Two Power Amps: Same/Similar on paper - will they sound the same?

K

Kleinst

Full Audioholic
If you can get a high quality 4 channel amp, then you can use the Arcam to power the surround and Atmos channels. That would be the most efficient way, because your AVR should be able to drive the other channels without any issue, unless they are position further away than the front channel speakers and/or have much lower sensitivity.

For the best specs possible for such an amp, I would consider the Hypex or Purifi based amps. Examples:

AT52XNC Amplifiers (ati-amp.com)

That's the expensive option, but may be @AcuDefTechGuy could get you a good deal if you asked him;).

Otherwise as others have suggested, the Monolith 200WX5 appears to be a good option.

With the questionable Arcam's preamp output, you probably should avoid power amps with less than 28 dB gain.

In all likelihood, a good quality class AB, or G power amp won't be the bottleneck in terms of audio performance specs.
On your point of avoiding power AMPs with less than 28db gain, does that just mean you have to boost your levels a bit in order to get the AMP aligned? Does that then limit the useful power of the AMP if the pre out maxes out at some point? My guess is it still can power fine with a lower gain but makes it a little more difficult in setup.
 
AcuDefTechGuy

AcuDefTechGuy

Audioholic Jedi
Are you guys recommending the Monolith based on its performance and price point? If both were the same price, which would you get? Apologize if Im jacking the forum but doing some research before I purchase. I went to BestBuy and the Magnolia Rep recommended the Arcam PA720 Power Amp for my system (BW 702 S2 floor speakers, BW 705S2 bookshelves, BW HTM71 S2 center,, REL T-9I sub and Marantz SR5015 receiver). I have the employee discount and can get the Arcam PA720 for $1800. Performance wise, is the Monolith better than the Arcam?
Thanks!
That Arcam Amp is like the Marantz amp. It's basically like the amps inside the AVRs. Since you have a Marantz AVR, if you are going to use an AVR-derived amp, might as well get the Marantz Amp to match aesthetics, which will also perform like the Arcam amp.
 
P

PENG

Audioholic Slumlord
On your point of avoiding power AMPs with less than 28db gain, does that just mean you have to boost your levels a bit in order to get the AMP aligned? Does that then limit the useful power of the AMP if the pre out maxes out at some point? My guess is it still can power fine with a lower gain but makes it a little more difficult in setup.
That depends, if your preamp has good performance specs/measurements at high enough output voltage such as 2 V unbalance, or 4 V balanced then even 26 dB gain would be fine unless you need more than 200 W into 8 Ohms.

Another example, if it can only do well at say 1.5 V, and you need more than 100 W into 8 Ohms then 26 dB gain would be too low. If you tell me which preamp, power amp, and your max power need I can do the calculations for you.
 
AcuDefTechGuy

AcuDefTechGuy

Audioholic Jedi
If you can get a high quality 4 channel amp, then you can use the Arcam to power the surround and Atmos channels. That would be the most efficient way, because your AVR should be able to drive the other channels without any issue, unless they are position further away than the front channel speakers and/or have much lower sensitivity.

For the best specs possible for such an amp, I would consider the Hypex or Purifi based amps. Examples:

AT52XNC Amplifiers (ati-amp.com)

That's the expensive option, but may be @AcuDefTechGuy could get you a good deal if you asked him;).

Otherwise as others have suggested, the Monolith 200WX5 appears to be a good option.

With the questionable Arcam's preamp output, you probably should avoid power amps with less than 28 dB gain.

In all likelihood, a good quality class AB, or G power amp won't be the bottleneck in terms of audio performance specs.
You know it, bro. ;)

 
B

BlackSpider777

Audiophyte
I know this is an old thread, curious which power amp did the OP go for?

Thanks.
 
K

keith gould

Audiophyte
I have an Arcam av860 with an Arcam P390 powering the front 3 and a Emotiva 5 channel amp powering the 4 rears.
Ive tried the Emotiva on the front and please believe me the Arcams sound quality is far better than the Emotiva.
I know the question was concerning a Monolith but from what i understand the sound signature is similar.
Its the all important midrange which is the difference. The Emotiva starts to get a bit shouty and harsh when driven hard where the mids from the Arcam retains the smoother and heavier HIFI quality.
Yes the PA720 has less power than the P390 but i have used the AVR850 with same amps without any problems and the PA720 power supply isnt sharing with the processor which should help.
Im planning to replace the Emotiva with an Arcam when funds allow.
Yes the Arcam is more expensive but IMO its well worth the extra.
 
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Verdinut

Verdinut

Audioholic Ninja
I have an Arcam av860 with an Arcam P390 powering the front 3 and a Emotiva 5 channel amp powering the 4 rears.
Ive tried the Emotiva on the front and please believe me the Arcams sound quality is far better than the Emotiva.
I know the question was concerning a Monolith but from what i understand the sound signature is similar.
Its the all important midrange which is the difference. The Emotiva starts to get a bit shouty and harsh when driven hard where the mids from the Arcam retains the smoother and heavier HIFI quality.
Yes the PA720 has less power than the P390 but i have used the AVR850 with same amps without any problems and the PA720 power supply isnt sharing with the processor which should help.
Im planning to replace the Emotiva with an Arcam when funds allow.
Yes the Arcam is more expensive but IMO its well worth the extra.
Any amplifier, when driven beyond its designed limits will sound harsh, not only the Emotiva! The purpose of an amplifier is to increase the signal voltage of an audio source, without modifying the form of the incoming sound waves with any form of distortion and added audible noise.

Well designed amplifiers, when driven within their limits, all sound the same, period. When an amplifier is struggling to drive a low impedance loudspeaker, it has exceeded its designed limits and doesn't perform adequately because of its limited power supply current.
 
