A Review of the Meridian Prime Headphone AmplifierNovember 21st, 2013
IntroductionA couple of years ago, it might have seemed very improbable that Meridian would send a pre-release product to a member of the HH forum and ask them to review it, but here we are: it's happened. This is very much the result of on-going relationship-building behind the scenes by the HH forum ownership and senior staff at Meridian HQ.
The idea for this review came up during recent HH-Meridian discussions. Timing was fortuitous: the product was in the final stages of pre-production and was pretty much ready to go. Somebody had to endure the burden of listening to Meridian�s latest Personal Audio product � one with no small amount of direct personal input from Bob Stuart (so no pressure) � and that lucky somebody was me. I suppose that posting far too often on the forum counts for something; I knew all those �+1" posts would come in handy one day...
The Meridian Prime Headphone Amplifier was described to me as a nostalgic, even �retro" product � indeed, at its heart is a pure analogue headphone amp (the entire digital section is turned off if there is no USB connection) � and I could sense a great deal of pride from those I spoke to at Meridian who had been involved in its development. However, the Prime also features some very un-retro features: an asynchronous USB input (like its Explorer and Director siblings), DSP up-sampling with apodizing, a DAC, and last, but not least, Analogue Spatial Processing (ASP) to help alleviate the �in your head� headphones experience.
According to Meridian, the Prime has been designed to appeal to the "high performance headphone market". The typical customer in this space apparently uses either high resolution digital files from a USB device and/or an analogue source (often vinyl). This user is also likely to have a separate DAC of their own preference which they use to feed analogue into a headphone amplifier as well as their main system (which explains the presence of the analogue outputs on the back of the Prime). Why a dynamic headphone amp? Well, I�m guessing that the amplification market for ultra-high-end electrostatic headphones is just too fragmented for a single product and the market for dynamic headphone amps is simply bigger.
For this review, I was conscious that, although I own a pair of very good dynamic headphones (Sennheiser HD600s) and listen to them regularly at work via my MacBook Pro and an Explorer, this listening is non-critical, to lossy material via Spotify, and the Explorer does not up-sample and apodize. In other words, I was concerned that when I listened to the Prime at home to lossless material, I didn't have a like-for-like reference point against which to compare the Prime. Further, not having ever listened to ultra-high-end setups (e.g. electrostatic headphones with commensurate amplification), placing the Prime in the sound quality pecking order would be impossible. In the end though, I just decided to listen to as much music as I could through the Prime and report my findings.
In the back of my mind, I was also comparing the Prime + HD600s to my wonderful and very revealing (ID40 + 861v4 w/LPSU + DSP6000) main system. I was in for a shock.
Please note that all requisite Pink Floyd was listened to during the course of this review.
Out-of-the-box impressionsThe Prime is a lovely little unit, an Allen Boothroyd design finished in the silver of the G Series that Meridian has used for a number of recent products; it�s a look and finish that I�m rather partial to, having owned and cherished a silver G68 for many years. The unit feels very solid, although it isn�t especially heavy, and its footprint is slightly less than that of a Mac Mini. Hold that thought...
Operating the Prime is simplicity itself. There�s a power button on the left which, when held down, toggles the rear analogue outputs (its LED turns from white to green when they are turned off), an input selector button and a similar button to cycle through the three ASP modes (Off, i, ii).
There are LEDs to indicate the selected source, the ASP mode and the incoming sample rate (1x, 2x or 4x) on the USB input. Intriguingly, there is a fourth LED to the immediate right of the 4x LED which Meridian tells me is reserved for �future enhancements�. Speculating wildly, I would say that the Prime is software upgradable and that this LED might be used to indicate a firmware upload� Unfortunately, like a number of other Meridian products, these LEDs are, I think, too bright; when listening at night with subdued lighting, I found the front panel rather dazzling. I hope that Meridian can take a look at this and reduce the intensity of these LEDs in production units.
Note that there
isn't a USB cable in the box; I suspect that the target audience prefers USB cables with platinum-plutonium alloys.
Finally, the Prime has a 100% analogue volume knob shaped just like the F80�s (digital) volume control; it has a satisfying �weight� to it.
