[Tyson]

Now that I've gotton spoiled with good audio at home, I've been looking for something that will give me similar quality at work, where I get to listen to music via headphones.  Since it's an office environment I am limited to closed (or sealed) headphones, so my Sennheiser HD600's have to stay at home hooked up to my very nice World Audio HD83 tubed headphone amp.  In my search I've come across 2 components that I think are truly remarkable, and are tremendous bang for the buck - the AKG K271 Studio heaphones (which I bought from http://www.djmart.com - $165), and the Xin SuperMini headphone amp (manufacturer direct from http://www.fixup.net - $99 plus about $40 in upgrades/options, total $142).

The 271's are very light and very comfortable, almost as comfortable as the HD600's, and that's saying something!  They have a very cool retro look, black headband, with black pads and black & silver plastic and stainless steel earcups (which are circular and quite large, they fit completely around my ears).  The cord connects on one side and can be disconnected and replaced easily if it ever gets damaged.

The supermini is very aptly named, it's about the size of a pager with a line in on one side and the headphone out on the other end.  It is powered by 3AAA batteries internally, which are supposed to be good for 120 hours of usage.  I'm not sure if that figure is accurate, but I'm at about 40 hours right now and they are still going strong.  

You can get the supermini with either an analogue volume pot or digital volume control.  Looking at how he designed the digital volume control, I decided to go with that as it should give more precise tracking between channels.  The unit also comes with an option called Xin-Feed - it is a crossfeed circuit that supposedly helps give a more natural sound on headphones for music that was mixed to sound good on speakers.  We'll get to my impressions of it below.  

One other option I got was an extra battery power pack that gives the supermini a bit more grunt to draw upon for driving difficult loads like the HD600's impedance of 300 ohms.  For most "normal" headphones its not needed.  But I'm glad I got it, cause it means that my 600's can be portable if I want them to be now.

I'm still running in both since they are brand new (got the supermini yesterday and the AKG 271's the day before that).  But already the sound I'm getting is remarkable.  How good?  Well, I was going to wait another week or 2 to allow the new gear to burn in/break in properly, but I couldn't stand it, so I did some comparisons between the AKG's and my HD600's tonight, both with the SuperMini and w/the World Audio HD83.  I think the AKG's matched up best with the supermini and the 600's matched up best with the hd83.  But they all sounded good, the supermini drove the 600's very well, and the AKGs also sounded very good on the HD83.  

So, did the 600 smoke the AKG?  Well, no, it was actually very close.  The Xin-Feed played a big part in this comparison.  The 600's did not sound as good with the Xin-feed, while the AKG's sounded better with the Xin-feed.  My thoughts are that the 600's, being "open" don't need the xin-feed in order to present a properly spacious and ambiant sound, while the AKGs being "closed" need it to get the ambiance and spaciousness right.

When I fed the 600's the Xin-feed, the mids were too bloated and bass was weak.  On the other hand, without the Xin-Feed, the AKG's midrange was a bit thin and overall they sounded more "closed in".  But even with less than optimal settings, they both headphones still kick the crap our of the HD280's and the Sony V-6's and Etymotic ER6's (and every grado headphone I've ever heard).

But with each headphone set up optimally, I'd say it was actually a tie for sound quality.  The 600's have a slightly richer midrange, and slightly better ambiance, but the AKG's were very close.  And the AKG's had clearly stronger bass that was not muddy at all.  Both headphones have that wonderful combination of palpability and smoothness that makes long listening sessions a joy instead of a trial.  Detail retrieval was excellent on both headphones, and tonal balance was similar, but not exactly the same.  The Senn's slightly favored the mids, and the AKG's slightly favored the bass.  But again, the differences were not large, the end sound was more alike than different.

Since the HD600's MUST have an amp to drive them properly (adding at least another $100 or more to their $350 price), for bang/buck, the AKG/SuperMini with Xin-feed is a killer deal.  Since headphones and headphone amps aren't posted about much around here, I thought I'd share this for others that might be interested.

[Jay S]

I'm starting to travel a lot for work again so I am thinking hard about getting a fully loaded XIN Super Mini.  

It would be nice to find a smaller alternative to the iPOD that still can hold a ton of songs.  I don't need to put my whole music collection on it.

[Tyson]

One more observation on the AKG's and the Supermini - the AKG's have incredibly low sensitivity for headphones, only 91db!  That means that if you try to drive them to very loud levels w/the supermini (or most other headphone amps for that matter), you will get distortion from the amp.  I found that connecting the optional "booster" pack, doubling the power supply, prevented this from happening.  Other headphones like the HD280's, the Sony V-6 or V-7506, all have sensitivity well above 100db, so the AKGs are unusually difficult to drive (for any headphone amp).  If you decide to do the 271/supermini combo, make sure to get the optional battery booster if you want to listen LOUD!  Since I rarely listen LOUD, the battery booster pack is not needed the vast majority of the time.

