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Review and Measurements of Musical Fidelity M2si Amp

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#22
Slightly irrelevant - I own next model up m3si , amp sounds very good, quite clean sounding. This amp also has an ok dac. I run a dedicated dac and enjoy listening via this amp.
 

trl

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#23
I am even a litle bit surprised that A/B amps are still being made.
[...]
From all the Class-D amps measured by Amir only few were able to be quiet after 20KHz and to measure really well within the audible range. And those amps were more expensive than most Class-AB tested, so no need to be surprised people is not much interested into Class-D amplifiers, myself included. Not even one amps from Pioneer Class-D is measuring comparable with their older AB-class amps (this is why I bought an Yamaha instead), so why would anyone trust manufacturers?

Hypex NC400 is indeed very good and I'd definitely purchase a couple of kits to build a stereo power amp, if I'd need one, but still the price is over 1000 EUR and preamp is missing. Meanwhile, Benchmark AHB2 is a "traditional" Class-AB amplifier that measures better, although I know there are many others out there that measure very well.
 

amirm

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#24
Does the power vs. frequency measurement take a long time to make? That one addition would likely settle many questions.
It is slower than other measurements but it is automated if we settle on one THD+N % for it to use.
 
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#25
I trust those who measure and articulate their method, however I'm not well versed technically so the following is as best I can do explaining the measurement that I think would be useful if it is possible. There are lot's of inefficient "entry level" speakers out there and lots of lauded "entry level" integrated amps that often are low on watts and those "entry" combinations end up sounding underwhelming. Even if a modern integrated has 100 watts, often it doesn't have enough capacity to handle transients. My personal example are my wharfedale diamond 230 towers, i think they are 89 db/m which is not too bad, but while they are rated at 8 ohm they dip to 3.7 ohm at lower frequencies. I have run them with various modern integrated amps and needed a subwoofer to supplement the lows until eventually I got an old Sony STR-V5 and suddenly I don't need a subwoofer and the sound seems to be more full. Is there a way to establish some sort of chart that correlates to lay people like me how well an amp needs to measure at 40-50hz to be able to power a particular empidence at the same frequency. It would be a very helpful as a cheatsheet for people on my level to interpret in a practical matter the measurements in amp reviews.
 

restorer-john

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#28
You articulate the problem well. I have to think about how to best answer that with measurements....
Power bandwidth. The frequency range at which the amplifier can deliver its rated power or half power bandwidth.

TI's definition in a datasheet:

1571031375021.png


Or you can bring the amp up to the onset of clipping at 1KHz, and then sweep it from 20-20K at that power and plot the frequency response. Amplifiers rarely go +dB in such a situation, it's always -dB and many amplifiers fail miserably at the frequency extremes.
 

BillG

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#29
Even if a modern integrated has 100 watts, often it doesn't have enough capacity to handle transients. My personal example are my wharfedale diamond 230 towers, i think they are 89 db/m which is not too bad, but while they are rated at 8 ohm they dip to 3.7 ohm at lower frequencies.
Are you referring to something like the following?

Untitled.png
 

maty

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#30
[Polish] https://audio.com.pl/testy/stereo/wzmacniacze-stereo/3087-musical-fidelity-m2si

Optimized

Musical-Fidelity-M2si-inside.jpg


MUSICAL FIDELITY M2si

Rated power (1% THD + N, 1 kHz) [W] 8 Ω, 2x 80
Rated power (1% THD + N, 1 kHz) [W] 4 Ω, 2x 103
Sensitivity (for maximum power) [V] 1x 0.3
Signal / noise ratio (A-weighted filter, relative to 1W) [dB] 76
Dynamics [dB] 96
Damping factor (relative to 4 Ω) 41

In stereo mode, the M2si achieves 2 x 80 W at 8 Ω and 2 x 103 W at 4 Ω.
 

amirm

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#31
Power bandwidth. The frequency range at which the amplifier can deliver its rated power or half power bandwidth.
What he is asking for is a system answer, not a subset. He wants to know if he has speaker X, how loud can it get with amplifier under test. We would need a model for the speaker, volume of the space, seating position and amplification power.
 

JJB70

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#32
This appears to be a pretty decent amplifier which can be bought for a reasonable price in hifi terms. You can beat the measured performance and get better functionality, and I suspect I would go for a Yamaha AS701 or AS801 but this would almost certainly be a very satisfactory performer for most people.
 

LLL

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#33
I used to know Anthony Michaelson at MF, over 20 years ago, we used to talk weekly (especially when I was writing about his products for a certain British magazine). He is definitely a great business person and his line of products certainly sells, especially in Asia where he focuses his effort. It's great to see how they truly measure up. I still have that Nu-Vista pre-amp that he gifted me when I was leaving the UK (#328 of 500, any Asian members might notice how thoughtful he was to pick that number). This set of measurement is really not bad for an A/B amp. Whether the cost justifies the performance is up to the consumer.
 

restorer-john

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#34
What he is asking for is a system answer, not a subset. He wants to know if he has speaker X, how loud can it get with amplifier under test.
I understand that, but consider what he found with the Sony STR-V5 receiver. It sounded better (he didn't need a subwoofer and the sound was more full). Why is that so for an 85W/Ch rated amplifier from 1978?