Listening setupThe vast majority of my listening was with my MacBook Pro and AccuratelyRipped CDs. Initially, I chose to use Control:Mac as a Sooloos zone even though this had the disadvantage of having to change the Mac�s Audio MIDI setting manually whenever I listened to anything with a different sample rate (e.g. DVD-A rips). Setting up the Prime really was a case of plug and play: I connected it to the Mac via a USB cable, plugged in the Prime�s power supply (an external brick) and headphones and, as most of my listening was going to be to RBCD rips, I set the Mac�s Audio MIDI output to 44.1kHz to prevent it re-sampling. Obviously, I wanted the Prime to up-sample and apodize. I listened with the analogue outputs turned off at all times; I doubt there were any sonic benefits, but I preferred the green power light to white.
It�s worth a quick note on my HD600 headphones: they are very neutral and highly detailed, so much so that over a decade on, they are still regarded as a reference class monitor for recording studios and were given Stereophile Class A status in their day. They are, I think, a very appropriate partner for the Prime. For those that are interested, HD600 reviews are available by
Sound On Sound and by
Stereophile. During my listening, I never encountered any reason to think that the HD600s weren�t being well driven by the Prime. I seldom listened beyond eleven o�clock on the volume knob which, considering it goes round to about half past five, indicates quite a bit of headroom.
Analogue Spatial ProcessingIt�s worth talking about Meridian�s latest "special sauce" before I head into my discussion of the Prime�s audio quality. According to Meridian:
Most stereo recordings are mixed with the intention of playback over two separated loudspeakers. When we listen to loudspeakers our ears do not solely or directly receive the left and right channels of the recording. Instead, just as with live sounds, each of our ears, to differing extents, hears a mixture of all the sound in the room. So, in a stereo recording, the ear further from a loudspeaker (e.g. right ear in relation to the left speaker and vice-versa) receives its sound slightly later than the nearer ear and the sound is also shadowed by the head, causing a roll-off of higher-frequencies.
When we listen with headphones, simply playing the recording directly so that the left speaker signal is fed to the left ear and vice-versa can often be unnatural. The impression depends on the recording, but the impression is often that there is too much separation; that sounds happen close to each ear and the sound image feels 'in the head�.
The Analogue Spatial Processing (ASP) built into Meridian Prime Headphone amplifier provides two carefully designed options which blend the left and right signals so as to emulate listening to loudspeakers. The controls labelled i and ii both provide blend but with progressively increasing amounts of delay, representing different loudspeaker angles. The Off function is a pure bypass and the left and right are fed directly with no crosstalk. We find this processing very natural and it can move the image out of the head and enable more coherent sound. You should experiment with the choices on different types of recording.�This is also known as
cross-feeding: it�s not a new concept and I believe that other high end headphone amps also implement it. As far as the Prime is concerned, Meridian chose to implement this cross-feeding in the analogue domain which means that it works with all inputs and, critically, when the digital section is turned off. Naturally, Meridian used its in-depth knowledge of psycho-acoustics to implement ASP.
So, does it work? Yes.
Is it any good? Yes, frankly it�s brilliant. I can�t really describe it in any way other than that stating that it does exactly what it says on the tin. Pretty much everything I tried sounded more natural and listenable. It makes you realize that headphones listening has probably been wrong since its inception!
In general, superb results are achieved with centrally mixed vocals. I found it also works incredibly well with Art Pepper�s "You�d Be So Nice to Come Home To� on the "Art Pepper Meets The Rhythm Section� 176kHz DVD-A (
as recommended by Bob Stuart). Aside from being an outstanding recording of excellent jazz, this album is particularly interesting as it�s mixed straight left/right, with Pepper�s alto sax on the left channel and Miles Davis� �Rhythm Section� on the right. If I�m honest, it�s a pretty uncomfortable vanilla listen with headphones, but ASP made the world of difference! I�d go so far as saying that it made the track listenable.
Throughout my sessions, I had ASP turned on. I played around with both ASP modes. To me, i often seemed to do �more� than ii, but it really is material dependent. Most of the time I just left it on i.
