Axiom Home Page Forums General Discussion Stereo The Audiobytes are here!

John,

We're waiting with bated breath for your review of this amp. I am particularly curious to hear if the half watt coming out of it is better than the half watt coming out of an integrated receiver .

But kidding aside, at lower volume levels is there a discernible difference in sound quality?

This is true...I have been close to ordering the BPA-1 from emotiva for the crazy price of $129...however, I really think that Axiom has awesome QC and I am willing to wait for a product from them that I can use in my studio. Plus Axiom's amp is 120 watts/channel. Amie said a november release was looking likely, but judging by past product estimates by Axiom, I expect the amp in December now.

The bookshelf amp will be powering some studio monitors (M3s or M22s)

Most of the time at reasonable listening levels you are only going to need a few watts 1-10 say to drive a speaker. But that is not why you need a robust amp. Ever hear a sudden orchestra crescendo where the instruments are indistinguishable? Or a cymbal clash that hurts your ear? Or a kick drum that sounds limp? Like most people you probably turn the volume down to get it to sound better or someone yells its too loud. That messed up sound is what a clipping or distorting amp sounds like.

If you have ever watched an amp with metres you can see how they rock upward when loud transients suddenly demand tenfold or more watts . When demand exceeds supply nasty stuff happens like intermodulation and harmonic distortion or fried voicecoils.

How much power you need depends on your speakers and listening levels but it would be a mistake to suggest that the dynamics of any speaker would not be improved by using a more capable amplifier.

Regarding receivers, I'm a big fan of receivers because of their excellent feature set but a receiver does compromise fidelity compared to separates because of the presence of a large transformer in a metal box near circuitboards, wiring and transistors. Great care must be taken to minimize problems such as heat dissipiation and RF interference which is always there to some degree. Separating the amp from the pre-amp virtually eliminates those problems.

So yeah a half watt from a separate amp will usually b e better that from a receiver for many reasons.

This is what I don't understand, John.

If I am listening at 1W/channel nominal, I still have about 20dB of headroom left with my 90W/channel amp. I've measured 88dB in my room at 1W/channel...so it's a comfortably loud SPL. Why would I ever want more?

Now I admit, as I've said before, those who listen to orchestras are in a completely different league. In order for me to appreciate classical and the like, I need to turn my gain wayyyyy up!. If I listened to this kind of stuff on a regular basis, I wouldn't think twice about buying an A1400. I don't know how JohnK can live without one. Unless of course he's just listening to it at a very low level as background music. But when I listen to music, I want to enjoy it and hence I've been known to turn it up from an eighth of a watt to a half watt .

I'm not sure about your point regarding heat and RF interference. After all, there's heat and RF interference in a power amp although by the time the signal hits the power amp it is greater in magnitude and therefore the signal to noise ratio is much greater. But all of these integrated receivers have S/N ratios that are ridiculously high...much higher than the theoretical 30dB limit of human hearing...and extremely low THD+N figures.

You want more power if you want to experience full dynamic range without clipping. What you are not appreciating perhaps is that any music, jazz or rock included, or movie soundtrack with wide dynamic range will require sudden short large swings in power ten to 100x times more than what you are coasting along with most of the time. Most people don't realize that their amps are clipping and distorting albeit only briefly. Basically if you want cleaner unclipped sound you need more power on reserve.

Another classical loving friend of mine uses a 40w 2 channel amp to drive large Meadowlark floorstanders. I've gotten used to him running up to turn down the volume during climatic passages. He says he prefers it lower and I haven't mustered the courage to tell him its because that amp clips too often with those large speakers at any higher listening level.


From a psycho-acoustic perspective, the distorted sound from a clipping amp is perceived to be loud. Let me give you an example regarding one of my brothers, who visits from L.A. every few months. He annoys my wife in that he keeps raising the volume on my gear way over what I would because it doesn't sound "loud" to him ie. distorted. I know that he uses an older HK 5 ch receiver with a "rated" 80wpc which whenever I hear it I have to turn down too because its butchering loud transients which I find irritating and sounds "louder" though it is not.

The point on the RF and heat is that its outside of the box and cannot influence the processing circuitry. The pre-amp processes the signal at low voltage which is more easily corrupted in the same box as a large transformer. The better receivers minimize the problem but can't eliminate it, unlike separating the amp from the processer.

Also remember that S/N ratios are only part of the picture and need to be referenced to something to be meaningful. Many manufacturers quote them at 1 watt which may be much different at another wattage or full power. Some of the numbers including rated power thrown around by several well known receiver companies have been shown to be very misleading over the years.

Oh I'm well aware that any kind of music can have large dynamic range but I have only found this to be an issue during classical and orchestral. I'd like all music to have natural dynamic range rather than be compressed even if it means I have to buy an A1400.

I would argue however that above a couple of hundred watts, the majority of speakers out there start compressing. So everyone with M80s is "power-proofed" .

I don't understand why Axiom isn't exploiting all of the points you made. Maybe they don't have to in this market. I'm just surprised there isn't more evangelizing going on.

I'm giving the a1400-8 a good listening over several weeks. It really impressed me recently with an old track by jazz/classical trumpet player Wynton Marsalis "Napoli, Variations on a Neapolitan Song" from Carnival. Its a trumpet accompanying a wind ensemble so its full of quiet passages and searing high pitched trumpet solos. You want dynamic range, well that one has it so its a real test for how well the amp can start and stop and respond to fast demands for power. I've heard that tune many times and the natural crispness of the cymbals, brass and trumpet with the Axiom amp really surprised me.

And what kind of levels were you listening at?

Out of curiosity (A1400-8 is in my mid-term plans), what was your amp before? Because the mid-term could before January if I feel the need...

Eric,

I know that you listen to classical and orchestral to a great extent. I really don't know how you can do so effectively with the modest power of your receiver.

I have listened to numerous pieces suggested by JohnK and I find that I have to turn my Denon up to -2 which is a nominal of 50W/channel in order to hear quiet passages...and even at this level I would say I am not satisfied. This of course leaves me no headroom to speak of with my meager 90W. Now you probably have more like 150 clean watts out of your Onkyo but this represents less than 5dB of headroom. You really are no better off than me.

You and JohnK are great candidates for the A1400. JohnK however is limited by his M22s...but you're not .