Axiom Home Page Forums General Discussion Stereo Amplifier Question?

I was looking at the NAD C 275BEE approxmatley $1500 retail, Rotel RB-1572 @ $1500 or the Anthem MCA20 @ around $1100. Do any of these warrent the higher price tag in relation to preformance compared to the Outlaw M2200 which is $350 US each. Does outlaw make just a 2ch amp? I did not see one on their web site.

Thanks
Phil

It depends on who you ask.

2 M2200 is what you would be looking at from Outlaw. If you want 2 channel maybe looking at pro amps as a few here have done might interest you. Qsc Audio GX series

avaialble at Axe Music here in Alberta.

Phil, Nad and Rotel have been building amps for a very long time. they have many years of R&D. I own a Nad processor and love it, i did think about getting an outlaw when i bought my Nad, kind of similar situation you are in, the Nad was 1500$, and i think the outlaw processor was 900$ish? i demoed the Nad, and could tell a difference between the Nad and what i currently had at the time, so i was happy with the 1500$ that it cost. the shop also had Nad amps, and they sounded good, and were solidly built. In my opinion, Nad is where the law of deminishing returns starts to come into affect. With a Nad product you will get maximum performance for your dollar, if you go to some of the higher priced companies, you are not really getting a lot more performance, for the lot more money you are spending.


I would tell you to find a retailer in your area that sells Nad and Rotel, listen to their amps if you dont think they are worth the money right there. then buy the outlaw, they have the 30 return policy also right? if you receive the outlaw and YOU are happy with it, then keep it.

One thing you can try to do on your own Phil, is try to find out, how many transistors each amp has per channel, the more transistors the amp has the better it will hold up under a large load. If you can find out what kind of transistor each manufacture is using, you can find out more about the characteristics of the amp..

the power supply and transistors are at the heart of all solid state amps, some companies use overly built products, while others use products that will just do what they want.


I hope this helps you some, Alex

Phil, the 2200 is a monoblock, so you would get one for each speaker you "think" needs one.

Also, based on your prices listed above, you might consider some offerings from the highly regarded ICE digital and Solid State Wyred4Sound Amps

I thought there was some particular problem with ICE amps, which is why Axiom elected not to use the design. Anyone know anything about this?

From what I've read, the ICE design back in the 80's/90's designed by B&O give the ICE a bad rap. Today's designs don't have any issues. D-Sonic is another options. Both W4S and D-Sonic are manufactured here in the States, not China.

Oh, I thought the B&O ICE design was the reference for the others. Shows what I know.

You tall, thin people.... always arguing....

I'm sure Axiom is going to downplay ICE, but many amp manufacturers are very reputable and have a large following.

So do tubes. <runs away>

Thanks for all the input maybe I will try to listen so some amps in Edmonton when I get there.

Phil, another Canadian source to look at for 'pro-amps' would be Acclaim Music.

Would these Yorkville ones be any good?

http://yorkville.com/products.asp?type=30&cat=8

Not too sure that I would want a pro amp in my HT rack. Would they work as well as a true stereo amp?

It depends who you ask...

Er... What would be the terminology difference between "pro amp" and "true stereo amp"?

The professional A/V people that I know and work with (ones who do commercial, churches, etc.) don't recommend pro amps for 2-channel or HT use, and don't use them in their own home systems. QSC, Crown, etc. is great gear, but pro equipment is made to be rugged and reliable, not to provide a very high level of sound quality. Very few commercial installations are designed to, or have the ability to, provide the kind of sound quality that we want in our homes, regardless of the electronics - too much ambient noise, questionable room acoustics, highly distributed seating/listening areas, etc. Good gear, just optimized for different use than our home gear is.

I have read on some of the audio forums that many installers have successfully used pro-amps in their setups. Most of the pro amps don't put much emphasis on appearance as a 'home' amp makers do and also the fan noise could be an issue for some people. I believe there are a few people here who have used them and like them as they do offer good bang-per-buck apparently vs consumer amps but one would need to check the specs out carefully before spending $$.

I'm only going by what I've read on other forums, I don't have any experience with an outboard amp, pro or otherwise, for the record.

Phil, a pro amp is a "true stereo amp"(if it has two output channels)and amplifies with a transparency which isn't audibly distinguishable. One possible problem is audible fan noise.

I would tend to think that at lower volumes, the fan might not actually come on(unless it's constant) and at higher volumes, which is where you'd probably be using it(otherwise why get the amp) you'd drown out the fan noise. There's also quieter fan mods out there to, if in fact, it's an issue(swapping to quieter fan, or attenuating existing one).

Some high-power pro amps, Peavey I'm looking at you, have a very audible hiss even when not fed a signal. That isn't the case for many other makers, but is something to be aware of in amps which are designed first for power, without must though to fidelity.

Any suggestions on a pro amp for home use Chris?

I did some reading, but never narrowed it down to a model which really stood out as an excellent deal. Pro amps are very utilitarian, I wouldn't mind the lack of a nice finish, and some features (like remote trigger) if the price was hugely different from other no-nonsense amps of similar power output. But when I did the math none ticked me right.

