PS Audio M700 Monoblock Amplifier Review

[VMAT4]

I noticed the lowest power D-Sonic stereo power amp is rated at 400 watts and I hear uses Pascal modules. It may have better numbers than the PS Audio unit here. Do the crown amps use Pascal modules as well? They seam to be quite reasonably priced per watt.

 

[GaryMnz]

Sinewaves in no way model program material. They are useless. If they were we would only use RMS for measurements.
Fail, epic.

Oh dear. Please don't claim a fail on my part when your comment only underlines your lack of understanding. You haven't understood the measurement at all have you? Do read Pano's explanation and reasoning.

 

[cistercian]

Back

I noticed the lowest power D-Sonic stereo power amp is rated at 400 watts and I hear uses Pascal modules. It may have better numbers than the PS Audio unit here. Do the crown amps use Pascal modules as well? They seam to be quite reasonably priced per watt.

Crown designed their own chip. They are proud how many components they eliminated. There is a video out there that covers it!

 

[GaryMnz]

I won't argue against low distortion.



The snare may be perceptually louder, but it is unlikely to be prompting the amplifier to output more power.

The slew rate of any competent amplifier should be sufficient to handle the frequencies and signal slope.

The output wave of an amplifier (that's voltage) will follow the wave that is input to it.

Since "most" of our modern music presses the limits of the digital medium, I don't see any additional burst of power magnitudes greater than what just came before when some different sound is produced.

The bass guitar note that digitally presses 0dBfs will excite the amplifier to produce the same voltage levels as a snare hit that presses 0dBfs. That, to me, infers the same instantaneous power output.

There are perceptual differences between the bass and snare, because of the different frequencies involved, and their concentration and timing, but if I see the same voltage level produced by different "sounds" in the recording, I don't see any of them asking the amplifier to output "absolute gobs of power" beyond what it was already doing on different sections of the music.

Well written.

 

[cistercian]

Oh dear. Please don't claim a fail on my part when your comment only underlines your lack of understanding. You haven't understood the measurement at all have you? Do read Pano's explanation and reasoning.

Your ignorance should be embarrassing. Dunning Kruger much?

 

[VMAT4]

Back


Crown designed their own chip. They are proud how many components they eliminated. There is a video out there that covers it!

Thanks!

 

[GaryMnz]

Your ignorance should be embarrassing. Dunning Kruger much?

You don't get out of it by just firing back an insult. You haven't understood Pano's methodology, that is clear from your comment. His approach is a very well constructed one that allows the average joe with just a multimeter to assess how much power he needs in his system to meet his actual needs. Its a very practical and laudible offering. The sine wave measurement is not limiting...

 

[amirm]

https://www.diyaudio.com/forums/multi-way/204857-test-voltage-power-speakers.html

Ah, so you are just going by that misguided thread. No wonder you don't give us your own data, nor understood the reference I provided to you.

A sine wave has very low crest factor of just 1.44 to 1 or 3 dB. This means its peak and average only change by that small range. It is also continuous in that kind of testing which means it will be perceived quite loud and annoying.

Music can vary but it has much higher crest factor than a sine wave Here is a James Taylor track that I happened to have open:

The average as represented by the highest peak is around -20 dB so that is our crest factor. That is massively more than 3 dB of a pure sine wave:

So you would have to multiply the numbers in that thread by a factor of 8 to get the equivalent music peak to average ratio. What they report as 30 watts then, becomes over 200 watts of musical peak power you need.

 

[CDMC]

Rubbish on the used power. I challenge you to set up a measurement of your system as used at what you would call loud normal levels and to report here.

I have done this with both a peak detector and oscilloscope in multiple situations, audio shows, retail environments, and domestic situations. The results confirmed my belied that we chase high power because the marketing guys have sold the idea to us.

In the 1970s a typical domestic amp was 25 watts. Typical speakers weren't at all efficient. How did that work?

