems to do the job.

Thank you for sharing!

Steven Medel

To take what Joel stated, a little further. The pictures of the rear of the amp are incorrect. The pictures shown in this review, are the back of the Adcom GFA-555SE, which has balanced inputs as well as RCA. The Adocm GFA-555MS which is being reviewed here, does not have balanced inputs. Only RCA inputs. The price for the GFA-555SE is $1699.00 for those that need a balanced input.

Last edited 6 months ago by Steven Medel
Jerry Del Colliano

I am checking on this image issue.

I am helping Boris get with my audiophile photographer friend and teaching him how to get his photos organized on a site like the BIG PR firms do. That’s not ready yet but we want to get the details right.

Richard J

I have a decades old Adcom 545 (Nelson Pass designed MOSFET 100W/Ch) that has powered my Magnepans, KEF LS-50, Custom-built towers, and currently drives my subwoofer array in my theater. I couldn’t give it higher ratings. Bulletproof, durable and excellent SQ. I have a pair of 535s (same lineage, 60W/Ch) in storage for whatever.

All that said, I really glad to see Adcom back in the game. I can’t imagine anyone being seriously disappointed in their new offering.

Jerry Del Colliano


What a great value for you!


Had the 555 back in the mid 80’s. I had to sell it for personal reasons. Today I am happy with what I own and have no plan on changing a thing. This should be a reliable good sounding buy in today’s market. It is an amplifier while listening you realize cosmetics are not an issue.

Jerry Del Colliano

If the amp you have is good enough for you – then cool.

Today’s Class-D amps are simply EXCELLENT and SUPER AFFORDABLE when the time for a new amp comes around.

Who knows when you will get the bug for a new amp.


Richard Wallace

I own an old Adcom GFA 555 from the late 1980s. It’s still doing great!

Jerry Del Colliano


Mark Block

The Monoprice amp seems to have gone up in price. Also, I can’t find a 24/192 version of the Max Richter track on Qobuz.

Ken Duff

Hi, I am driving a pair of Martin Logan Prodigy Hybrid Electrostatics with a B&K Systems 200/200 watt power amp. I feel that my current B&K amplifier is not handling the high frequency impedance fluxuations very well. I am considering a pair of the Adcom GFA 555ms in bridged mode to replace it.
The above wrap up comments do not mention the speakers used in the review process. Has this amplifier been tested using the ML Prodigy speakers?
What feature or characteristic would you attribute to this unit being a suitable alternative to what I am using now?
Thank you for your reply.

Last edited 3 months ago by Ken Duff
Jerry Del Colliano

A million years ago when I was at Cello (early to mid-1990s) we sold both MartinLogan AND ADCOM and often those got paired together.

I didn’t know Bowers & Wilkins made an amp. I’ve been to their Boston (two owners ago) facility but they had mostly Classe stuff.

I think you will be fine with ADCOM. I can talk to Boris (the guy bringing ADCOM back) about giving you the chance to upgrade to 565s if you wanted. Email me if you would like my help…

Ken Duff

My current amplifier is a B&K Components Reference 4420.
Sorry if I confused the situation.

Ken Duff

Thank you for the very fast reply and I await any information you can provide.
Side note, I have been looking at the Sanders Sound amplifier. They have purpose built it to drive electrostatics.

Ken Duff

The downside to the Sanders Sound amplifiers is the expense. If two bridge Adcom GFA 555ms would provide the same performance that would be much better money spent.

Ken Duff

BTW, I have two home built transmission line subs using 18″ drivers, paralleled. I drive them with a rebuilt Adcom GFA 555II in bridged mode. Delivering 800 watts+. Where the Martin Logans taper off they are just gettin started!

Last edited 3 months ago by Ken Duff
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