The Portaphile 627 is a class A amp that has been crafted around a shoebox design. Much like the Dynaco ST-35 was for the high-torque shoebox designed 60’s amps so the Potaphile 627 is for modern portable amps. Though not quite as petit as some of the other designs in current production this amp allows the use (and sonic enjoyment) of both IEMs and full-sized cans, making it a true performer. Cesar Aguilera currently operates the company out of the Rio Grande valley in Texas and is a pleasure to do business with. Out of my six or so emails Cesar was able to respond in less than two hours to each, quite a feat considering he’s balancing a soldering iron in one hand and a keyboard in the other. I would also like to thank Average_Joe for the time that he has put into his Amplifier, Cable, and Custom IEM reviews, as it is a boon of information for our community. Paralleling this sentiment, previous to Average_Joe’s review of this portable amp I was unaware, as I’m sure a good many of us were, of the 627’s existence. The marketing giants here sometimes overrun great products on HeadFi and Average_joe’s review undertakings have been a warranted breath of fresh air for some of these less mainstream products.
Preparing the Portaphile 627 and Listening “Rules”
I have burned the amplifier in for about 200 hours and I believe that will be sufficient for the review. Two different approaches will be taken during the review process to give a more holistic approach with regards to the amplifier’s sound. First I will test both my custom IEM and full-sized HP with the line out of a sixth generation iPod. The majority of users, including myself, will be listening in this fashion and so I’m obliged to review it as such. However, I also feel that it is important to put some real juice behind the amp by connecting it to my main system. This way prospective buyers can get a taste of how the amplifier performs when connected to a moderate source and how the amplifier scales its performance when connected to high-end source.
Equipment Used in Review
As mentioned above I will initially use my sixth generation iPod, which has not been modded in any manner. The line out cable is your run of the mill cable, which unfortunately means that it is not overbuilt for any audiophile application. My custom set of IEMs are the Dream Earz Aud-5X, if you are unfamiliar with these Average_Joe and Nulliverse have reviews out on headfi that you may reference. For the full-sized review I will be using Sennheiser HD-650s with the stock headphone cable (modded with banana plugs for use with speaker amplifiers). When connecting the Portaphile to my main system it will be feeding on a much better transmission line than that out the iPod, which will hopefully allow for an improved sound. From the ground up the system is, Sonos, Synthesis Matrix 24 bit Tube DAC, DejaVu Audio custom 6SN7 preamp, McCurdy AM-405 tube amplifier. I mention the amplifier because I currently use it for both my speakers and full-sized cans as it only outputs about 5 watts per channel. Briefly, it is an input transformer amplifier from Canada that was used in radio studios during the late 1940s and is a dual mono design with two Telefunken EL84s and Sylvania 6AU6s per side. My SPDIF cable from the Sonos is an XLO LE-4 reference cable, all RCAs are Audio Note AN-V silver litz cables, and my y-cable for the portaphile is also an Audio Note AN-V with a 1/8” jack termination. The y-cable will be connected to the output of my preamp and I will control volume via the Portaphile. Since my equipment is tubed I will warm it all up for two hours previous to the review session to insure that everything is sonically ready for a performance.
Portaphile 627 and iPod
I choose to use my iPod because my iPhone 4S seems to pass quite a bit of electronic noise, which is not advantageous to a listening session. The iPod, on the other hand, is dead silent both out of the headphone jack and when connected lineout to the Portaphile. Let me begin by saying that upon initially hearing this combination I was taken aback by its musical presentation. With the Aud-5X this combination is smooth and spacious, leaning toward the warmer side of the range. Straight out of the iPod’s headphone jack the Aud-5X is immensely forgiving of bad recordings but it is accounted for by the sloppy audio reproduction from the iPod’s internal amp. Unobtrusive, but bloated the sound is satisfyingly benign. Contrastingly, when used with the lineout feeding the Portaphile 627 the sound is elevated and natural. A wonderful space is conveyed as the sound is pushed forward to just beyond your eyes and outwards to just beyond your ears. The amplifier’s soundstage is akin to a football being placed three quarters inside your head, the two ends an inch forward of each ear and the front curve just in front of your face.
The sound is very strong, as I find most opamp-based units are. Each musical region is confidently represented like a well-seasoned vocalist would perform onstage as compared to a less self-assured amateur. The bass of the 627 is absolutely perfect. It carries a wonderful sense of weight without becoming muddy and really blooms against the amp’s black background. Mids are very nice, but out of the iPod tend to come across a bit bright. Holographic, yes, but they are a little bright. Still they manage a smooth and unfatiguing presentation. Highs are present and extended a tad more than I would have liked, but the hardcore high fans will relish its falsetto sparkle. Again I feel that the iPod does not do the 627 justice here and renders the highs sweet, but weightless. They float within the music like sawdust caught in a ray of sun instead gently thrumming your eardrum like a humming bird’s wing beats. The entire spectrum is quite balanced and definitely adds to the enjoyment. The amplifier is admirably 3D, as I will discuss later, but with this setup that trait is much less prevalent. Much of the 627’s wonderful qualities are shaded by the mediocre source when compared to its performance out of my main system.