What I can tell you about that series of Sony gear (and the integrated amplifiers TAF2650/3650/4650/5650 (VFets) from the same era circa 1976/7/8ish) is they had a ruler flat response of 3Hz-100KHz, truckloads of power into low impedances and a full power bandwidth from 5Hz-40or50Khz. In short, they were technically very good and beautifully designed. They are also very conservatively rated. That said, the V5 does employ current limiting in extreme situations, but my experience was it wasn't intrusive- even on the test bench.

I have a completely original TAF-3650 (same year, same series) here which when put on my bench absolutely astounded me with how good it was for a rated 55W/ch amplifier that was 40+ years old.

His STR-V5 has a massive toroidal and weighs nearly 45lbs.
 
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#35
I have a Musical Fidelity M3i and I quite like it but I have been looking around for possible replacements. I purchased mine second hand in the UK for £400 a year or so ago. I particularly like the Home Theatre pass-through. I have listened to the M2si when demo'ing my last speaker purchase, some PMC Twenty5 22's. Anyway, I really like the website, and I keen to ensure that for any future purchases I have done a bit more due diligence.

I would also echo @AudioSceptic in that, from a UK perspective, I am keen to see reviews from Arcam, Audiolab, Cambridge Audio, and Rega, I would add Rokstan to that list also.
 

Willem

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#36
I think this is a bit disappointing. It is not a deficient snake oil product, far from it, but it does not have digital inputs, and it is not very powerful either. The Yamaha AS301-AS801 seem like better buys in roughly the same price bracket (depending on your local market).
 

audio_tony

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#37
Conclusions
The Musical Fidelity M2si is a well built and nice looking, branded integrated amplifier. Its preamplifier performance is very good but the power amp holds it back.
I didn't think the preamp performance was that good?

0.001% THD+N and 99.8dB SINAD is verging on poor for a preamp in my opinion.

I guess the lack of relays for input switching (and using an IC) doesn't help those figures much.
 

AudioSceptic

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#38
I have a Musical Fidelity M3i and I quite like it but I have been looking around for possible replacements. I purchased mine second hand in the UK for £400 a year or so ago. I particularly like the Home Theatre pass-through. I have listened to the M2si when demo'ing my last speaker purchase, some PMC Twenty5 22's. Anyway, I really like the website, and I keen to ensure that for any future purchases I have done a bit more due diligence.

I would also echo @AudioSceptic in that, from a UK perspective, I am keen to see reviews from Arcam, Audiolab, Cambridge Audio, and Rega, I would add Rokstan to that list also.
Good call. I forgot Roksan (sic!).
 
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#39
What he is asking for is a system answer, not a subset. He wants to know if he has speaker X, how loud can it get with amplifier under test. We would need a model for the speaker, volume of the space, seating position and amplification power.
I understand that, but consider what he found with the Sony STR-V5 receiver. It sounded better (he didn't need a subwoofer and the sound was more full). Why is that so for an 85W/Ch rated amplifier from 1978?

What I can tell you about that series of Sony gear (and the integrated amplifiers TAF2650/3650/4650/5650 (VFets) from the same era circa 1977/8ish) is they had a ruler flat response of 3Hz-100KHz, truckloads of power into low impedances and a full power bandwidth from 5Hz-40or50Khz. In short, they were technically very good and beautifully designed. They are also very conservatively rated. That said, the V5 does employ current limiting in extreme situations, but my experience was it wasn't intrusive- even on the test bench.

I have a completely original TAF-3650 (same year, same series) here which when put on my bench absolutely astounded me with how good it was for a rated 55W/ch amplifier that was 40+ years old.

His STR-V5 has a massive toroidal and weighs nearly 45lbs.
So, I basically understand why the Sony works, but I understand it after I stumbled across it, and wouldn't have known what to look for. Is it the headroom at 40hz or 45hz expressed as a percentage that would be the easiest way to quantify it relative to speaker spec?
 
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#39
What he is asking for is a system answer, not a subset. He wants to know if he has speaker X, how loud can it get with amplifier under test. We would need a model for the speaker, volume of the space, seating position and amplification power.
I don't actually play it all that loud. It's just with the Sony i feel like I have new speakers with much expanded range and abilities (obviously they were always there i just could not access them prior). The common wisdom on less nuanced objectivist forums is that there is little difference between transparent amps that are similar in power, but that "wisdom" does not address a lot of other variables that do matter. The Sony transformed a speaker purchase that I had been regretting for two years into something I'm very happy with. I can see how someone else with a similar experience might start believing in magic :) because as far as they know everything they heard from their lay person objectivist friend just went out the window.
I have a rudmentary understanding why the Sony works, why magic has nothing to do with it, I just don't know what mesurments I'm looking for if I was to replace the Sony, and even if I knew that I needed an amp with xx% headroom for my speakers, what happens to that percentage when I have different speakers that only go down to 5ohm instead of 3.7ohm at 45hz and so on.
 
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#40
Are you referring to something like the following?

View attachment 35955
I'm looking for a guide to relate those figures to speaker needs especially at lower frequencies.
1. If I have speakers that dip to 6 ohm at 45hz how much headroom do I need vs. a speaker that goes down to 3.5ohm at 45 hz.
2. Is the stated rms for an amplifier true across the full 20hz-20khz?
3. Does a speaker that has nominal rating of 4 ohm and dips to 3.5 ohm at 45hz have the same headroom needs as one that has a nominal rating of 8 ohm but also dips to 3.5 ohm at 45hz?
 
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