Musical Fidelity M250 Monoblock Power Amplifier
by Karl Lozier
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We have now reached the end of the music reproducing chain for Musical Fidelity's products. In September I
reviewed their model A3.2 CD
player. Last month I followed with a review of their A3.2
pre-amplifier. Their reproduction chain ends with their new M250 monoblock power amplifiers. They are certainly a bargain at just under twelve hundred dollars each and offering a hefty 250 watts. As with the other reviewed products by Musical Fidelity, I find them to be esthetically pleasing with matching brushed aluminum faceplates. The overall shape is substantially different than the other units. Overall and at a glance, the M-250s appear to be half of a typical stereo amplifier or a bit less than half at just seven and a half inches wide. If you are familiar with PS Audio's model 300 Power Plant you will be aware of the visual similarities. Give consideration to the units' overall depth at approximately eighteen inches. When various cables are plugged in at least twenty inches of overall depth behind the faceplate are needed. Two of these amplifiers placed side by side as if they made a stereo amplifier are very attractively styled as if a unit or stereo model.
There are a few unusual features on this model. On the front panel are two
LEDs. First the power rocker switch on the real panel must be pressed. Then the orange LED on the front panel will come on, that is simply a visible conformation that the amplifier is ready for use in what they term the "audio sense" mode. In that mode the M250 will turn on when an input signal is detected. This arrangement is commonly used with separate subwoofer systems as typically seen in home theater setups and is very convenient. As soon as the input signal is detected the amplifier is on and the front panel's blue LED will be lit letting the user know the status. The blue LED is referred to as the "operate" LED. Pressing the front panel power status button does the same thing i.e. putting the amplifier into the operate on mode. It is a simple and intuitive arrangement and just a bit harder to explain. In any event, if after approximately fifteen minutes no audio input has been sensed, the amplifier will revert to the "audio sense" mode. Again, this is as with most separate independent subwoofer systems.
The Musical Fidelity M250 features an unusual additional feature (actually two unusual features and this is just one of them) they call a "trigger mode". It is another way to control on/off function and requires a plugging in to a corresponding socket on the rear panel. This is basically a form of electronic switching the "audio sense" mode. I doubt if many typical users will avail themselves of this feature and I'm not going to attempt to explain it. The other unusual feature is the amplifier's ability to easily be used for bi-amplification. The following four sentences are a direct quote from the amplifier's installation guide, itself a model of clarity. The M250 has a "loop output" socket (rear panel) to allow "bi-amplifying" of a speaker with suitable active or passive crossover networks. This socket is directly linked inside the amplifier to the "line input socket to enable onward connection to a further unit, such as another M250, (of course a different additional amplifier could be used, such as a low powered unit for the tweeters, etcetera). In this arrangement, typically one M250 is used to drive the "tweeter" and one to drive the woofer of each loudspeaker enclosure. Thus, four M250s would be needed for a stereo pair of two or three way loudspeakers.
Hookup was straightforward with one exception. The 4mm banana plug holes are fitted with plastic blanking pieces in order to comply with the European safety regulation BSEN60065. Removal of the blanking pieces invalidates any electrical safety approval of the M250 amplifiers. My guess is most listeners with banana plugs, particularly if they are the fine WBT locking ones, will remove the blanking pieces, but I did not do so. As with
my reviews of the Musical Fidelity A3.2 CD player
and last month's A3.2 pre-amplifier, all my personal current lineup of components was used when listening to Musical Fidelity's fine M250 monoblock amplifiers.
The previous two Musical Fidelity components are similar overall, both physically and sonically. Though perhaps slightly oversimplified, my impressions were of an elevated mid-bass to upper-bass range and a slightly sweetened, or somewhat softened treble range. In addition a subtle lack of output in part of the midrange gave a somewhat distant perspective to their soundscape presentation. Overall it had been rather easy to describe the attributes as very musical by adding to the sometimes rather anemic bass offered by some recordings. On the other side of the listening coin, the somewhat subdued treble particularly in the highest frequencies with massed instrumentation or groups was made more pleasing by usually reducing much of any harsh edginess or distortions in that range. All these made for very musical sounding components.
