AKG K340 Electrostatic-Dynamic Headphones

The original top model from AKG unfortunately weakens on many levels. A pair of headphones can be as great as you like, but if they don't fit properly to the head due to a lack of hinges for horizontal adjustment, or the ear pads are too thin and the ears touch the inner plastic grille, or the suspension headband is too weak, the sound can still be as good as you like - the headphones are put away after 10 minutes. This is exactly what is present with the K340. I have made some modifications to improve the wearing comfort, but I demand that from a manufacturer itself - in 1979 the heads were not different than today (in terms of shape).

I own the model with gray drivers, so it is a "bass heavy" version, while the others (red and black) are also often described as that, or at least as "neutral". The green version is referred as "bass light". My test combination can be seen in my signature.

And yes, the bass is good in quality and quantity, reaching below 40 Hz and producing a pressure that electrostatic drivers could never do on their own. And yes, the electrostatic drivers reproduce a great amount of detail, including fine detail. They are never intrusive, bright or metallic, instead the high frequencies are very pleasant to listen to. Combined together in the AKG K340's cabinet, it sounds like this: As if you actually put good speakers in a laundry room with tiles on the walls. Unlike other models from the time (explicit the K240 Sextett), the K340 are not brightly tuned, also the soundstage is extremly wide and large. However, this combination makes everything sound hollow, synthetic and washed out, as if there was a big veil over everything. Everything sounds wrong, out of phase, not homogeneous in itself, every driver playing separately for itself. After half an hour I had a headache because of this, the brain tries to permanently compensate the obviously audible delay between the electrostatic and dynamic driver.

So the K340 had to be modified. Rewired the entire headphone, the dynamic driver is thus directly connected, a cable from the dynamic driver then leads to the PCB, instead of first to the PCB and then to the dynamic driver. This solved the "out of phase" problems, the sound image is much more homogeneous. Other ear pads also immediately help the headphones in terms of sound as well as comfort. I also removed the inner grille, this made a big difference. For more details feel free to look at my posts.

Connected to a rather darkly tuned OTL tube amp, the slightly modded K340 suddenly becomes great fun. I admit, I was initially very disappointed with the headphones and didn't understand what they did better than a K240. But now I understand what people mean that these headphones can easily compete with today's models. I won't say it's better than the 500€ price range, but it attacks them with its very interesting unique presentation.

When I first began my career, I was looking for some inexpensive but good quality headphones for my personal reference. The K340`s were less expensive than the cream of the crop at that time, the Staxx system with the discrete amp, etc. Over the years I have had no problems with the jack shorting, cord fraying, plastic breaking, etc. They have always been reliable and within the factory specs.  At the time the k340 came about, most of the less expensive headphones had the standard 3 strand wire design that was not well shielded and little separation of the left-right-gnd wires inside the mono outer casement. My K340`s have the molded 4 wire flat cable that provides about .080" separation between the conductors. I have never had problems with crosstalk or noise from the headphone wiring that I can remember. They have held up very well over the years. I have used them as reference head monitors for a number of recording projects from Margo O'Donnell, Dolly Parton, Five Bucks, to the smokey mountain travelers. They remind me of a headphone version of some JBL 4310`s or some good NS-10s. For live, the ear  foam ring does do an ok job with high spl situations during a loud show. They have survived many road shows over the years. I still pack them in the original Styrofoam vendor packaging. They are well used and loved and they have never let me  down. I am surprised that AKG stopped making them years ago, but has continued making the k240 which is the baby. I feel as though I made a decent investment those many years ago. And, if I ever need to, I can send them to Austria for a tune-up. thanks all 

I bought the AKG K340 Electrostat-Dynamic System twice. The first pair was very worn out and sounded weird so I sold them after a while. I bought the second pair from Ebay, and this one sounded very different. I used the first pair with the Beta 22 amp which really struggled to drive it properly. The second pair I'm using with Headroom Ultra Micro Amp with Astrodyne PSU, and surprisingly it drives this pair with no problem, I hardly pass 10 o'clock of volume!
 