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P

PENG

Audioholic Slumlord
I have an Arcam av860 with an Arcam P390 powering the front 3 and a Emotiva 5 channel amp powering the 4 rears.
Ive tried the Emotiva on the front and please believe me the Arcams sound quality is far better than the Emotiva.
I know the question was concerning a Monolith but from what i understand the sound signature is similar.
Its the all important midrange which is the difference. The Emotiva starts to get a bit shouty and harsh when driven hard where the mids from the Arcam retains the smoother and heavier HIFI quality.
Yes the PA720 has less power than the P390 but i have used the AVR850 with same amps without any problems and the PA720 power supply isnt sharing with the processor which should help.
Im planning to replace the Emotiva with an Arcam when funds allow.
Yes the Arcam is more expensive but IMO its well worth the extra.
Unless you did it in a controlled DBT, people can believe you heard what you thought you heard, not much more than that though.
 
ski2xblack

ski2xblack

Audioholic Field Marshall
Class g (and h) are/were just methods to reduce heat in conventional a/b amps. They use the same class a/b output stages, but the power supplies are dual rail (or variable, in the case of 'class h'). As mentioned, such supplies are of necessity more complex, with much higher parts count and increased chance of failure.

Also, it throws a wrench into amp comparisons when using continuous power as the metric. A class g amp's power supply will have a low voltage rail that can run 24/7, and a high voltage rail that can operate for a second or two. The standard 'continuous power' rating will reflect the lower voltage rail's limits, where with dynamic program material the class g amp might punch above what it's continuous rated power suggests. It's a ratings game that NAD has historically engaged in, as one example, touting their IHF rated power specs. I have no idea what Arcam specifies or what salesmen believe, but amp performance is all reducible, if only that info was disclosed. In the real world, listening to music, I doubt that there's a hill of beans difference between those amps, maybe a db or two of headroom?

Modern amp tech renders obsolete such approaches anyway, but OP was asking about class g. No, if one can actually hear rails commute (the primary difference b/t the Arcam and Monolith, and something that happens at power levels where speaker induced distortion wildly dwarfs that from the electronics), they either have superhuman senses or delusions of such powers.

So, for almost twice the ducats, the Arcam might, might, approach the absolute power of the Monolith for dynamic signals. If both amps can achieve similar amounts of clean power, why go with the more expensive, more complex option? That's a $1400 difference that could go toward actual audibly beneficial improvements.
 
K

keith gould

Audiophyte
I listen at reference volume levels and i can notice that the Emotiva does begin the struggle where as the Arcam doesn't which is why I'd spend the extra money.
I don't know what's going on inside I just listen and make a decision that way.
I've been lucky enough over the years to own amps from Chord Electronics Bryston Atc and similar all with different internal designs running both ATC and PMC 3 ways and I've always needed large quality amps to get the best out of them ie control and detail at high volumes.
I currently have 7 smaller ATCs for home theatre and they are power hungry and I find the Emotiva lacking hence in part my amplifier decision.
But we all hear differently and make up our on minds that's why we love a discussion right?
So the original question would they sound the same? It depends on the users needs and ears.
I know at decent levels I need the quality sound of the more expensive amp and also even at moderate levels i can hear more detail from the Arcam
I did an A/B test for and hour just listening to the famous Jurassic park scenes (sad i know i should get a life) and the T Rex growl had more detail and texture with the Arcam.
I dont know but maybe Arcams HIFI DNA requires more midrange detail and its making the difference?
 
P

PENG

Audioholic Slumlord
I listen at reference volume levels and i can notice that the Emotiva does begin the struggle where as the Arcam doesn't which is why I'd spend the extra money.
I don't know what's going on inside I just listen and make a decision that way.
I've been lucky enough over the years to own amps from Chord Electronics Bryston Atc and similar all with different internal designs running both ATC and PMC 3 ways and I've always needed large quality amps to get the best out of them ie control and detail at high volumes.
I currently have 7 smaller ATCs for home theatre and they are power hungry and I find the Emotiva lacking hence in part my amplifier decision.
But we all hear differently and make up our on minds that's why we love a discussion right?
So the original question would they sound the same? It depends on the users needs and ears.
I know at decent levels I need the quality sound of the more expensive amp and also even at moderate levels i can hear more detail from the Arcam
I did an A/B test for and hour just listening to the famous Jurassic park scenes (sad i know i should get a life) and the T Rex growl had more detail and texture with the Arcam.
I dont know but maybe Arcams HIFI DNA requires more midrange detail and its making the difference?
The thing is, doubling the "power" output will give you 3 dB more spl so if you are using a Yamaha receiver, that would mean a difference of 3 clicks on the volume dial if 1 click represents 1 dB, or 5 clicks if 1 represents 0.5 dB will separate the clipping point of a 100 W vs 200 W amp, all else being equal.

To understand if it is a fact that your Emotiva would begin to struggle at lower output level than your Arcam you just have to compare their power output specs and your speaker's impedance/phase angle characteristics.

If both (the Emo and the Arcam) are operating at well below their rated output specs, then the difference you heard would likely disappear if your do a controlled comparison test with your ears, but with your eyes closed so you don't know, and cannot even guess which one is doing the amplification. So again, yes you are correct that "It depends on the users needs and ears.", but only if you don't know which amp you are listening to. I know it is hard to believe as you may really think you hear such an obvious difference, such as hearing things you didn't hear before, better soundstage etc.etc.., usually favoring the more expensive amp that you have read about how good they sound before your purchase, making it unnecessary to do any controlled tests other than a simple volume match, let alone DBT or even SBT.
 
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