Tuesday, 17 April 2012

Musical Fidelity M1 PWR Power Amp

This must be the most non conventional and challenging review I have done so far. This is due to the following reasons:

1. First time I am listening to a Class D amp. I didnt know what to expect. Maybe this is a good thing, maybe not.

2. Although the manual says that it matches the M1, M3 and M6 series of MF amps, I was still skeptical due to the different power rating and also different class of amp. My M6i is a Class A amp.

3. I am using Siltech and QED to bi amp the D18s at the moment.

A little bit something about the PWR amps.


The PWR is designed in a shoe box size, to match the rest of the M1 series. It comes in either black or silver finish. Of course I opted for the black since the rest of my kit is black.

It weighs 3.9 KG unboxed. Light for a power amp to me.

The finishing, front and back fascia is as expected to be of good quality. The front fascia comes with soft push Power/Standby switch (with LEd indicators) plus another 2 LED indicators for mono and temperature.

The LED for power/standby however, MF seems to be inconsistent in its design of the differnt components in the M series.. Each different unit have different indicator LED:

1. M1 CDT - Amber for standby, no light for On

2. M1 CLiC - Amber for standby, blue for On

3. M1 HPA - Amber for standby, blue for On

4. M1 ViNL - Amber for standby, no light for On

5. M1 DAC (first edition) - hard push button with blue for On.

6. M6i amp - hard push button with blue for On

7. M1 PWR power amp - Amber for standby, blue for On.

This actually bugs me quite a bit. Odd eh?

On the rear, 2 pairs of left and right speaker terminals, mono/stereo switch, input and loop out RCA connection and also low voltage trigger switch.

It comes with a UK 3 pin power cable which I like.

Basic specs

It is suppose to provide:

1. In stereo mode - 65 WPC into 8 ohm and 130 wpc into 4 ohm

2. In mono mode - 100 WPC into 8 ohm and 200 WPC into 4 ohm

So, why Class D? Feedback from Antony Michaelson - It suppose to operate more efficiently and produces less heat.

As far as I know, Class D amps have been around for sometime. However, though it might be more efficient ie less heat, smaller heat sinks etc, it has not been able to produce high quality sound as most audiophiles long for.

The set up

LTB Enterprise provided me a pair of these PWR power amps eventhough I actually one needed one to bi amp my D18s.

So, I had the chance to have a few set up configurations:

1. Bi amp in mono mode (using Siltech 330L and QED Silver Anniversary XT)

2. Bi amp in stereo mode (using Siltech 330L and QED Silver Anniversary XT)

3. Direct single wiring to the PWR in stereo from the CLiC (using Siltech 330L)

NOTE: for set up 1 and 2 above, the PWR amps are used to run tweeters.

The Session

Review was done using the following tracks:

1.Aaron Neville - Louisiana on CD

2. Andrew Bocelli - Time to Say Goodbye on CD

3. The Eagles - Hotel California on 24/192 hi res via CLiC

4. Eric Clapton - Tears in Heavan on LP

5. Foo Fighters - My Hero on MP3 320 kbps

First in mono mode, I Immediately noticed the way the D18s reacted when bi amped. Mind you, when I bought the D18s, I was bi amping them with my previous MF XA1 and XA50 monoblocks amplification and I really liked it. So, first and foremost, I am re-convinced that I personally can and able to hear differences when a speaker is bi-amped.

However, fresh from the box, these PWR sounded a bit bright on the tweeters. Sad to say, on tracks by Aaron and Andrea, the high end vocals can be a bit pinching to my ears and sounded very sharp. It can really overwhelm the bass of the D18s that were driven by the M6i.

I was a bit concern to then play the hi res Hotel california. But nevertheless, still tried it on and as expected can be a bit shrieking sounding. At this point, I was rather disappointed.

Playing Eric on LP took away that high pitch sound from the tweeters. But then I attribute that to the TT and M1 ViNL.

Playing My Hero (lots of bass pedal), I noticed that the bass is very detailed and controlled. Each kick pedal and toms played on this track can be heard clearly. But, I believe this is an effect of bi amping and not necessarily due to the PWR amps.