Used to run a Yamaha M85 and Adcom GFA-5500 amp into my Magnepan MG-2.7s in a 14x17x8' room. On louder dynamic music, I could easily push the M85 power lights all the way up and would have the clipping lights on the Adcom GFA-5500 amp come on. These were amps capable of putting out 350 watts per channel into 4 ohms.

In the 70's most speakers were much more efficient, but smaller amps also clipped a lot. One of the reasons that early transistor gear was not popular was it was really bad sounding when clipped, where tubes could be pushed hard into clipping with primarily warm 2nd and 3rd order harmonic distortion.

 

[CDMC]

In the 1970s, we had LP, open reel, cassette and FM radio. Remind me, what dynamic range did we have again? 30-60dB if we were lucky.

And 1970s speakers were efficient actually. They just couldn't handle much power.

Along came digital in October 1982 with 96dB to play with. And did they ever play with it.

Remember we didn't get 96 db then, only 84 db, as 16bit converters weren't yet available. But yes, the silence was amazing compared to pops and clicks of records and the hiss of cassettes, even with Dolby B.

 

[Blumlein 88]

Oh dear. Please don't claim a fail on my part when your comment only underlines your lack of understanding. You haven't understood the measurement at all have you? Do read Pano's explanation and reasoning.

Yeah this test makes plenty of sense to me. The guy is just making it easy for non-techie's to measure what they really need for power in a simple manner using a multimeter. In this way you don't even need a peak hold meter or any such.

I've done this sort of thing myself only I used a -20 db signal. Less chance of hurting anything and because quite a few old test CD's supplied a tone or tones at that level.

Of course using Soundlab ESL's I can get some higher voltage numbers than is average for box speakers.

 

[PeteL]

Ah, so you are just going by that misguided thread. No wonder you don't give us your own data, nor understood the reference I provided to you.

A sine wave has very low crest factor of just 1.44 to 1 or 3 dB. This means its peak and average only change by that small range. It is also continuous in that kind of testing which means it will be perceived quite loud and annoying.

Music can vary but it has much higher crest factor than a sine wave Here is a James Taylor track that I happened to have open:

View attachment 77212

The average as represented by the highest peak is around -20 dB so that is our crest factor. That is massively more than 3 dB of a pure sine wave:

View attachment 77213

So you would have to multiply the numbers in that thread by a factor of 8 to get the equivalent music peak to average ratio. What they report as 30 watts then, becomes over 200 watts of musical peak power you need.

Thank you for coming up with the numbers and clear rationale. I was gonna come with the same reasoning, but you've laid it out correctly

 

[CDMC]

Has PS Audio ever explained exactly what their “gain cell” is supposed to do? I know it is a potted module that you cannot disassemble or see inside, and they have been using it for about 20 years. They’ve never really explained what it is, though.

Based on the measurements it adds some second harmonic and a lot of third harmonic distortion. It is how they make it a "warm sounding" Class D amp and charge their customers $3,000 for a $1,000 product.

 

[cistercian]

You don't get out of it by just firing back an insult. You haven't understood Pano's methodology, that is clear from your comment. His approach is a very well constructed one that allows the average joe with just a multimeter to assess how much power he needs in his system to meet his actual needs. Its a very practical and laudible offering. The sine wave measurement is not limiting...

Incorrect. I completely understand and reject his methodology. Because it is wrong. See Amirm's post as to why it is wrong.

 

[GaryMnz]

Ah, so you are just going by that misguided thread. No wonder you don't give us your own data, nor understood the reference I provided to you.

A sine wave has very low crest factor of just 1.44 to 1 or 3 dB. This means its peak and average only change by that small range. It is also continuous in that kind of testing which means it will be perceived quite loud and annoying.

Music can vary but it has much higher crest factor than a sine wave Here is a James Taylor track that I happened to have open:

View attachment 77212

The average as represented by the highest peak is around -20 dB so that is our crest factor. That is massively more than 3 dB of a pure sine wave:

View attachment 77213

So you would have to multiply the numbers in that thread by a factor of 8 to get the equivalent music peak to average ratio. What they report as 30 watts then, becomes over 200 watts of musical peak power you need.