I suspect that the second pair is the bass heavy version. There is a lot of bass here with deep impact, although not very detailed but not loose bass like that of D2000/D5000. It's well integrated into the spectrum of sound and adds a lot of warmth to the sound character. 
 
The Mids and Highs are the best quality of this pair. They are very clear, very detailed and very smooth. This is attributed to the double driver system of the K340 (electrostat and dynamic), which eventually results in a very layered sounstage of 3D holographic nature, while on the K702 it feels 2D in comparison.
 
Compared to my beloved K702, the violins and flutes sound very smooth and extended, while on K702 they seem very bright in comparison with slight harshness. If I don't compare the K340 to K702 and keep listening to the K702 I don't feel there is any problem with the highs, they look absolutely OK, but when I put the K340 on, the K702 pales in comparison and sounds gray while the K340 is all black and white. The only area where K702 excels is a wider soundstage (which lacks in depth) and the bass is more detailed but without the impact and warmth of the K340.
 
On listening to DG's marvellous CD "Fiesta" or Boulez excellent recording of Varese's Arcana on Sony, I feel like a real Orchestra is playing on the stage, giving the instruments a great weight and impact that I never felt with the K702. Playing Beethoven's Cello Sonata No.1 by Schiff and Perenyi  I was overwhelmed by the Cello's deep and dark sound, it was a great emotional experience that brought tears to my eyes!
 
On listening to the K340 I only think about the music and the composer who created it, while on listening to the K702 I only think about the good sound quality! 
 
Considering their price range of 150 to 200 those cans are a steal, they can beat HD650, HD600, K702 and even my recabled K400 in performance. They are not perfect but considering the price and value they are a real treasure!

This a great cans , but very hard to drive. Vocals never sounded so clear and articulate, bass is good , but not great.

