There is a fortunate trend in headphone design these days, the inclusion of an onboard DAC with this USB input. The advantage of having a DAC in a headphone amp is obvious – not only does it enable the headphone amp to be used in a customary fashion, for example, connected to a mobile device or the record-out of a preamplifier or an integrated amp, but to be connected to the USB output of a computer. This will transform any computer with music files on its hard drive (hopefully full-resolution non-lossy files) into a high-end system simply by adding a pair of high-quality headphones. The Musical Fidelity M1 HPAP headphone amp not only sports RCA line inputs, but both fixed and a variable line outputs. This allows the M1 HPAP to act not only as a headphone amp, but as a line preamplifier if one wishes to connect it to a power amplifier. One could also use the fixed output as a pass-through to connect whatever the headphone amp's cables displaced when it uses the record-out on the preamp.
Headphone amps that are designed around a Class A amplifier, which includes the Musical Fidelity's M1 HPAP, are rather common these days. But just as important are other internal design characteristics such as its power supply, and in their literature Musical Fidelity claims that their M1 HPAP is built with a high-current, low-noise power supply. This is most likely one of the reasons why the M1 HPAP not only can drive any set of headphones that are connected to its input jack, but why I found that this headphone amp sounds so darn good. Other traits that have found their way into headphone amps are making them more user-friendly in that they might have multiple input sources, but admittedly, none of these are as important to some users as the USB input.
My conclusions regarding the sound quality of the Musical Fidelity M1 HPAP are based on not only its performance when connected to a preamplifier's record-out, but also to a computer's USB output, and by connecting a mobile device to both the M1 HPAP's line input and its USB input. It goes without saying, but I will say it anyway, these conclusions take into account not only the quality of the source component but the method in which the M1 HPAP was connected. Lastly, I tried using the Musical Fidelity M1 HPAP as a preamplifier.
Details And Connections
Connecting the M1 HPAP to my system in my main listening room was simple, but also in my second system, both of these quite big steps above the average desktop system. I figure that yes, many will be purchasing the M1 HPAP to connect a USB cable from the computer directly to the headphone amp's USB input. But there are still many audiophiles that will be looking for an inexpensive headphone amp that is more than a cut above the internal headphone amp that is feeding the headphone jack of a DAC, integrated amp, CD player, etc. Therefore, I auditioned the Musical Fidelity M1 HPAP as if it was going to be used by an audiophile because, after all, this is an audiophile publication. So, I started out by hooking up a run of Audio Arts IC-3SE between a Balanced Audio Technologies preamplifier's record-out into the line input of the M1 HPAP. The majority of time was spent using the superb Grado PS-1000 (reviewed in the October 2012 issue), but during the course of the review I also used a set of older Sennheiser HD 600s (reviewed in the July 2002 issue) that was recently restored by Sennheiser USA, and the over-achieving less than $100 Grado SR-80. The analog source was a Basis Debut V turntable with Lyra Kleos phono cartridge mounted on a Tri-Planar 6 tonearm. The phono preamplifier was a Pass Labs XP-15. The interconnects running from the cartridge to the phono preamp was the Discovery cable terminated with Cardas RCAs hardwired in the tonearm, and a balanced pair of MIT cables that ran between the phono preamp and the BAT. The digital source was mainly FLAC files on a PC running Foobar 2000. The computer's USB output was connected with Furutech GT2 USB cable to the DAC, a Wadia 121 Decoding Computer.
I don't think I'll be booted out of any audiophile clubhouse by admitting that I spent some of my time listening to the M1 HPAP headphone amp with my iPod. This 160GB iPod's drive is just about filled to capacity with lossless AIFF files. These files, most of them guilty pleasures, are sonically identical to full bandwidth WAV or FLAC files, at least when played through my iPod. I suppose if one presses their ears to the grilles of $100,000 speakers with a similarly price front-end when to compare these types of lossless files one might hear a difference in their sound... or perhaps not. Anyway, that's not the point, because these files on the iPod sound top notch, and were at least somewhat helped by bypassing the iPod's internal audio section by using a SendStation Pocket Dock Line-out adaptor that clicks into the iPod's dock connector.