[Jay S]

Thanks for the heads up on sensitivity.  I will start off using my Sony MDR888 earbuds (which at $50 is/was Sony's top of the line earbud).  The over-ear headphones are too bulky to take on business trips (I don't check in any luggage so everything must be handcarried).

I will order my SuperMini with the optional battery connector so that I can attach a 9v battery or the Booster Pack down the road if I need the extra current to drive a difficult load.

[Tyson]

You can only use a 9v if you get the analoge volume pot, as the digital volume pot is not designed to take that much voltage.

[Tyson]

Wow, only jay is interested in quality portable audio so far?  I'm suprised that more people haven't experimented with quality headphones and quality headphone amps.  

The X-cans are a good amp, the fact that the SuperMini beats it handily is pretty amazing, given it's size/cost.  

Now, the problem of a source, I have a Sony personal CD player (or pcdp for short).  The problem with almost all the recent pcdp's is that 1) they use a compression algorithm to extend battery life (and it cannot be turned of, merely "reduced"), and 2) They rarely have line-out's, only headphone outs.  And even when they do have a line-out, many times the line-out is driven from the headphone output, just split off and given unity gain.  

Lucky for me, there is a player that is readily available on Ebay that has a "true" line out, coming directly from the DAC, with no capacitors in it's signal path at all (woohoo!), the Sony D-FJ401.  This is last year's model, and it has a (supposedly excellent) radio tuner as well built in.  I just won a bid for one on ebay for $39, should be here this week for me to listen to.  It should be better than my current player, which does not have a line out, which means I have to plug the supermini in to the headphone output.

I also got a Bolder Cables mini-to-mini (1/8th inch) cable made from M80 wire.  It made a nice improvement over the generic mini-mini cable I was using before.  He's also making me a replacement cable for the AKG headphones out of a smaller/thinner/more flexible version of the M80 cable, I cannot WAIT to get that bad boy on there

[Tyson]

Of course, if you want "truly" portable, and still very good quality, just swap in a pair of Etymotics ER-6's or ER-4P's instead of the AKG's, these are "canal-phones" that actually fit in your ear canal and are made by a company that makes (as their main business) high end hearing aids.  I have a pair of the ER-6s, and you will not find a smaller pair of high end headphones this good.  The 4P's are better, but also a lot more expensive.

[Jay S]

Yes, you're right re using a 9v battery as a booster.

About the Etys, some reviews have said they have very little bass when used in noisy environments, that the cables are microphonic, etc.  What do you think of the Ety 6?

Will have to check if my portable cdp has a line out or just a headphone jack.  It is about 5 or 6 years old (!!) so maybe it doesn't have the compression algorithm.  I also have a >3 year old MD player.

[Jay S]

By the way, I am also planning on using my IBM laptop as a source!!    Its got both line out and headphone jacks, though who knows if the line out is just driven off the headphone jack.

[Tyson]

The Ety 6's don't have much bass regardless of the environment  I just boost the bass from the player by 1 notch, it fills in nicely.  Lucky for me, on my current player the bass boost does not make the rest of the music sound terrible until you get to the 2nd notch  I've heard other players that destroy the music with any bass boost at all, so matching the Ety's to your source is a good idea.

[BradJudy]

I'm just chiming in to say that you aren't alone in caring about quality headphone sound.  If I used mine more I might spring for better/more equipment (Senn 580s tempt me on occasion), but I have a pair of Grado SR-80s at the office.  I have a battery powered CMOY amp I built at home (not as small as the mini) and a wall powered META42 amp (internal transformer, none of that wall wart stuff for me ) that I also made.  The META42 might get more use once I have my 2-channel system set up at home as there is no headphone output on the integrated amp, but there is a tape out.

[mojoman]

I just ordered a XIN Supermini last week.  I got all the upgrades Tyson has except I opted for the analog pot because I want to be able to use a 9V battery.   I'm looking forward to hearing the mini and comparing it against a portable Meta42 I have that uses AD8620 op amps, stacked buffers and is biased to class A operation.  I like the meta a lot and if this supermini is better, great.  I bought the mini mainly because of it's size.  My current phones are Ety 4S and Alessandro Music Series 2.  Right now I'm using a TDK Mojo 620 as a source.  I use the line out connect with a Zu Pivot.  It sounds ok I guess but I wish someone would make an audiophile pcdp. I've got it all packed into a headroom airbag so I can grab it and go and have some very high quality tunes.  It's also great for late night listening when everyone in the house is asleep.

[Jay S]

Just got my SuperMini a couple of hours ago.  I'm listening to Yahoo! radio right now through my laptop.  I'm using 2 old cables to hook up the SuperMini to the laptop -- a mini jack to a pair of female RCAs, connected to a pair of male RCAs with another mini jack at the other end.  Talk about jury-rigged!  

