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Re: Reflections on the A1400-8 and other amps
Worfzara #188789 12/18/07 03:44 PM
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jakeman Offline OP
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With music it was more apparent at moderate to high volumes. With HT I found it harder to discern but on loud passages the difference was apparent as well. For HT I keep the Arcam at around 80db.

A problem with my Outlaw 770 and many other amps is that a significant amount of the watts specified get lost as heat. Just about every amp I have known are just not as efficient as the A1400-8. I remember reading some time ago at the Audioholics forums that the 770 is only 40% efficient or 60% of the energy gets dissipitated as heat. That means that of the 1800W they brag there really is only 720W ( 40% x 1800W) of available power or only 720W/7 = 103W per channel. There is no way it will output the spec'd 200W@ 8ohms into my speakers. Which means more clipping at peaks during intense movie scenes or in concert DVDs.

I'm not knocking Outlaw just pointing out a big problem with interpreting the power numbers thrown around by many amp manufactuerers including or especially the ones in receivers. While the lab numbers are worth knowing, without knowing the efficiency of the amp its performance will not be as much as you think.

Now lets look at the A1400-A. Because of their brilliant engineering using only Class D, it is rated at 92% efficient though because of Axioms usually understated conservative approach I questioned it and they fessed up that the efficiency is more like 96% or 1344 available watts. With all 7 channels going under the same simulataneus load, and ignoring for now the Axiom amp's unique ability to route more power to whatever channel demands it, the A1400-8 has 192W available. Also note that if you run fewer channels there is even more power available per channel ie 267W for 5 channels while the Outlaw never changes from 102W. The Axiom amp will likely do more but its limited by the typical 15 amp house circuit.

Then their is the speed of the amps. The Axiom amp has far better slew rate and rise time. It also benefits from how the capacitors are arrayed with different sized caps while the Outlaw has 7 same sized 22,600 uF of capacitance per channel (158,200 uF total). Even though the total capacitance of the Axiom is slighly less at 140,000 uF because it has different sized caps it can respond faster to the input signal. That means more clearly defined transients and higher resolution sound.

The A1400-8 also benefits from uniquely designed silicone output transistors proprietary to Axiom. On this point, I have had better luck trying to acquire a key to Fort Knox.

Anyway, the Axiom amp is a big step up in performance compared to the Outlaw. Having said that the Outlaw its a respectable amp for the price.





John
Re: Reflections on the A1400-8 and other amps
jakeman #188793 12/18/07 03:56 PM
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For HT performance, do you have HD-DVD or Blue-Ray to see if that's the reason why the difference is harder to spot?


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Re: Reflections on the A1400-8 and other amps
EFalardeau #188794 12/18/07 03:58 PM
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jakeman Offline OP
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I use a toshiba HD-DVD XA2. It is audible like I said. However I can more easily spot problems when listening to music. Maybe I need to hear more explosions. ;\)


John
Re: Reflections on the A1400-8 and other amps
jakeman #188797 12/18/07 04:05 PM
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XA2... Cool! I have the mere A30 (I had a A20 prior, but it died).

Thanks for the info.


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Re: Reflections on the A1400-8 and other amps
jakeman #188800 12/18/07 04:21 PM
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Thanks John

I have tried many power amps between the $500 and $2000 range including Rotel, NAD, Outlaw, and some pro amps including Audio Trak and Inter-m. Some of these had standard transformers, some with upgraded toroidal transformers. To my ears they all sounded the same. The Rotel seemed to dissipate almost no heat, and the Audio Trak gets as hot as a George Forman Grill. But all sounded similar, if not identical, at least to my ears.

However, I have never listened to a class D amp before.


paul

Axiom M80, VP180, Qs8, EP500
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Rotel RB-880
Denon AVR-990
Re: Reflections on the A1400-8 and other amps
Worfzara #188805 12/18/07 04:53 PM
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I find the more powerful better designed amps generally use better materials and circuits. The difference is most obvious musicically in bass peaks and other transient reproduction of cymbal hits, piano notes, kick drum etc. Over the years I gravitated to the larger amps in the Bryston line for that reason.

One of my favourites was a 14BSST which I sold two years ago to a guy who was underpowering some Maggies 3.6 with a Classe amp. Instead I picked up the 4BSST pair. I can hear the difference between the single 4BSST and the Outlaw, and the A-1400-8 and one 4BSST but its a tossup between the pair of 4BSSTs and the A-1400-8. No surprise there since the a1400-8 got its inspiration from a pair of 7BSSTs.


John
Re: Reflections on the A1400-8 and other amps
jakeman #188830 12/18/07 07:05 PM
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Audiogon

Not trying to advertise this guy's sale but it seems a little weird to me to be selling this, plus he's in the UK. I wonder if Axiom has shipped any of these amps to the UK yet?


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Re: Reflections on the A1400-8 and other amps
Lorenzo1000 #188834 12/18/07 07:10 PM
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I didn't expect to see that this soon.

Interesting.


paul

Axiom M80, VP180, Qs8, EP500
Epson 3020
Rotel RB-880
Denon AVR-990
Re: Reflections on the A1400-8 and other amps
Lorenzo1000 #188835 12/18/07 07:16 PM
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"Ship from 28lbs from UK". If that's the weight, then this is a hoax (weight is 54lbs).


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Re: Reflections on the A1400-8 and other amps
EFalardeau #188840 12/18/07 07:47 PM
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I wonder if that 28lbs should be 28 Kilograms. Which would be 61 lbs, very close to 54 lbs of the actual unit.


paul

Axiom M80, VP180, Qs8, EP500
Epson 3020
Rotel RB-880
Denon AVR-990
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