Ended the first night with a mixture of thoughts:

1. Bi amping my D18s is good to me

2. Is the PWR power amp a good match to my M6i and D18? NOT Sure.

I then let the unit run in with Hotel California on repeat th whole night.

The next morning, I had a listen for 30 minutes before leaving for work and let the unit run in the whole day. It sounded a bit different but still did not convince me.

After running in for 24 hours, to my despair, still not much different.

Is 100 wpc to run tweeters is an overkill? I ask myself. Maybe. Maybe not.

I then switched to Stereo Mode.

My my my...dont ask me why and how. It completely changed the sound stage. The PWR are still running the tweeters but its no longer sounded high pitched. In fact sweet, luscious and fluid are some of the description I can say about this power amp.

So, does mono vs stereo mode makes a different? To me yes. Is it due to the difference in power supplied by the modes? Not sure. Or is it due to the Class D sound characteristics?

The vocals of Aaron and Andrea sounded very uplifting and there is a small injection of clarity. It just sounded clearer and more detailed than before.

The best improvement from switching to mono mode is on Hotel California and My Hero. The shrieking sound has gone and Hotel California sounded bold and nostalgic. There was a moment that one can feel re-living the yesteryears.

And on My Hero, I can just feel the openness injected into the listening atmosphere. It just compliments further the controlled bass on the D18s from the M6i.

Now, 2 elements have come into place:

1. Effect of bi amping

2. Operating mode of the PWR amps

I have deduced the following:

1. Bi amping my D18s have provided me with a more controlled low ends

2. The different operating modes of the PWR amps have effects on the sound produced (especially if it is used to run tweeters)

So, for the final review, how does this PWR perform on its own? So I took out the bi amping element by connecting the PWR amps in stereo mode to the CLiC via the Variant RCA Connection. NOTE: Volume is now controlled by the CLiC. I then single wired the D18s to the PWR using the Siltech 330L speaker cable.

I can only now use Hotel California and My Hero as music reference.

First I notice is that I needed to crank up the volume (digitally) on the volume to about ¾ of a full bar to get a decent listening volume. However, the characteristics of the sound I heard before was still there. The high pitch was there but since its also running the woofers on my D18s, it did not really overwhelm the low ends of the listening experience. I lost the low ends control that I was enjoying when the D18s were bi amped.

I had to repeatedly tell myself NOT to compare with M6i amp as I started to discredit the PWR amps. It’s not a fair comparison between them. And my quest to bi amp my D18s should not be compared or linked to M1 PWR amp performance.

Putting that aside, I must say the PWR power amps compliments the CLiC quite nicely. Can it run my D18s? Yes it can do that. No struggle at all. Will it be an easy match to any speakers? I would have to say NO. You will have to audition these babies with your own speakers. In general, I feel that this Class D amp matches well with speakers without metal tweeters. If I still have my EPOS M12.2, I would give it a go just to proof to myself this feeling.


1. The M1 PWR power amp on its own is a great value for price (RRP at RM4300 each) given its switchable mode between stereo and mono. It will fit nicely with streamers or CD players with digital volume control output.

2. Will it match any integrated amps and speakers for bi-amping? Need to demo them on your own although I believe that the Class D is providing this high pitch sound characteristics. So, proper matching of amps and speakers for biamping is vital.

3. Will I purchase them to biamp my D18s with M6i amp? Not in mono mode (2 units of PWR) definitely. In stereo (1 unit), maybe. I will continue listening to it till end of this week in stereo mode, bi amping my D18s.

1 comment:

Unknown said...

I have 6 of these amps feeding Pmc Pb1i speakers directly treble mid and bass without crossover.

I have an M8 pre a M6 sdac and a Cyrus Signature transport with appropriate high quality connections. I have had quality hifi for over 40 years and I say that there is nothing I have heard to beat these amplifiers in terms of pure sound quality and running costs, please someone let me know where I can get a dozen more for my av pre amp.