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AM Audio A 50 Reference - class A power amp

You've come a long way, baby...

[Italian version]

Product: AM Audio A50 Reference - 50 watt class A power amp
Manufacturer: AM Audio - Italy
AM Audio - C.so Milano 102 Vigevano (PV)
Phone. ++39 381-347161 - Fax. ++39 381-346469
Approx. price (in Italy): 2,500 Euro/ 2,500 US $

[AM Audio A 50 Ref]
AM Audio A 50 Reference

Hey, what's up? Weren't Italians famous for fine and delicate tube amps and wood handcrafted loudspeakers? Sure, but not only: introducing you the AM Audio A50 Reference power amplifier.
AM Audio is certainly one of the best known HiFi Companies in Italy, at least among solid state fanatics. This Company, located at Vigevano, in the cold North of Italy, has been making hi-end electronics for years and now they also make loudspeakers and, hear hear!, CD players (actually Teac VRDS 25 mods).
Anyway, as soon as you mention AM Audio any Italian audiophile worth his weight in silver cables will definitely shout: massive class A amplifiers!.
Yup! AM Audio makes some of the finest pure class A power amplifiers around: think, just to have an idea, at the best Krell or Mark Levinson amps.
Under test is a well-known best-seller: the A 50, now available as a "Reference" edition. This classic 50 watts pure class A power amp has been around for years: firstly as a simple A 50, then as mkII, now as "Reference".
Not just a marketing move, this A 50 Reference is a very different beast from his predecessor A 50 mkII: total negative feedback has been eliminated and the signal path has been made as short as possible, thanks to a completely new layout of the circuits.
As you may argue from the pictures here, the A 50 Reference is a MASSIVE 50 watts real dual mono power amplifier: 40 kgs (approx. 90 lbs!) of toroidal transformers, larger than life capacitors (see the golden pillars in the pictures) and output devices.
It is able to deliver 50 amperes (peak) of current to your loudspeakers while continuous power rating is claimed to be 50 watts @ 8 Ohms (all in Pure class A).
Because of the Pure class A operating condition, everything needs to be overbuilt and oversized: if you have never experienced how much heat can produce a REAL class A unit...well, I guess you are wondering why both sides of this amp are entirely covered with massive heat sinks....Hey, I told you Vigevano is located in the COLD North of Italy...
Joe, this is probably the biggest and heaviest 50 watts power amp in the market!

You've come a long way, baby (Fatboy Slim)

[A50 Reference inside]
Sexy inside view: no top cover, thanks!

If you are a tube nut, a die-hard triode maniac...well you should test drive this amp, probably you'll discover that not all big solid state amps were created equal.
This A 50 Reference is very, very refined and utterly transparent, despite its looks can make think at a brutal, rude, louder-than-life performer.
Don't let the looks fool you! This power amp is so delicate that you immediately forget you're actually listening to such an obtrusive and heavy beast.
With respect to its tonal balance, I'd say it is extremely neutral, perhaps a bit on the "clear" side (as opposite to "dark") though definitely not bright. Its sound is grainless, introspective, detailed and elegant as one would expect from any hi-end tube amplifier worth its weight in vacuum tubes...but this is solid state, dudes and dudettes!
And you realize this as soon as the mid-bass and the bass range require some extra "kick" and "drive": the amount of energy this amp makes flow through your cables is outstanding, especially if you consider it is, after all, just a mere 50 watts amp.
The bass range is deep till its lowest end, powerful and floor-shaking. Take some electric bass recording and you'll experience the careless whisper of this beast: the bass notes will make your chest resonate, literally! Don't think it is the kind of "overinflated" bass you sometimes can hear from small audiohile integrated amps...NOPE! This is a clean, neutral and tight bass range, aggressive only when needed.
You won't find nothing particularly "spectacular" in the performance of this amp: its inner neutrality and control will let the Music flow through it effortlessly, no frequency range being particularly "ahead" of the rest. Coherent, precise and transparent...with plenty of good bass.