Musical Fidelity M1 HPAP
The sound of this digital burn of the Dust LP was extremely enjoyable through the M1 HPAP. Despite the relative insensitivity of the Grado PS-1000 ‘phones, this headphone amp was able to drive them to a comfortable level without the amp's control ever passing its halfway point. One of the strong suits of the PS-1000s is their spectacular separation of instruments, and through the M1 HPAP this trait was fully evident. Kenny Aaronson's bass occupied the bottom center of the ‘stage, its sound was a bit more pumped up in the mid-bass than deep-bass heavy, although the blame can't entirely be placed on the M1 HPAP, mostly due to his Fender bass recorded this way. The bass sounds as it was recorded as a mixture of live and directly to the sound console, which still enabled a bit of amplifier distortion to enter the sonic picture during the crescendos, which were many. The instrument had enough transient information to make each note not only audible but sound like an actual bass guitar.
Rickie Wise's overdriven Gibson SG was double and sometimes triple-tracked, one rhythm guitar panned to each speaker, but when he would solo the engineer would usually sweep this guitar to the center of the mix. Occasionally reverb was added, the sound of the ‘verb reproduced in a separate space in the soundstage. When Richie Wise played acoustic guitar it had a very lifelike timbre through the M1 HPAP, displaying a very transparent midrange, the headphone amp's best trait. Along with the excellent transient response I spoke of, the occasional appearance of his acoustic guitar was a perfect display of the M1 HPAP's way of injecting a sense of credibility into a recording, and was evident in every instrument that had a strong midrange presence. This of course was true with the vocals, which the M1 HPAP was quite proficient at reproducing, whether these vocals were male or female.
The early 70's intentionally muted sound of the drums on Dust's debut album were spread throughout the soundstage, except the sound of the cymbals, which had a more natural splashy character, their initial strike integrated into their sound yet never becoming artificial sounding. The vocals were a typical multi-track display, obviously recorded as a separate event at another time in a room other than the rest of the band; yet relatively natural and without undue sibilance. I feel a bit strange speaking of the sound quality of the Musical Fidelity M1 HPAP as distinct occurrences, its sound was very musical, as it was not one that lent itself to easy dissection but as a rather transparent reproduction of what was laid down to tape so many years ago. There was a bit of darkening of the sound – not that I thought the treble seemed excessively rolled-off, instead it has a sound that's more than a bit warmer than most solid-state devices in this price-range. It still rocked.
I played plenty of the classics through the Musical Fidelity M1 HPAP headphone amp. Historically, Sibelius' Sixth Symphony is one of his least played. Not his only one of his least played in the concert hall, but in my home. Lately, I've been trying to remedy the situation. Perhaps it is its more accessible sound that turns me off, as works such as his Fourth Symphony have such a foreboding, bleak sound that is more to my liking, especially when I was younger and first started enjoying Sibelius' symphonies and overtures. So this piece has always struck me as being one of his more conservative works. But I've been told it was one of his masterpieces by quite a few friends and critics, so I spun it both on CD and record many times throughout the last couple of years. Although it is "lighter" than my favorites, it still has his sonic signature all over it. And even though there are some folk music elements, there is still a pulsing undercurrent that I appreciate, and the M1 HPAP's excellent reproduction of the all-important woodwinds that introduce its thematic elements that set the stage for not only for the rest of the first movement, but the rest of the short symphony (it clocks in at only 30 minutes). This symphony and much of the other classical works I've played through the M1 HPAP show that this headphone amp has certain "rightness" to it. And again, although its sound leans toward the yin rather than the yang, I'm still not ready to declare that its treble is objectively rolled-off.
On Paavo Berglund's version of the Sixth with the Chamber Orchestra Of Europe, with their reduce forces one might assume would yield a less compelling rendition of this piece. But as I have written before about Berglund's readings of Sibelius with this orchestra -- the smaller forces allows one to more closely hear the inner workings of Sibelius' orchestration without losing any of its emotional power. Even more than hearing the Sixth as played by this smaller ensemble was the joy of hearing it through the M1 HPAP through a decent pair of headphones. The first movement begins with what sounds innocent enough, the high strings playing extended motifs that last for what seem to be at least a half measure each – calming chords with supporting winds, thematically simple and not at all challenging. But as expected, things turn quite Sibelius-like less than halfway through the short movement. The M1 HPAP was able to reproduce not only the string tone with more transparency than not only a headphone amplifier at this price has any right to, but more than headphone amps costing much more. Sibelius doesn't challenge the highest frequencies with any metallic percussion, the only percussion instrument he uses are tympani. But still, even though the treble is slightly softened in the very top of its register, was just about as lifelike as I've ever heard it through a pair of cans.
