Greetings mate and Welcome aboard!
Stuart Charles here, HomeStudioBasics.com helping YOU make sound decisions, so…
AKG’s K240M 600 Ohm headphones were first released in 1984-85, and I’ve owned 2 pairs. The first I purchased off of eBay for around $35 shipped, but the seller forgot to mention one of the drivers had malfunctioned. Fortunately, my mom’s husband had one collecting dust in an old cardboard box since about 1988, and he was kind enough to gift it to me.
Sonically, these headphones are similar-ish to the updated K240 Studio version, but the sound isn’t as good per my experience.
While the Studio version is nice and open, with fantastic separation, resolution, and timbre, the K240M sounds muffled and much more closed in by contrast. I’m not sure if this has to do with age, the fact that it’s harder to drive, pad discrepancies (My M version’s pads are worn down a bit more), or some other reason, but the difference is obvious.
It’s entirely possible there could be a loose connection somewhere, but the sound comes through fine with no obstructions so I’m inclined to think it’s just not tuned as well. In thinking about it some more, I think the pads are a pretty huge factor here.
For a headphone made in the ’80s, driver matching is surprisingly good, but the headphones will need more juice from an Amp than you’re probably used to.
If I only need around 24/100 with the K240 Studio for a comfortably loud level, the 600 Ohm M version requires around 44/100 with my DragonFly Red. It’s still not as big of a discrepancy as you may think, and at the end of the day, the M version isn’t that much harder to drive.
In browsing the internet you may think you need a nuclear reactor to power this puppy, but it’s just not the case.
The sound signature is roughly the same: Lots of sub-bass roll-off, a mid-range boost around the presence regions, and a crisp treble absent any sibilance.
The problem here is that the M version simply doesn’t sound as good, and there are some strange, somewhat jarring cuts around the response.
For instance, after 3.5kHz or thereabouts it takes a nosedive and causes everything to sound kind of wonky and distant. This issue doesn’t manifest in the Studio version, which I believe is tuned much better overall.
The bass on both is roughly the same, but the bass quality and articulation of notes sound a lot better on the Studio version.
Treble
The same goes for the treble. On the K240M, it’s overly subdued, lacks sparkle, and sounds dull; almost unaccounted for. The Studio version is again, tuned much better and finds a nice happy medium between overly bright and too dark.
If you’d like a more detailed review of the K240 as it sounds today, click here.
Build and Design
Cosmetically, the headphones are rather similar looking but AKG made a bunch of small changes in the updated version.
They’re both around the same weight, with the K240M coming in at only 5g heavier (245g vs. 240).
They both share the same hammock style adjustment, semi-open design, headband pad, cups, and general shape, but the K240 Studio now utilizes a detachable mini-XLR cable which is an excellent update and much appreciated.
I wish Sony would do this with the 7506, but I digress.
The M Version utilizes the same hilariously long 3m (9.8ft) cable, but it terminates in a 1/4″ jack at the business end rather than the 3.5mm seen in the Studio version.
Fortunately, I have an adapter lying around (seen above), but it’s clear AKG designed the M version for big bulky amps which is totally fine considering their high Impedance and low Sensitivity. More on that in a bit.
The outside of the studio version’s cup reads “AKG” and under that “55 ohms” while the K240M says “600 ohms”, “K240”, “Monitor” (in cursive), and “MADE IN AUSTRIA” in small block letters. Keep in mind the newer Studio version is made in China.
Flipping the headphones around, the M version simply says “AKG” on the right side in addition to their logo, while the K240 Studio’s detachable cable occupies the left side.
Comfort
Comfort is about the same on each, though because I just purchased the K240 Studio, it’s going to be more comfortable over longer sessions until the pads start to wear down.
After this happens, you’ll begin to feel the fabric covering the drivers touching your ears a lot more. While not a dealbreaker, you will likely be adjusting them every so often.
The faux leather padding may also dig into your lobes a bit, and it tends to collect moisture quite easily.
Other than those caveats, comfort is actually quite good overall and this is undoubtedly due to their featherweight profile.
Clamping force is excellent, and because they’re so light, you won’t feel them digging into the top of your melon.
A Final Word On Amplification
This is perhaps the main difference between the 2 headphones.