Listening sessions (RBCD via Mac @44.1k and Prime USB input)For me, the Prime is about the very best facets of headphone listening: clarity and detail; but I�d add to that �discovery�. I lost count of the number of times I was drawn to something on a track that I�d not heard before or heard the song in a new light. This often happens when you upgrade your system, but here it was happening with every other track. The Prime + HD600 combo has also made me listen to and appreciate many subtleties and effects used in production that I never knew existed on familiar songs.
My auditioning threw up surprise after surprise. For instance, I was knocked out by the clarity and weight of Chris Martin�s vocal on Coldplay�s "Fix You". I had not expected that.
Jimi Hendrix�s "Little Wing" (remastered) is nothing short of an audiophile dream. The remastering is superb and the production is very complex with lots going on everywhere to good effect. Such a shame it�s only 2:27 long!
The vocal mix on Bowie�s "Space Oddity" is both interesting and effective � not something I�d noticed with loudspeakers where the two vocals on the left and right channels have always seemed to blur. Through a top notch headphone setup, it�s blatantly obvious! Of course, I'll never not notice it again when I listen with speakers. [Wonders how many people will go and dig out this track]
Bob Marley�s "Buffalo Soldier" is a richly produced musical experience with so much more going on than the fairly one-dimensional song that I had a mental recollection of.
On the other hand, Dire Straits� "Private Investigations" threw up no surprises; it�s a fairly simple production and there was nothing more to reveal; it�s still a beautiful track though.
It was also no surprise that Johnny Cash�s vocals on his cover of "Personal Jesus� were rich and brought to life.
On Pulp�s "Disco 2000�, I could hear ludicrous levels of detail within the percussion during the verses and main riff (a high airy percussive effect that I�d previously missed) and the track retained a lot of its foot-tapping factor.
The Prime coped very nicely with the weighty bass on Eminem's "Without Me�. I also heard some of the advertised explicit lyrics for the first time which, frankly, I�m glad aren�t obviously intelligible!
At the end of one of my listening sessions, I added Robert Palmer�s "Johnny and Mary" to my Sooloos playlist to see how it fared. It�s a seminal track, but if I�m honest about it, is a little monotonous and I wondered what the Prime would do with it. Well it came to life. Within moments of the opening beats, the main synth kicks in and I was utterly astonished to hear an obvious �underwater� modulation in the synth waveform that I�d never realized was there.
Was everything perfect? Of course not. Unsurprisingly, I found that even high-end headphone listening simply can�t deliver the emotion of certain types of performance that high-end full-range speakers can. For instance, as a saxophone player, I find the top-to-bottom realism of Art Pepper�s alto sax in "You�d Be So Nice to Come Home To" (Audio MIDI set to 176kHz) utterly convincing via my DSP6000s, but somewhat lacking through headphones. Ditto Gary Moore's guitar solos on his "Still Got the Blues� album. You need to �feel� these instruments and types of performances and you�re not going to do so with a pair of cans.
In general, rock tracks suffer. Probably no surprises there: "Born to Run" is never going to raise the hairs on the back of your neck via headphones the way it does on mine at, ahem, �appropriate" loudspeaker volume. I suspect that Bronsky Beat�s "Smalltown Boy� is in the same category; it just didn�t have the impact or poignancy. I wonder if the synth on this track, like saxophone,
needs more conventional speaker reproduction?
However, in spite of this, I still enjoyed discovering the subtle aspects of this music that would normally be overpowered, and rock/pop tracks with prominently mixed vocals generally work really well with the ASP and sound fantastically clear.
Some tracks were disappointing via headphones:
It�s one of music�s sad facts that "The John Lennon Collection" contains so many abysmal recordings of so many wonderful songs. The Prime showed these up as they are. I�d be interested to know if John Lennon�s original albums fare any better.
The Prime also showed up the excessive amount of reverb added to Nina Simone�s vocal on "Here Comes the Sun�. To bring some balance to this comment, it was clear to me that PJ Harvey�s �To Bring You My Love� has deliberate distortion added to the vocal which works very well through headphones, bringing the intended edginess to the song.