I'm also very attracted to mono-blocks. There really aren't any reasonably priced mono pro amps out there (at least that I could fine). I've been enamored by the Outlaw M2200. 200W @8Ω or 300W @4Ω, balanced input, great specs, 12-volt trigger/signal detect. $350/channel.

Though my eye has now been caught by Class D Audio's kits. They're $100 less, 600 Watts, and just so cool. But they are kits, so some assembly is required and some sort of box will have to be rigged up.

they are class D also... I cant see how a class D can sound anywhere near as good as a class A or even a class AB..?

Class D being a digital amp, is going to work on pulses, rather than a smooth signal, like a class A, granted class A amps use the most energy, and are the least efficient, and cost the most to manufacture.. but also sound the best in many peoples opinion.

I could see using a class D maybe in car audio for a sub, due to the poor acoustics...

however, it does sound like an interesting project.

Are you saying the M2200s are Class D? No, they're AB, with a variable level power supply, which makes them Class G.

Those Class D Audio kits do look cool. Get some, guinea pig.

They're on my list, but I just bought a $500 blender. Amps may all sound the same, but when it comes to smoothies, only the best blender (with analog speed control) will do.

Ha ha, what brand and model of blender did you get? I haven't had a good smoothie in a while.

Yes, but will it blend a class D amp?

It's not a Blendtec (the "Will it Blend?" people), but a Vita-Mix. Actually it's a "pro" blender, the 1709 CIA. No fancy digital displays, no programs, no modes. Just an on/off switch, and a continuously variable speed control knob. 2 horsepower (1491 Watts), and a 7 year warranty.

Good lord. Bet it would blend my Kitchenaid.

A tip, to all you cooks out there: buy a Kitchenaid Mixer. Do not buy any other Kitchenaid products--they're not worth it.

I'll back you up on that. I've owned several KitchenAid items, and none of them have been worth the premium. I'm glad to hear that at least the mixer is good.

That sounds like an insane blender. Now I want one. Thanks a lot.

I think the kitchenaid blender is a great product, as well as the mixer but all the attachments are very cool but big $$ for uslessness LOL. I think my wife has them all and we only used them to make baby food. The pasta maker/roller has only been used once.

Getting back on topic when I said "true stereo amp" I ment of a home design for home theater. I have some experiance with the pro amps for running concert equipment/dance equipment for the schools I use to teach in. As someone stated the fans can get loud, some can leave a hum and man they just are mostly but ugly. I only bought peavy gear for the schools I taught in and never had a problem but I would not put it in my family room.

Thanks for all the input,
Phil

And seriously....you guys call ME the great derailer?

"Oh yes....your the great....derailer"

"WOO-oooo-OOOO-ooo"

Anything for a Doo-Wop moment, huh?

"Duke of Derail" didn't quite work for me.

I like Duke of Derail.

Then again, I call myself the Sultan of Serotonin, the Duke of Dopamine, and the nemesis of neurotransmitters everywhere. I have Michael Buffer introduce me properly every time I make a public appearance.

Hi PhilD,

Just a few thoughts here. The other issue that may occur with pro amps is interconnection. Pro amps may only have XLR or 1/4-inch phone jack inputs, lacking RCA's because the pro world hates RCAs, understandably. RCAs are sort of crappy connectors but they are ample for home use, when you are not constantly connecting and disconnecting. In studio and broadcasting work, XLRs and 1/4-inch jacks are much preferred and more robust.

Regarding the ICE digital amps: I've never heard one, but according to our engineer Tom Cumberland, who designed Axiom's A1400-8 digital amp, the ICE amp topology had certain distortion traits that he did not like.

At Axiom we also have a couple of very powerful Yamaha digital pro amps, with fans, that we've used on occasion, including listening tests with loudspeakers. The Yamahas were/are quite expensive, and seemed to do the job just fine. I don't know what sort of amplifier topology the Yamahas use, other than the fact they are digital amps with huge output (600 watts per channel; 1200 bridged to mono, if memory serves).

Regards,

Alan

Hey, it's the Emir of Electronics!

I'll let you borrow Michael Buffer if you want.

Nice work, JP.



I don't understand.

Anytime I hear "Duke of" anything, I replace it with "Duck of" a la Unforgiven.

It makes me giggle.

Gene Hackman's character was a crackup in that movie, for sure.

Oh, I didn't know he was retired from acting and a novelist now. He played so many great parts.

I didn't know that! I really enjoy his acting.

I wonder how many books he's written?

Wikipedia said three, but I haven't searched further than that, so I don't know if it's up-to-date.

Hey, Alan, Jakeman, or anyone else, can you explain to me what is meant by a digital amp? I know that Class Ds aren't necessarily digital, and I'm betting those digital Yamahas you're talking about, Alan, aren't Class D.

In reality, ICE amps are not digital, at least that is what I've read Alan...

