The AKG’s K240 model at 600 Ohm is going to resist power A LOT.
This is why it’s super important to purchase an amp that will provide enough power into that Impedance rating.
By contrast, the 55 Ohm AKG 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 it is. The lower the number, the less efficient it is.
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 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 have an extremely low Sensitivity of 91dB/mW, but with the 600 Ohm, not only does it resist power a lot, but it also requires more from the amp.
A double whammy!
Fortunately for you, I’m here to tell you that there are some fantastic options you can go with to power the 600 Ohm K240 with relative ease. You just have to know what you’re looking for.
JDS Labs Objective 2
Enter the 02, a fantastic entry level desktop solution that has no business being $100. Seriously, this thing is worth way more considering it’s power output, extremely clean signal, build quality, and overall sex factor.
Let’s take a look at the specs:
Max Output (33 Ohms): 613 mW
Max Output (150 Ohms): 355 mW
Max Output (600 Ohms): 88 mW
So, we now know that the Objective 2 will provide 88mW into the 600 Ohm K240 which is probably more than enough.
Before we jump to conclusions and decide it’s worthy, let’s take a look at the Sensitivity again.
The HD600’s at 97dB require 20mW to perform optimally. Obviously the K240 is going to require a bit more..
So we’re in luck! The Objective 2 will power the K240 600 Ohm just fine considering it provides 88.
Fortunately for us, this is the exception and not the rule. Most headphones won’t require nearly that much power. You can see that the folks over at AKG are kind of special. 😛
There’s a pleasant quality about this headphone that’s hard to describe. With a good amp, be prepared to be blown away!
The intricacy of the music and the intimate feel that you’ll receive some mind blowing eargasms.
Let’s talk about build..
Build is also roughly the same: It feels like a toy from your local Wal-Mart toy section. No lie.
I had no issues with the build on the K240 Studio that I used, but by and large they are all very lightweight and cheap feeling. There’s no getting around that.
What about comfort?
The hammock style adjustment and light weight means these will rest on your head quite nicely, although the ear cups are kind of shallow and the padding is a very cheap feeling faux leather.
Even with that said, I still think the overall comfort level is above average considering how cheap it all feels.
You won’t have to adjust either too much, so look forward to some semi long listening sessions..
So what’s the final grade?
The K240 overall gets an A- from me.
It’s not a perfect headphone. Build is a bit wonky, bass will be too light and lean for many, and the ear pads are kind of suspect. It feels like they could crack under any type of pressure, kind of like Henry Hill in Goodfellas.
“I wonder about you sometimes Henry.. you may fold under questioning!”
That said, the 55 Ohm Impedance K240 will resist power less than a 600 Ohm. Still, because the Sensitivity of both are the same, you’ll need something like an Objective 2 in order to power them.
Aside from that, the 55 Ohm K240 is no longer manufactured in Austria like the original Sextett 600 Ohm that we’ve been discussing. It’s designed in Austria but manufactured in China.
Some people have taken issue with this but in reality both headphones are about the same build quality wise when it’s all said and done.
If you’re looking for the Sextett 600 Ohm, I’d recommend trying out eBay!
Stu is determined to provide the truth about all things audio, and strives to deliver excellent content to you the reader! In his spare time, he likes to fish, paint, play guitar, attend church, take photos, record videos, graphic design, and more. His attention to detail and perfectionist attitude are what allow him to excel, but it can be both a blessing and a hindrance at times.