The 600 Ohm variant is going to resist power quite a bit, and this is why it’s super important to purchase an amp that will provide enough power into that Impedance rating.
55 Ohm
By contrast, the 55 Ohm K240 will not resist too much, but we still have another dilemma on our hands: the misunderstood and dreaded Sensitivity rating.
- Related: What is Sensitivity in Headphones?
If you weren’t aware, Sensitivity is basically a measure of how efficient a headphone is.
The higher the number, the more efficient.
The lower the number, the less efficient.
- Anything over 100dB/mW is very efficient and does not need much power from the amp to reach acceptable listening levels.
- Anything around 97db/mW and lower is not efficient at all and does need more power from the amp to reach acceptable listening levels.
- 98-99 dB/mW is kind of a grey area in my opinion. If you have a headphone with a number like this, take a gander at the Impedance. If it’s a low-ish number as in the case of something like an M40x, you won’t really need an amp.
In the case of the K240, both the M version and S version have an extremely low Sensitivity of around 91dB/mW, but with the 600 Ohm (M), not only does it resist power a lot, but it also requires more from the amp.
Around 79-80mW.
This takes into account both its high impedance and low sensitivity.
Overall, the K240M, while a neat relic of the past, isn’t relevant anymore (at least mine isn’t) and I’d rather you just go with the Studio version as it sounds much better and is more readily available.
Learn More:
Well that’s about it for today my friend! I hope you’ve enjoyed this AKG K240M 600 Ohm Review/comparison to the newer K240 Studio and gained some valuable insight.
Questions? Comments? Requests? Did I miss the mark on something? Please let me know down below or Contact me!!
Do you have any experience with any older K240 models? I would love to hear from you. Until next time..
All the best and God bless,
-Stu
15 comments
Hi! Great review 🙂
I’m an AKG K240 studio 55ohm owner for some time and I love ’em. Which headphone amp would be good with them? I’m looking for a way to get some more punch from them – 2 days ago i’ve connected them to a very old 1970s Philips solid-state amp and the liveliness of drums and bass guitar blew me away.. but the sound was fatiguing my ears after couple of songs. The amp was broken & repaired etc maybe because it’s old the sound is getting distorted i don’t know. So now i’m looking to get that kind of power sound again but without headache 🙂
I’ve been reading some reviews of Schiit Magni vs Topping A30 and here you mentioned another one – JDL Labs O2 but it feels like you recommended it for 600ohm version?
Hey man! I think an Objective 2 or Atom would both be fine with the K240 600 Ohm. To be honest, I got a pretty decent level with the 240 600 Ohm out of a FiiO E10K of all things. Yeah sometimes I think specs are a bit overrated but in no way am I saying that’s the ideal pairing. It just so happens I have an E10K lying around and thought “Why not?” so I tried it and was surprised that it did sound loud enough even despite only pumping 200mW into 32 Ohms. Magni is okay; I used to have a Magni 2 but sold it. It’s not as good as an O2 or Atom. A bit grainier. No experience with the Topping. I would suggest a good DAC + Atom or Objective 2 and you’ll be set for a long time. I would go with Atom because it provides more power and you’ve got a pair of RCA ins and outs as well in case you ever wanted to pair it with some studio monitors. The inputs allow you to use RCA to RCA from another DAC as well, or you could simply use a 3.5 mil interconnect between devices. For instance I paired the Atom with a K3 from FiiO and loved it. Keep me posted!!
Hello there, I own a pair of AKG K240 Austrian made phones. I know that simply plugging them into my Sony 510 processor and trying to listen to my old record albums is not at all the ideal set-up.
I have been looking for a product that will help me to extract the best performance from them. Are you perhaps familiar with any of the products from Schiit Audio?
The JOTUNHEIM in particular is one that I’m considering.
I own their phono preamp called the MANI and I’ve been very satisfied.
Thank you for the article and for the time you put on with these products.
-Eric
Hey man! You’re welcome! I don’t have all that much experience with Schiit products, unfortunately. I used to own a Magni/Modi 2 and ended up selling it once I heard better stuff. That amp was pretty bad when I look back on it. I’ve heard they really improved their product line, so you may have luck with some of the newer stuff. I have an AKG K240M myself! Great headphone. It does need a bit of extra juice. I run it mostly with a K5 Pro. Check out my article on that: Before YOU Buy A K5 Pro, READ THIS!! It has about 1.5W into 32 Ohm. It has a switch with 3 modes. low, middle, and high gain. I’m on the middle gain. I’ve never really needed the third which is one reason I recommend it a lot. It’s just a great product. 🙂 Let me know what you think.