At first I thought the M250s were repeating these same characteristics. Further listening proved that to not be completely true. In at least the mid-bass to upper bass frequencies there was a slight amount of added output. I refer to it as a musically pleasing enhancement. It must be kept in mind that my usual reference amplification is a pair of Herron's model M-150s. Unlike Herron's other audio products it is solid state. Keith Herron is basically a tube lover for sound quality and what he can do with tubes. He also acknowledges the real and potential problems with tubes when used in power amplifiers. Problems can arise with higher voltages, limited supplies of excellent sounding tubes and the unpredictability of tube life even with thorough testing. The result of his reasoning was a solid-state amplifier that has much of the life-like clarity and sparkle in the top end of fine tubed gear. Nobody has ever thought that they have the pleasing added fullness and extra richness of the better-tubed amplifiers; they simply do not add anything in the bass range, nor do they subtract.
As of this writing, Herron told me that for the past few months all Herron amplifiers sold have had a modest upgrade that results in a noticeably fuller sound in the mid to upper bass range area. Unfortunately I have been so busy that I have not had a chance to have my pair updated to their current standard. For the nonce it is quite apparent that the Musical Fidelity M250 amplifiers have noticeably more output in much of the bass range than my reference Herron amplifiers and that fact is not a negative. It simply has a slightly different tonal balance, though the Herrons at more than double the price do reveal more detail and information in even the bass and lower mid-range than the M250s.
Moving higher up in the musical range I found the all-important midrange to be quite good. On most recordings I felt that a small degree of lushness was being added which was well within the limits that can be referred as neutral. Detail in this area was subtly less than that presented by the very best amplifiers I have heard, all of which are significantly more expensive than these very moderately priced M250s from Musical Fidelity.
Moving still higher in the audible range I found some relatively distinct differences in tonal balance as compared with Musical Fidelity's CD player and
pre-amplifier. With the CD player I naturally assumed it was the result of their well promoted upsampling technique and figured the
pre-amplifier was deliberately "voiced" to sound that way also. With these amplifiers I did not perceive deliberate "voicing" in the
upper frequency response. As a result the highs and in particular the elevated audible range of full orchestral sounds at
peak listening levels were definitely not covered over but very openly revealed. This is not always a desirable trait as so many of the CD recordings of the first twenty or so years are a bit harsh or edgy sounding and not particularly musically appealing when clearly revealed.
One of my favorite albums when I want to simply relax and enjoy familiar old songs sung by an excellent baritone is Frank Sinatra's
"The Very Good Years" (Reprise 26501-2). It is a compilation album with the first sixteen songs recorded at different times and locations in the mid sixties and the last four were recorded in the nineteen seventies. On most of the selections a small bit of that old time digital edge or hardness was audible, mainly from the various orchestras not the famous "chairman of the board". Unlike most male vocalists, he is equally outstanding from quiet ballads to the hippest swinging jazz compositions. Few male vocalists can possibly claim that.
Moving into the next century and switching to a piano-orchestra combination recently released as Telarc Rachmaninoff's Concerto No. 3 (Hybrid SACD-60582) is an outstanding recording (see this month's music reviews). Here at times in the loudest passages for massed orchestra I found some of the same problems evident, however briefly. Switching to the same company's recent Hybrid SACD-60574 featuring Debussy's
Iberia and also viewable on this month's music review, nothing was amiss in that entire piece of music. I leave it to you readers and listeners to figure that out. In the superb analog based High Performance series by BMG/RCA) the
Bizet/Schedrin version of the
Carmen Ballet (RCA 09026-63308-2) came through outstandingly good except when one of the many, and I do mean one and only one, of the many metallic percussion instruments was a bit too much to come through cleanly and clearly in its very high frequency range without harshness.
All in all the Musical Fidelity M250 amplifiers seem to be excellent performers in their very moderate price range. In addition consider the nice esthetics and high power. What more can be expected from a pair of monoblock amplifiers from merry old England compared against most stereo amplifiers with lesser power and esthetic appeal from the good old
U.S. of A.?
Frequency Response: 10Hz to 100kHz (+/- 2dB)
Power Output : 250 Watts into 8 ohms (24dBW)
Intermodulation Distortion: 0.006% at 1kHz up to 90% power, into 4 or 8 ohms
Peak-To-Peak Output Current: 72 Amps
Output Devices: Six
Input Impedance: 31Kohm
Signal To Noise Ratio: > 115dB 'A'- weighted
Dimensions (approximate): 7.5 x 18.5 x 5 (WxDxH in inches)
Weight (approximate): 26.5 pounds
Musical Fidelity Ltd.
Wembley England, UK
North America Distributor
Kevro International, Inc.
902 McKay Road