Micro & macro dynamics

[A50 Reference, rear view]
Hi-quality connectors in the rear

What would you expect from a solid state power amp with a 50 amperes claimed current output? You bet! PLENTY OF PUNCH and lively dynamics, ready to give the needed energy to your favourite crescendo's and fortissimo's. Give in, not give up!!! seems to be the A 50 Reference own credo and so you (and your friendly neighbourhoods) will experience listening to those symphonic pieces at levels louder than usual.
No, it won't make your walls shake but you'll be able to hear the Music with your body instead (chest and feet, via the floor...). It never shouts, even when the terrible finale of the Berlioz's Sinfonia Fantastica (Ref. Rec. edition) seems a neverending explosion, where many amps simply GIVE UP way before the end.
Just to make things clearer, at the risk of being trivial, forget those audiophile 50 watts amps, because this is an entirely new experience: it is not a matter of POWER...rather it is the amount of pure energy your amp can trasmit to your loudspeakers.
But don't get me wrong, the A 50 Reference is plenty of savoir faire and never appears to be rude or brutal. Conversely, if a fault has to be investigated, I'd say it lacks a bit of the brutality and pure violence needed for some rock recordings, for example. If it was a car it would be a big high-torque sedan instead of a nervous Corvette or Lamborghini.
It sounds fast with a good sense of "pace" though it never gives the sensation of being always in the pursuit of the next note, if you know what I mean.
Thanks to its transparency, the tiny details and the minimal energy variations (microdynamics, that is) of the musical program are carefully respected and reproduced.


As I always say, anyone used to listen to smallish audiophile amps should experience, once in a lifetime, the BIG sound of a BIG amplifier: the soundstage created by the A 50 is large and stable, filling the whole space behind and between the loudspeakers and sometimes extending laterally way beyond the 'speakers.
Certainly one of the best "pluses" of this amp is its ability to maintain the same 3D scene even during complex and loud listening sessions: each perfomer remains in the same own place, the scene never collapses. When using good recordings the depth of the scene is several meters beyond the rear wall.
Being trasparent, this amps doesn't forgive poor soundstaging recordings: you'll be able to detect all the errors made by the sound engineer of the recording such as misplaced mics, uncontrolled echoes of the recording hall and so on. So, if an instrument or a voice has been recorded so to appear "small" the A 50 won't overinflate it (as some big amps often do...)

Some advice

Well, just a few. If you aren't used to deal with big and heavy HiFi components, consider having a friend to help you moving the A 50 reference into your listening room. Find a suitable, stable and solid place where to install it because it is HEAVY and needs plenty of fresh air around: do not forget this is a REAL pure class A amplifier and it gets EXTREMELY hot during operation (it is CE certified, though). You can even SEE the warm air flowing from the heatsinks...like hot air from asphalt during hot Mediterranean Summer afternoons.
If you live (like me) in a very warm climate please consider you may need a good air conditioning device into your listening room. Conversely, during winter, you may save hundreds of your hard-earned $$$ because this amp works as a perfect heating device :-)
As for partners: the A 50 Reference is mostly neutral, so it is up to your taste to decide which CD player/preamp/cables or loudspeakers to use: you can be sure this amp won't "color" the sound of your system. Thanks to its driving capabilities, you can use ANY loudspeaker you want, literally!


I've already said it is heavy and unpleasant during Summer, you've been warned.
Anyway, thanks to its 4 handles (front and rear!) moving it around isn't all that difficult.
Plus, your kids can safely PLAY with it: impossible to destroy since it is built like a battleship, it has NO sharp edges, for this reason I'd rate the home-friendliness as very high.
And now the sound: if you're looking for a "personal" intepreter, well, look elsewhere since this amp is mostly a wire with gain and nothing else. Some audiophiles will love it for this, others will prefer a more "coloured" kind of sound: up to you to decide, the choice of any HiFi component is very subjective, after all's being said and done.
As for me, I'd have preferred some extra "kick" with violent and aggressive rock Music but then one should consider this is a 50 watts amp, not a 100 or 200 watts per channel beast.
For this reason AM Audio makes some bigger brother, still in pure class A: the A 140 and the A 200, with the numbers being related to the output power per channel. And yes, Virginia, these amps are supposed to be really HUGE and HEAVY. For example, the A 200 weighs in a mere 150 lbs with an impressive 190 Amperes (yes: one-hundred-and-ninety) peak current output!!!
Also, I'd have preferred a more "involving and involved" reproduction: this is one frequent complaint some audiophiles make to neutral amps like the Mark Levinson stuff, for example. All being perfect, neutral, uncoloured and sometimes ...too much of a good thing.
This complaint has been made without any reference to the price of the unit. Actually, if one considers the 2,500$ figure for such a big and nicely built amp...he'd better keep his mouth shut :-)


It is very hard to find real competitors for this Italian power amp: how many dual-mono 50 watt pure class A amps are available today? Oh, let me add: at THIS price. The answer is easy: NONE.
There's an Italian competitor, the Audia Flight 50 power amp you may have seen browsing our Reportage from the 99 Top Audio Show but this costs 1,000 $ more so it is not a REAL competitor.

In other words, the A 50 Reference is very special amplifier, with a very high quality/price ratio, something one should seriously consider if a neutral, lively and detailed solid state power amp is needed.

A warm (as pure Class A) thanks you to Attilio Conti by AM Audio for having sent us this amp for reviewing.

© Copyright 1999 Lucio Cadeddu - http://www.tnt-audio.com

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