The horns enter about three quarters through the movement, and by that time we are treated to a sunny day spring day in Finland, the melting snow gives way to brooks of spring water and thaw. I know, I know, it sounds as if I'm getting a little soft in my old age, but there is an undercurrent of melancholy throughout the symphony that I find quite appealing, and even though this headphone amp isn't the most detailed sounding I've ever heard, the M1 HPAP reproduces enough detail that I was able to hear every note from every instrument and group of instruments as well as the rebarbative character of the hall it which the symphony was recorded. It certainly is surprising that for a headphone amp that is so affordable is able to retrieve this amount of detail. But music is much more than detail. Some call this the gestalt of the musical signal that passes through an audio component. The M1 HPAP made each and every instrument and group of instruments not only sound quite lifelike, but quite musical, involving, and that these instruments were being played and conducted by human beings in a real space.
The above musical examples were culled from my time with various sources connected to the headphone amp's RCA line inputs. I have not had the pleasure of hearing the model that the Musical Fidelity M1 HPAP replaced, the M1 HPA. But I have read some reviews of that unit, and although most reviewers were very pleased with its performance a few noted that the sound quality of its USB input was not nearly as good as its line input. When I compared the inputs of the M1 HAPAP during the same listening session, I discovered that those reviews were at least partially correct in that this trait could be applied to this new model -- the USB input's sound does not scale the same heights as the line input. However, the USB input doesn't sound bad, just lacking some of the presence of the line input -- the mid-bass does not sound as full; in fact the overall sound is a bit thinner. I am not saying the USB input is "good enough" (I promise to you I will never use that phrase), but I will say that using the USB input will result in a sound that is on par with similarly priced headphone amps.
Yet when my source components were connected to the M1 HPAP's line input, it resulted in a sound that was better than similarly priced headphone amps. I'm aware that quite a few audiophiles are going to use the USB as their sole input. For those audiophiles it is important that they make sure all things are working in favor of getting the best sound from one's computer, which means (whenever possible) using the highest bit and sample rate possible, plus, making sure the signal is passing through the computer without compromise, such implementing ASIO service, etc. There are many threads and other discussions on the internet that will assist one in setting their computer for optimal audio performance, and I highly recommend one doesn't ignore these suggestions in the name of convenience. I should also mention that I compared the USB input and the line input by switching back and forth between the two. This wasn't easy as it might sound, as connecting and disconnecting cables as well as level matching came into play, and prevented me from making my A/B listening sessions anywhere close to resembling a controlled lab test. Despite this, like I said, I did hear a difference between the two in favor of the line input. But depending on the source you feed the M1 HPAP's line input, results will vary.
I also promised that I would use the M1 HPAP as a preamplifier. I'm not sure how many users will purchase an M1 HPAP to use it in this manner. Nevertheless, the function exists if not only to use the fixed output as a pass-through. I used the M1 HPAP as a preamplifier in two systems, the big rig in my main listening room and the second system in a common space in my home. I was doubtful that the M1 HPAP would have enough gain to drive the large electrostatic speakers in the main room, and I was correct. The Balanced Audio Technologies preamp I normally employ has plenty of gain, but even that component's volume control must be turned to about 75% of maximum to obtain normal serious listening volumes. The M1 HPAP could barely reach background volume levels when its volume was on maximum. Its use in the second system fared much better. In that system two speaker systems that have taken up residency of late. The first, the two-way floor standing EgglestonWorks Isabel are quite easy to drive. The tubed PrimaLuna 6 monoblocks with 70 Wpc have enough power to drive them to almost painful levels without the preamp de jour even breaking a sweat, in fact, some have trouble being set low enough for background listening. The M1 HPAP's volume level was more at home in this system. Surprisingly, it sounded pretty good, too. About a month ago the Venture Encore floorstanding speakers were installed in this room, waiting their turn to go upstairs into the main system. These very pricey speakers didn't embarrass this Musical Fidelity headphone amp too much when used as a preamp during its short audition, but it didn't sound as nearly as good as any of the units that have ever passed through my system that were designed specifically for the task. I'm still not entirely sure as why the M1 HPAP didn't sound as good when used as a preamp as its specifications led me to expect. I suspect that this unit used as a preamplifier might sound better in some systems than it did in mine.
Wrapping Things Up
Ratings: I tend to rate audio components very conservatively. A rating of 5 notes is equal to the best I've ever heard.
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