I normally don't write long or extensive reviews, but this product has really exceeded my expectations!
I recently bought a pair of NOS AKG K340 headphones from a Headfi member in Austria.
Thanks JeckyllAndHyde!
I have been using a borrowed HeadAmp GS-1 amp, until mine arrives from HeadAmp next month, a Harman/Kardon HK3490 receiver, and Marantz CD5003 and CD5001 cd player with them.
I have been listening to a WIDE VARIETY of music, including live, acoustic, classic country, classic rock, pop, r&b, etc., on them.
They are definitely the bass light version.
At first they were thin, bright, with a somewhat constricted headstage, and had almost no bass.
I was rather disappointed.
I then took the stock plastic screens off, and replaced them with some fabric screens that came off my other modded K340's, with a dead driver, and WOW, what a difference this simple mod made!
The bass became deeper and more powerful, the mids and treble openned up, the brightness and thinness almost completely went away, and the soundstage opened up considerably!
The only drawbacks I am hearing from the fabric screens compared to the stock screens is the fact that it seems to takes slightly more volume to get the same sound level, and the lower treble seemed to recess slightly, which really is not a big deal at all to me.
These headphones are truly killer now.
They have the remarkable ability to sound both dynamic, natural, and organic, plus have remarkable speed, openness, clarity, and detail in the mids and treble at the same time!
They sound remarkably like my Paradigm Reference Studio 100 version 2 loudspeakers somehow strapped to my ears! The only real areas where the Paradigms surpass them is in the bass and imaging departments.
The treble, in particular, is outstanding.
The electret element is remarkably fast, clear, detailed, and open, and adds considerable "air", and spaciousness to the sound.
I really hate to admit this but I actually like them better than both my AKG K702 and my Sennheiser HD600 headphones in most areas! This is remarkable considering how old the AKG K340's are.
I feel they have better dynamics, naturalness, openness, spaciousness, and clarity than either of the newer headphones, and overall, the K340's just sound more lifelike than either. The top-end on the 340's is more extended and faster than either the K702 or the HD600, IMHO.
The 600's do have alittle more bass power and extension, and may have a flatter overall frequency response, and better coherence, but the 340 is superior in the other areas I named above.
The K702 rivals the midrange and treble detail of the 340's, and may even be superior in some areas, but the 340's don't have the slight peak in the upper mids/lower treble that the 702's exhibit, and the top-end is superior on the K340, in my opinion. The mids on the K340's are also richer, and seem to have a better, and more accurate tone, than the 702's.
Compared to my Beyerdynamic DT880's that I owned, the 340's are actually similarly balanced, except the 880's are slightly more recessed in the mids. The highs are actually similar, except the 340's top-end sounds slightly faster, and seems to have slightly quicker decay.
Another thing my particular K340's seem to display better than the HD600's, K702's, and DT880's is a sense of a 3-dimensional quality to the sound thats hard to explain or describe exactly, and an uncanny ability to separate instruments, and put air around them.
Another thing I like about my K340's is that different recordings sound alot different as far as equalization goes when they were recorded! I hear differences in the way recordings were mixed and equalized better on the K340's than I hear on the 600, 702, and 880. I can also occasionally hear strengths and flaws in familiar recordings, that I have not noticed as much before on the other headphones.
Are they the perfect headphones? No.
The weaknesses I hear with my K340's are a slight lack of bass power and extension, the electret element doesn't quite blend perfectly with the dynamic driver, and it is noticeably faster than the dynamic driver, which leads to some incoherence between the bass/mids/highs.
I also wish they were alittle more comfortable, and alittle easier to drive.
Needless to say, my K340's are getting considerably more headtime than any of my other headphones, and I love 'em!
I cannot imagine how good a Headphile modded K340 by Larry would sound! 
I may send him a stock pair sometime soon and let him work his magic on them.
I have another stock pair coming in a few days that I will either use for spare parts, or have them modded.
I would absolutely love to see a MODERN implementation of this two-way technology in a new headphone, using a similar electret, planar, or a super fast dynamic driver for the highs, and a ring radiator driver or similar unit for the bass/mids, using modern computer modeling, advanced diaphragm materials, modern magnet systems, and advanced driver housings, etc.
Now that would be something to behold...and hear!

 
It's time for another review that I've been sitting on for a while. Writing a review of a vintage headphone is difficult at the best of times, and there are some strange features of the AKG K340 that are even more difficult to deal with. Nobody is sure whether there are several different runs of the headphones with different sonic signatures. They are notoriously difficult to drive properly, and many of them have now been modded to various extent. All of that in mind, I suppose this will have to be a review of MY K340s. Others will probably be at least somewhat different.
 
I know precious little about the history of my pair. I know someone has been under the hood, because the pleather pads have been replaced with velours, they have been recabled and terminated with a 1/4" Neutrik plug. A quick peek under the pads reveal that the screen mod has been done as well, because there is no plastic mesh between the pads and the driver. The elastics still have a bit of pull as well--enough to keep them relatively stable on my head. These changes have likely made minor changes to the sound.
 
While the K340 is a bit heavy, they sit quite comfortably on my head. I really like the self-adjusting system that AKG has, because I find it keeps the right amount of pressure on the top of the head and the ears. I can wear these for quite a while without them being uncomfortable. The new nylon-covered cable is slightly microphonic, but I don't see that as a huge problem since these are hardly headphones I wear while on the go.
 
All reports about the K340 being hard to drive well should be respected. I am not impressed by the sound I get from them out of most of my sources. They only really shine through my Musical Paradise MP-301 tube amp. For the purposes of this review, I am using FLAC in Foobar bitstreamed into my M-Audio Delta 2496, with RCA cables feeding directly into the MP-301. For those who care, I've got NOS Jan GE tubes in the preamp, and Tung-Sol 6V6GT as amp tubes. It's a good combination with the K340.
 