I am sure this joke has been done a 1000 times, but for some reason I cannot resist any longer:
Aren't those ICE amps melting at loud volumes?

There are no digital amps. The closest any come are the Zetex, Direct Digital Feedback Amplifiers, which can take PCM and convert it to PWM to directly control a MOSFET pair. But the amplification is still happening in an analog way.

No, they run cooler at higher volumes, as more of the energy is going into the speaker rather than being turned to heat behind the gate.

Hi kcarlile,

OK, get ready: these things are complicated. You are correct that class D does not stand for "Digital", although through frequent usage, it has taken root.

Class D amplifiers, although there are a number of different design variations, are essentially switching amplifiers or Pulse Width Modulator (PWM) designs. B&O's "ICE" modules are also switching designs.

The incoming analog audio signal is used to modulate a very high frequency PWM carrier that works the output stage either fully on or off. This ultra-high frequency carrier must be removed from the audio output with a reconstruction filter so that no ultra-high frequency switching components remain to corrupt the audio signals. Class D designs are extremely efficient, typically in the range of 85% to 90% or more. Axiom's A1400-8 reaches 95% efficiency at full output. Conventional class A/B transistor amps' efficiency is about 50% to 60%. The unused energy is dissipated as heat.

Regards,
Alan

Hi Sir Quack,

As Club Neon has pointed out, that's true. Further to my explanation to kcarlile, I'd add that an analog amplifier works in analogous fashion, regulating the output stage devices (transistors) to release power from the amplifier’s power supply to the loudspeakers in a manner that exactly mimics the tiny incoming audio waveform. So-called "Digital" amplifiers use high-frequency switching circuitry to modulate the output devices.

Here is an explanation of how the B&O "ICE" amplifiers work and how Axiom's A1400 differs in operation:

Denmark’s Bang & Olufsen (B&O) holds patents on its “ICE” amplifier, which is basically a Class D switching design (Pulse Width Modulator) with variants that B&O claims reduce distortion to levels associated with Class A amps, while retaining the high efficiency of Class D switching designs. ICE amps use a very high switching frequency of 384 kHz, which B&O says is 20 times as high as the highest frequency the ear can detect. The ICE amps also use feedback control to minimize the effects of the PWM design.

Axiom’s engineering division took a different approach in the A1400-8’s amplifier design. Axiom worked with International Rectifier to develop new silicon output devices that drive the MOSFETs in the output stage in such a way as to produce a perfect Pulse-Width Modulated square wave at the output before the reconstruction filter. This approach also simplifies the A1400-8's feedback network, which makes the amplifier more robust in its operation without being subject to oscillations or instability. The A1400-8 also uses a very high clock frequency to allow for excellent transient response and non-aliasing in the audio band. The massive power supply is able to accurately output very high current and voltage to the loudspeaker over extended time periods.

Alan

I'll give you my shipping address.

Ken, as the replies have indicated, although the term "digital" is sometimes thrown around rather loosely, the class D amplifiers, such as the Axiom unit, in fact operate on analog principles. The analog waveform at no time is converted by digital sampling. It's used to modulate a sawtooth triangular waveform which results in what is sometimes said to look "digital-like", but the analog waveform remains as such, but concealed by the modulation. When the several hundred KHz sawtooth waveform is removed at the end by low-pass filtering, the original(but now amplified)analog waveform is again revealed and is used to power the speakers.

Excellent information here!

Thanks, guys! I think I understand it a little better now.

Although the modulation waveform is a triangle wave /\ not a sawtooth |\.

Your welcome, glad I could start a thread too bad I can't contribute LOL

Good work, Phil!

Thanks Tom for giving credit where credit is due LOL. I think I will just get an Anthem LOL

I got my blender today. Just made an awesome smoothie. The analog speed control makes all the difference!

Chris, now you and Fredk can have yourselves a Blend-Off!

Thought I'd pass this info along. Behringer has a new 2 channel amp coming out called the EPQ450 . They don't have the full specs up yet, although they state 230Wx2 @ 4 ohms and 130Wx2 @ 8 ohms. It's a possible alternative to some of the other amps(Emo, Outlaw ect) and I've seen pre-order pricing of $199 USD online.

I've owned two Anthem amps (MCA20 and PVA7) in the past and they worked very well.

I bought them used and then sold them 2 years later at a profit. Might be something to check out. I used the CAM site for both, but I've seen them on Kijiji and Craiglist as well.

Hi Eric,

What Donlboy says is essentially true. If you bench-test pro gear vs. audiophile stereo amps, you will generally find higher levels of distortion, noisier circuitry, and noisy fans.

Now, whether or not the higher levels of distortion would be audible with music, that's highly debatable. I would think distortion would remain inaudible unless THD rises above 1% or more, but I've never done double-blind comparisons of "pro" amps vs. home stereo gear.

Ruggedness, durability and bullet-proof performance are everything in a pro amp.

Regards,
Alan

Audioholics did a nice writeup on class d amps around the time the reviewed the A1400.