My impressions were very similar when using the HD-650s. With the gain switch flipped up (7db gain up, 2db gain down) the amp easily powered the 650s to surprisingly remarkable levels. After the Aud-5X in this combination, I didn’t think the amp would quite be able to step up to the plate with a more demanding set of phones. Cesar says that he tests the amplifier with Earsonics SM3s and Sennheiser HD600s and the latter definitely shows. The sound is rich and powerful although a tad bright, which I still feel is the iPod’s doing. Dynamics are wonderfully lush and it is the real sense of authoritative power that is effortlessly conveyed through each note that grabs my attention. My only real gripe here is that the lows, mids, and highs tend to come across a bit separated almost like a speaker where the drivers aren’t placed close enough together for a coherent sound. The soundstage and instrument placement are conveyed in a very real sense, much more so than I would have thought capable from this combination. I can honestly say that I would be happy with this combination if I did not have my main system to compare it to. It does not seem that the 627 is lacking any power nor does it seem that the phones want anything more than what the iPod and 627 are feeding them. Smooth, refined, powerful…just how these phones should sound.
Portaphile and Main System
Lets start with the 650s as they left a sweet taste in my ears during the previous session. Still using the 7db gain the sound out of the Portaphile 627 is just shy of spectacular (bear in mind this is a portable amp within the context of a full scale amplifier). For a quick comparison, I am upgrading a Woo Audio 3 for a friend of mine and even with my mods it is bested by the Portaphile. Woo products tend to be quite thin sounding IMO, which the Portaphile is certainly not. The sound signature no longer comes through a bit bright but cascades with the energy of a summer rainstorm. It is wet, emotional, and weighty. My only complaint would be too much pronunciation on the top end; it can become a tad shrill where the Woo and especially the McCurdy do not exhibit this characteristic. The soundstage (for both headphones) becomes and oversized football with instrument placement akin to an all-star quarterback’s precision passes. What I enjoy most is the elevated power and clarity the amplifier exhibits when paired with a much more mature source. Every sound comes through cleanly and confidently. It is not cold and clinical, a sound that unfortunately plagues the majority of modern solid-state equipment, but warm and tonally organic. 3D representation is uncanny with a huge voice permeating the center of the soundstage and instruments misted about the rest of the scene. Where I was previously knocking the amp for presenting the lows, mids, and highs like separate entities they now blush like hormonal teenagers and readily fill in the gaps that had previously led to a fragmented sound. Notes are thick and weighty giving the music a feel to compliment the sound. I would still like the highs to have more weight and less articulation, but it is a small tradeoff for the otherwise spectacular sound. When the 650s are plugged into the McCurdy the Portaphile comes close but is thin in comparison. The McCurdy’s tone also beats out the Portaphile but not by a huge margin. The 627 comes impressively close to the McCurdy’s sound but ultimately cannot compete with the rich, euphoric, velvety sound of the old iron. Honestly, I definitely prefer the McCurdy to the Portaphile but it is also ten times the price. For a portable amplifier to come this close I’m absolutely flabbergasted.
With the Aud-5X I am equally impressed with the main system backing the Portaphile and in some areas even more so than I was with the 650s. The soundstage is massive! I’m not the biggest fan of embellishing my text with errant punctuation so that exclamation mark is a testament of my enjoyment. I find that these phones are just a touch bright in the treble inherently, but somehow they’ve managed to be much less so with this combination. Most of what changed for the 650s has equally transformed for these customs as the sound goes from powerful and clean to organic and rich. The midrange is one of the most tonally correct representations I’ve heard from a portable and although it isn’t quite on par with the McCurdy it is deeply satisfying.
This amplifier is a bargain at $550 plus shipping as it is equally adept at powering IEMs on the go and demanding over-the-ear headphones. I find that few portable amps exhibit such prowess in these categories and I’m floored at the extent to which the 627 excels in this respect. If you do not have a dedicated desktop amplifier I would certainly recommend trying this one beforehand or, in some cases, even as a replacement. To be very critical my only qualms with the amp are the slightly bright highs. Take this with a grain of salt though as my main rig rolls off around 17k and I’m coming from an older tube sound. Design wise the amp is great and the volume pot is not nearly as obtrusive as I would have thought. It sticks out a bit but I don’t find this to be a problem ergonomically. The light can be very bright if you are trying to do a night listening session as well. Lastly, I question the analogue volume pot choice as I feel a stepped attenuator would have been more precise than a carbon wiper but that is a very small complaint. Cesar’s comments here that he was unable to find an analogue stepped pot that would fit in the case, so if you know of one he’d be glad to hear from you. Bottom line is; the amplifier is a fabulous example of an intelligent design diligently executed for world class sound.
Edited by colinharding - 10/17/12 at 9:23pm