Oh please. Do read the methodology before you respond.

two things in response:

1/ No I haven't based my argument on this approach. I am actively involved in the industry as a manufacturer and engineer. I have taken measurements as I mentioned, at audio shows (CES etc), in dealers showrooms, and in domestic situations, all using either a portable oscilloscope or a self designed peak voltage detector. Lots of data over 20 years.

2/ Pano's approach does not need to take into account crest factor etc because he sets the tone level relative to digital clipping. That means that the clip level of the system source is defined and therefore the possible peak before clipping is known.

Think it through better or read it thoroughly.

 

[GaryMnz]

Incorrect. I completely understand and reject his methodology. Because it is wrong. See Amirm's post as to why it is wrong.

See you really haven't understood it because you quote Amirm and he hasn't understood it either. It is hard to swim in a sea of ignorance.

 

[Blumlein 88]

Ah, so you are just going by that misguided thread. No wonder you don't give us your own data, nor understood the reference I provided to you.

A sine wave has very low crest factor of just 1.44 to 1 or 3 dB. This means its peak and average only change by that small range. It is also continuous in that kind of testing which means it will be perceived quite loud and annoying.

Music can vary but it has much higher crest factor than a sine wave Here is a James Taylor track that I happened to have open:

View attachment 77212

The average as represented by the highest peak is around -20 dB so that is our crest factor. That is massively more than 3 dB of a pure sine wave:

View attachment 77213

So you would have to multiply the numbers in that thread by a factor of 8 to get the equivalent music peak to average ratio. What they report as 30 watts then, becomes over 200 watts of musical peak power you need.

I don't see that as an issue with how the test was proposed. The guy is letting you find your average volume setting or if you please your average gain setting for input to output. If you knew that and know what the maximum possible digital signal is, then you know nothing can exceed that requirement at that volume or gain setting. So you'll find out the maximum voltage required of your amp. Not a perfect test, but not too bad to get you into the ballpark.

Where the test falls down is peak voltage into reactive loads could require more power than the voltage calculation into a purely resistive load indicates. If you know the impedance plot of your speakers, you could get an idea how far off it might be. Again for a simple quick and dirty test anyone can do it could provide some perspective.

If one wanted real power you'd like to have something that could graph over time both current and voltage to get you a volt-amp rating. With class D amps I suppose you could use one of those devices to monitor wattage from the wall plug and not be far off base.

 

[GaryMnz]

Guys I am surprised. I see the same blind repeating of the high power argument here as elsewhere, yet this is a "science" based forum. In my opinion the high power need is something driven by marketing departments starting back at the end of the 70s as a way to differentiate products and to charge higher prices. Here at least people should be aware of that issue and have hard data to refute it (or not). I see no data, only opinion or unfounded claims.

 

[GaryMnz]

I don't see that as an issue with how the test was proposed. The guy is letting you find your average volume setting or if you please your average gain setting for input to output. If you knew that and know what the maximum possible digital signal is, then you know nothing can exceed that requirement at that volume or gain setting. So you'll find out the maximum voltage required of your amp. Not a perfect test, but not too bad to get you into the ballpark.

Where the test falls down is peak voltage into reactive loads could require more power than the voltage calculation into a purely resistive load indicates. If you know the impedance plot of your speakers, you could get an idea how far off it might be. Again for a simple quick and dirty test anyone can do it could provide some perspective.

If one wanted real power you'd like to have something that could graph over time both current and voltage to get you a volt-amp rating. With class D amps I suppose you could use one of those devices to monitor wattage from the wall plug and not be far off base.

Blumlein88 YES!! you get it, Whew. Hallelujah.

And you do raise the point about current. No one measures the current capability of amplifiers... why not? It is important.

 

[cistercian]

See you really haven't understood it because you quote Amirm and he hasn't understood it either. It is hard to swim in a sea of ignorance.

So...crest factor and power under the curve don't matter. Got it.

That strikes me as erroneous, almost comically so. I wonder how many HF driver failures happen to those who follow
the methodology proposed occur. Because reasons.