It seems a little bright right now, compared to listening directly to the headphone output of my IBM Thinkpad, but Xin mentioned that the caps are pretty large and can take up to 3 weeks to burn in.  Also, let's not forgot these jury-rigged cables.  I may get a custom Bolder M-80 with mini plugs on both ends, but I may just get an OFC cable with mini jacks on both ends from the local electronics shop (if it is cheap).  No need to spend on great cables till I start listening to decent sources.

[Whitese]

Anyone try the mimi in ear Stax headphones, with its mini driver..i thinki think its SR001...

[audiojerry]

just to let Tyson know, I've been reading with great interest. Thanks for bringing good stuff to the forum.

[Tyson]

Here is a VERY cool tweak I did to the AKG K271's and also my Sennheiser HD280's.  Tapping on the earcups of the 271's gave a very hollow, plinking type sound - obviously there is not much damping on the "cabinet" of the earcup.  I opened up the headphones, and there's no damping material or acoustic material in there at all.  This can't be allowed to continue!  So, below is a copy of the tweak that I posted over on headfi:

OK, as many may know I've had a pair of AKG K271's for about a month now, after burn in I've been very happy with their overall sound, the frequencey response is very even for a closed headphone, and the dynamics are quite good, and thank god they are not so ridiculously bright like so many other closed headphones. But I've had a number of "small" complaints about their sound, nothing huge, just minor annoyances that would be nice to get rid of, namely the upper/mid bass is a little undefined and the really deep bass tends to come off sounding like midbass (ie the deep bass is not distinct from the midbass). 2nd, the midrange, while forward is a little occluded, not as transparent as I am used to from my Ety's and my HD600's. 3rd, there is a narrow band of brightness at about the 8-10khz range that (besides being slightly irritating) covered up the very high frequencies, causing a loss of ambiance and "space". Lucky for me these all can be fixed with a relatively simple and very cheap tweak.

THE TWEAK:

You will need 3 things to do this tweek - 1. a screwdriver, 2. a packet of BlueTak (the tacky putty used to hang up posters, available at all office supply stores), and 3. three cotton balls.

Step 1:
Remove the pleather earpads from the headphones, you will see 3 screws revealed on the exposed face of each cup.

Step 2:
Remote the screws and pull the cups off - do this VERY gently, the cups are soldered to some very short wires, they will not come off very far. Once you have the cups off and dangling from the wires, you can reach in and pull on the wires, there is a little bit of play in them, and once you pull them out a bit you will have a bit more room to work.

Step 3:
Take the package of BlueTak, and divide it in half. One half is enough to treat one earcup. Take the half and apply it to the interior of the earcup, making sure to keep it at about a 1 millimeter thickness. I found it easiest to pull the bluetak apart in to smaller pieces and apply those pieces one at a time to each part of the earcup in a clockwise pattern.

Step 4:
Take the 3 cotton balls and divide them each in half, giving you 6 pieces total when done pulling them apart. 3 will go in to one earcup, 3 in the other. They are too dense "as-is", so pull them a bit so that they "stretch" a bit, so they are not as dense and they can now cover a wider area. Place the cotton on top of the bluetak (but make sure it doesn't cover any of the screw holes, so you can get the screws in when you go re-attach the drivers).

Step 5:
Re-attach the drivers to the earcups and put the earpads back on. Repeat these steps for the other earcup.

That's it, simple, cheap and pretty easy.

HOW DOES IT SOUND?

Well, the bluetak and cotton soaks up that 8-10khz brighness so you get less brightness, plus the really high frequencies are now very clearly audible, the sense of space and soundstage are greatly enhanced. The midrange is cleaned up very nicely due to the more solid and less resonance earcups. The upper and midbass are still very good, but the deep bass is signifigantly better because the cotton "fools" the drivers in to thinking they are in a much bigger chamber than the earcups actually are, which gives a lower resonant frequency which really gives the low bass some power now.

Overall, this takes the K271's from the realm of "very good" to the realm of "greatness". Not too bad for a $2 tweak  

Now, for the Sennheiser 280's, the steps are exactly the same as above, but there is no room for any cotton, and you don't need it anyway, since the deep bass response on the 280's is crazy good anyway. But the BlueTak definitely smooths out the tipped up upper midrange, so that the mids and highs are now very much in balance with each other. Plus, the added bluetak takes away a bit of the air in the chamber of the earcups, which raises the FS of the bass a bit, so that the bass has more of a boost in the 60hz range, while still keeping its amazing deep bass response.

The net result on the 280's is that you get a very smooth and slightly resessed mids and highs which is VERY musical and very easy to listen to for long periods of time, but you also get a KABLAMO!!! bass response. Very nice, in fact the Senn's improve more than the 271's do, but the 271's are still a far better overall headphone due to their greater tranparency, more balanced sound, and better dynamics and ambiance retrieval after the tweak.

Anyway, let me know what you guys think. All I can say is that I finally found perfect sound with a closed headphone, which I never thought would happen after owning the HD600's. . .