Finally, as an experiment, I did do a sample rate A-B with "You'd Be So Good to Come Home To" on the Art Pepper DVD-A. You'd possibly not notice the downsampling to 44k if you didn't have the 176k for comparison, but there is a difference and the native 176k is just "cleaner" for want of a better word, and very nice indeed.
If this was a song, this section would be the bridgeI want to address two obvious objections to this product which will undoubtedly already be in many HH minds:
1. Why is there no balanced XLR analogue connectivity?
This is quite easy to answer. Meridian told me that there is no point slapping XLR connectors on to a unit unless the amplifier is a dual differential design (which it isn�t). If it was, it would require double the number of components, end up being twice the size and more like a G02 with headphone sockets than something suitable for use on a desktop next to a PC; and it would have cost twice the price�
2. Why does the Prime not have either a Sooloos endpoint integrated into it or a SpeakerLink/SPDIF input?
Not so easy, this one. When my review unit arrived, I was disappointed initially with the connectivity and was convinced that Meridian had made a mistake of omission. To me, it seemed wholly objectionable to put a digital section into the Prime and not have adequate digital connectivity for other Meridian components (e.g. an MS200).
But I�ve done a U-turn here.
The Prime is not a product which is aimed at existing Meridian users, and therein I think lies the problem: we Meridian aficionados have been brainwashed
into believing in and wanting digital connectivity everywhere. In fact, the Prime is best thought of as a pure analogue headphone amp which happens to have an asynchronous USB input, up-sampling DSP and a DAC thrown in for an important use case.
However, with any digital input � USB or other that Meridian might have added to the Prime � one is always going to be limited by the quality of the DAC inside the box. Given the form-factor and cost design constraints, the digital section (from USB to analogue) in the Prime
cannot be (and isn�t) in the same league as, say, the 818v2. Meridian feels that the analogue output from the Prime�s USB input is better than that from the Director. (The components inside are actually similar to those in the Explorer, but the overall package delivers much higher quality.) Not having heard the Director, I can�t comment, but as I�ve already described, the sound quality via the Prime�s USB input is excellent.
Further, as the digital section is turned off completely when there is no USB cable attached, there are additional benefits to be had when using the Prime in all-analogue mode. I can�t quantify the improvement in sound quality, but the lack of digital inside a box with delicate analogue electronics is bound to be helpful.
In some ways, I wish that the Prime
didn't have the digital section, was cheaper, and was available perhaps in a bundle with the Director. I think this might remove some confusion and doubt as to the Prime�s true nature. It would also force the �existing Meridian customer� to think about and choose which
analogue source to use with the Prime as a first step, rather than look on the back for an RJ45 socket and grumble when one isn�t there.
These thoughts brought me to the realization that I would achieve the best results with the Prime by eschewing digital (in the Prime) and feeding it the best quality analogue source I had available.
This is why SpeakerLink or SPDIF inputs, however �desirable", are unnecessary on the Prime.
Having finally got my mind into a 1970s paradigm (LOL to self), it would have been remiss of me not to have listened to the Prime as a pure analogue headphone amp. To do this I needed to rig up an analogue source ideally of comparable or better quality than that already inside the Prime. I considered using my Logitech Transporter as a (high quality) DAC, feeding it the main digital L/R feed that normally goes from my 861v4 to my DSP6000s, but talking to Meridian, I soon discovered that with the 861 (v4 at least), in a digital speaker setup, the main L/R channels are output at unity gain on an un-configured 861 analogue output card. Perfect! Having such a card installed (an OA03), all I had to do was to connect it to the Prime, turn off all my speakers, select the ID40 as source and the Direct DSP preset. I then had a
very high quality analogue source feeding the Prime�s analogue section.
Listening sessions (861v4/LPSU/ID40 via OA03 and Prime analogue input)I confess that I'm very sceptical when I read reports of amazing improvements based on a single listening session. I cannot say if I was in the �listening zone� or not, but I was astounded by the results. These are the improvements that I think I heard over the Prime�s USB input and a few other notes from the session:
On �Skinny Love� I could hear the subtlest of breathing around the microphone and Birdy's lips opening prior to singing.
Duffy's voice was never clearer and softer on "Warwick Avenue", yet still with all its power.
Harmonies from The Beatles' "If I Fell� were so clearly separated. This track sounded really beautiful.