I own an AKG 240 600Omh, and until I’ve paired it with a Lake People Phone Amp G3 Ampligor, I haven’t discovered its potential in musical performance.
Now it has a much more powerful and round bass, an equally smooth, detailed treble, and maintains and expands that magic in the middle. Very musical.
Hey man! Love the K240M 600 Ohm. So glad to hear you’re enjoying them! I’ve heard some things about Lake People and I think I reached out to them awhile back about a demo unit but unfortunately did not hear back. I guess it couldn’t hurt to try again!
The only issue with my K240M was that the guy who sold them to me failed to mention the slight buzz at very low volumes which was fairly irritating. I ended up selling them but would love to have another pair in the future. I also owned the K240S for awhile as well. You’re right though; it’s one of the most musical headphones I’ve ever had the pleasure of owning, which is why it’s in my Budget Kings series. if you ever want to take a gander. 🙂 Hit me up anytime you’d like to talk audio!
Hi!
First of all, love your reviews, congrats and this is another, is another great one!
You say “With a good amp, be prepared to be blown away!”. I have the K240 MkII and I plan to buy an iFi ZEN DAC. Do you this this would be a good DAC/Amp to the 240’s (and the 702/712 I plan to buy later)?
Thanks and keep up the good work!
Hey man thank you so much! Yeah I think you will be fine with the Zen!! Where are you from?
I’ve been using my 240 Monitor 600 ohms for years. As I’ve gotten more and more into mixing and mastering, I’ve recently tried the Sennheiser 6XXs and Beyerdynamic 990 Pros. Both were so uncomfortable that I sent them right back. The clamping pressure was too much. Yes, I wear glasses and, yes, maybe I’m overly sensitive, and yes, maybe I could have bent them (as I see on Youtube), but I don’t think I should have to do this to get a comfortable headphone. Sadly, I was never able to give them a good workout as a studio headphone. So it’s back to my good ol’ 240 M’s. Bottom line is: get to know your headphones and they’ll work just fine.
Hey Greg! I’m really saddened to hear that about your 6XX! Please give it another chance! LOL. I’ve had my HD600’s since 2016 and couldn’t imagine life without them. They do open up over time, and yeah, the clamp is an issue at first. I happen to really love the snug fit of them because it feels like receiving a warm hug from an old friend, lol.
I do think you bring up a great point though, and that is: people are rarely satisfied with what they have and that’s certainly a huge problem in audio. They’re always looking for the next best thing; their next “fix”, but in reality, diminishing returns kicks in at around the $300-400 mark and there are few products above that threshold that are really worth the price. Yes, the audio improves, but at what cost? At that point, you’re basically mortgaging your life savings for an extra 1-3% increase in sound quality.
If the DT990Pro was clamping too hard, try the consumer version. According to Beyerdynamic, they’re the same headphone, but the consumer one has less clamping.
I’m using a EMOTIVA Basx A 100.
Check it out, my cans are EKG 600 OHM.
Nice!
I don’t know if my message will yet reach you in 2024.
I bought my AKG K240 from Austria in 1991, yes 33 years ago!
On this very moment I repaired it because it was fallen and damaged.
Its is working again very very well!
I have experienced more then 10 other headphones but none of them gives me the sound that I admire so much!
Even now I listen to very beautiful music and I really do enjoy it with my old AKG as never before!
Cheers from The Netherlands!
Peter,
Great to hear from you! Yeah, the K240 will always hold a special place in my heart. It’s perhaps the most unique sound signature I’ve ever heard, and still holds up today! In fact, I have it in my Budget Kings Series because of all that plus it sounds absolutely incredible with older Motown, Rock, etc. The resolution of the K2409 is something all companies (especially consumer grade) should take note of and learn from. Tuning is also excellent though I will admit there could be a little more bass. But, the mid-range? Some of the best mids you’ll ever hear! What other headphones do you have and what Amp do you run them out of?
Hope to chat again,
-Stu