Now that all that's out of the way, I can get talking about the sound. To be up front right away, these are not my best sounding headphones from a technical standpoint. My DT990/600s dance around them in just about every area, as do my DT150, Kees modded Pro 750s, and maybe even Fostex T50RP.
 
Here's the thing, though. The AKG K340 is a fantastically easy headphone to listen to. They are so musical and so well-rounded that they've gotten quite a bit of head time lately, and never fail to get my feet tapping. They are truly incredible all-rounders, once they are fed the kind of signal they crave.
 
I suspect I have the bass-heavy version, as they have proven time and time again that they are capable of delivering plenty of low-end grunt. Massive Attack's Angel remains my primary bass test track, and while the K340 doesn't dive quite as deep as some of the headphones in my collection, it creates a delightful sense of space at the low end, which doesn't diminish as the rest of the song develops above it. It lacks some of the punch of my Beyerdynamic cans in the low end, and I understand the criticism that some have that the K340 tend to have flabby bass. That softness is emphasized more in Rock and Soul, where the low end has a tendency to get a bit muddled. It's not a deal-breaker, but it is probably the weakest point in the sound. What the bass lacks in tightness, however, it makes up for in quantity. It's very easy to follow bass lines with these headphones.
 
The slightly slower speed of the dynamic drivers persists a bit into the midrange. I can't complain too much, though, because it's all so incredibly musical. Vocals, guitar, and piano all sound spectacular on these headphones. It's what AKG is known for, and they really nail it here. I played a few tracks by Fiona Apple, Jeff Buckley and Sharon Jones to focus on vocals. In each track, the vocals are emphasized nicely, and are emphasized without being too forward. The K340 seems to add very little coloration to the midrange, as some vocals sound warm and cool depending on the source. Overall, the signature is quite warm, though.
 
The treble in the K340, for those who don't know, is handled by an electret driver that functions along with the dynamic driver. This is a bit paradoxical, because while the bass and midrange aren't especially fast, the electret driver delivers lightening quick treble. This is an odd effect in tracks like Angel, because the high end speed exists in opposition to the slightly slower bottom end. It creates an illusion of speed throughout the sound spectrum, and it really is awesome treble. It is fast, bright and sparkly, without ever threatening sibilance or sharpness. It's great for electronic music, but also adds quite a bit to rock music. I could never really get into the sound of the AKG K240M that I had, which was similar through the rest of the spectrum, because of the rolled off highs. The electret driver adds a magical top end to the K340 that makes it much more appealing.
 
The interesting and unique sonic qualities of the K340 has a side benefit that I've quite enjoyed. These are my most forgiving headphones, once they are connected to a good amp. I've been listening to quite a bit of garage rock revival music lately, thanks to the The Like's Release Me, which is a pretty awesome rock record. It's also not that well recorded. This makes it almost impossible for me to listen to the album with the other headphones in my collection. The DT990/600, even on a tube amp, emphasizes the sibilance and becomes quite unpleasant. I don't even want to talk about how this album sounds on the Ultrasone Pro 750. Meanwhile, the Fostex T50RP lacks the raw energy to do justice to the album. It sounds awesome on the K340s, though, because the bass gets a nice boost, the mids are emphasized without getting ugly, and the brightness helps keep the energy going.
 
It's also a sounds that works with a wide range of genres. Jazz sounds pretty good on them too, though things to have a tendency to get a bit mucky. Mingus Big Band's Moanin' sounds awesome on them, though Dave Brubeck's Time Out asks for a bit more clarity and precision. Orchestral music is stunning, revealing a slightly wider soundstage than expected, and an overall dynamic signature.
 
And, in the end, I think that's what the AKG K340 is all about. If you have a tube amp and are looking for a pair of headphones that will be musical, fun, and completely unfatiguing, it would be hard to do any better than tracking down a pair of this unique vintage oddballs. They won't deliver you razor-sharp clarity or studio-use neutrality, but I find myself getting lost in the music, and that's what this hobby is really all about, right?
 
Right.