Subtle production effects: percussive electric guitar strings, L/R vocal effects, and keyboards were apparent on Carole King�s �It's Too Late�.
The clarity and stability of vibrato in Karen Carpenters (gorgeous) voice was a joy to listen to on �Rainy Days and Mondays�.
Hidden harmonies were revealed on Everything But The Girl�s "The Road�.
Gerry O�Connor�s "Bag of Spuds� (some of the best recorded and played banjo you will ever hear) never sounded finer. Again, the separation of overlaid tracks is extraordinary.
On "Baby I�m a Fool�, I could hear every finger slide on the guitar strings, and Melody Gardot's voice is simply sensational.
Sunshine on Leith: Isn�t it just one of the most beautiful songs ever recorded?
I've never heard or listened to Richard Thompson's vocal and guitar so clearly on "Vincent Black Lightning 1952".
Ditto the rasp of Stu Matthewman's opening tenor sax on Sade's "Smooth Operator".
On Murder on the Dancefloor, I could hear the nuances of Sophie Ellis Bextor�s accent more clearly than ever.
And finally, a special mention for Paul Simon's original acoustic demo of "The Late Great Johnny Ace" which is just fantastic. There�s a reason why they included it on the re-mastered version of �Hearts and Bones�...
I could go on. This was definitely a "Meridian moment".
ConclusionsWith the exception of the Art Pepper track, all the listening comments in this review relate to red book CD, up-sampled in either the Prime or my 861. I know I�m preaching to the converted on this forum, but it is worth reflecting every now and then on the progress that Meridian (in particular) has made with RBCD in the last decade. What has impressed me the most with Meridian�s apodizing filter is the lack of harshness or stridency on anything that has been half-decently recorded. Tracks on which you might expect something to go wrong in this area such as Duffy�s vocal on "Warwick Avenue" pass with flying colours. I�ve recognized this in my main system for some time now, but what I find truly amazing is hearing yet more details that, for the life of me, I can�t believe made it on to the recordings. Am I simply regurgitating Bob Stuart's comments when I say that Meridian systems are now able to reveal the quietest of sounds by silencing the silence itself?
Up until a couple of years ago, I didn�t listen to headphones that much which, with hindsight, seems a bit bonkers. Given the problems that many of us have in our houses with main system �volume�, high-end headphones would seem to be the obvious solution: their very nature (not noisy) gives them huge WAF. I suspect that I've not gone down this route because I've always felt it would be a compromise (let�s face it, headphones aren�t loudspeakers) and that mentally, I choose to spend my hi-fi pounds on my main system. My experience with the Prime has me questioning that decision.
Your not inconsiderable outlay buys you very high quality up-sampling DSP, DAC and analogue amplification and processing components, and delivers them in a simple, easy to use, package which can be upgraded with the Prime PSU (which I didn�t have to test, but would be willing to
).
I�m not the high-end headphone user that the Prime is targeted at; or maybe I am, but just haven�t realized it yet? Whilst part of me would still love the Prime to have a built-in Sooloos endpoint with wi-fi (!), I accept the engineering and cost constraints and do �get� this product. The sound quality via the USB input is very very good, but going all-analogue via the 861 really shows how transparent the Prime actually is. It is more than capable of working with such high quality revealing sources. (As an aside, this use case has justified my originally aspirational upgrade from G68ADV to 861v4 and hanging on to the unused OA03 card.)
I�ve been very blessed recently in terms of the quality of audio reproduction in my home and have been thoroughly enjoying discovering new music and old favourites alike. My DSP6000s are very special, but to my surprise, the Prime offered me something extra and something new: the ability to discover the finest nuances of my music that, simply down to their nature, loudspeakers of any calibre would struggle to reveal.
Analogue Signal Processing, the latest piece of psycho-acoustically-informed genius from Huntingdon is, in my opinion, worth at least half the list of price of the Prime on its own. It bridges the gap to natural loudspeaker listening without compromising the strengths (detail, clarity) of a high-end headphone setup. In fact, if Meridian is able to re-program the Prime to pass through the ASP processing on its analogue phono outputs, I reckon that, balanced analogue connectivity notwithstanding, some ultra-high-end headphone users with money-no-object electrostatic setups could well be convinced to drop �2000 on the Prime + PSU just for the ASP processing alone...
Whilst I am a confirmed Meridian fan, I think I�ve also been very critical of Meridian where I�ve felt that criticism is warranted. I�m aware that I�ve used a lot of superlatives in this review, something I didn�t really want to do when I signed up to it for fear of opening myself up to accusations of bias; but what this system can deliver by itself, with a high quality analogue source, and particularly with RBCD has to be heard to be believed. I�ll nail another superlative to the mast and say that, when fed by ID40 and 861v4, the Prime delivered the most detail and highest levels of separation I�ve ever heard in reproduced music.
Yes, a pair of top-of-the-range Staxes might best the Prime and any dynamic headphone you pair with it; at a price. Ultimately, I�m judging the Prime on its ability to put a smile on my face; and like most of the other Meridian equipment that I�m privileged to own, it does that in spades. I am not looking forward to packing it up and sending it back to Huntingdon; and I need to start saving.
PositivesGood looks and form factor.
Easy to set up and use.
Hugely revealing of RBCD detail via its async. USB input.
Tremendously transparent analogue section good enough to justify partnering with very high quality analogue sources.
ASP offers real value and is anything but a gimmick.
Upgradable with the Prime PSU (not tested).
Price (YMMV).
NegativesFor highest end use with USB sources, is bettered by the 800 series.
The Prime isn't the highest end headphone amp (that could easily place you in $10,000 territory).
Not a balanced design, which might deter some very-high-end users.
LEDs too bright.
Price (YMMV).
Addendum: The Prime as a Sooloos headphone zoneMany HH will be interested in using the Prime as a Sooloos headphone zone, so what are the options bearing in mind you�ll be spending �1200 on the Prime?
Given the connectivity, it boils down to whether or not you have an existing Sooloos endpoint (MS200 or one of Meridian�s more expensive Sooloos devices) with an unused analogue output in the location that you want to listen to your headphones, or a used analogue output that you are happy to re-route through the Prime (which is actually a more functional solution).
808 and 818 owners can use the unbalanced analogue outputs of these units to feed the Prime (if using either XLR or SpeakerLink as primary outputs). When these products are configured with DSP loudspeakers, the analogue outputs remain "live" and fixed at unity gain which is extremely useful. 861 users with ID40 or ID41 and a (spare, un-configured) analogue output card can do something similar. This is good news if you already have Sooloos hardware endpoint.
If you *don�t* already have a Sooloos endpoint in your Prime listening location (pun most definitely intended), you have a choice: buy one and go the (potentially very high quality) analogue route as above, or you can make use of the digital section inside the Prime via connection to a computer running Control:PC or Control:Mac.
Still holding that thought from the top of the review? The Prime sits very nicely atop a Mac Mini, on which you can run Control:Mac, and is a pretty good aesthetic match. A similar (and potentially lower cost) solution would have the Prime sitting on top of a (c.�250) low power Intel NUC PC (various colours available) and using Control:PC as a Sooloos zone. If you just have CD rips, you can set the Windows or Mac output sample rate to 44.1kHz and the solution will work very well.
However, neither Control:PC nor Control:Mac use their respective platform's advanced audio modes (WASAPI or ASIO on Windows, Exclusive Mode on Mac). As a result, neither of these Sooloos software endpoints adjusts the computer's output sample rate to match that of the currently playing track. This makes them both � currently - sub-optimal solutions with Sooloos libraries containing, for instance, both CD and DVD-A rips. In this scenario, unless you are prepared to switch the output sample rate manually
on a per-track basis, undesirable re-sampling will take place on the computer with at least one category of your audio media.
Therefore, I urge Meridian to enhance Control:PC and Control:Mac to achieve native sample rate transfer to its Personal Audio USB devices. This would please all existing Sooloos customers who wish to use Control:x and, given this might encourage additional sales of Meridian USB devices for use within a Sooloos environment, I think this would be a win-win scenario for Meridian and its customers.
This text (except italics) � Joel Silber 2013. No reproduction without permission.
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