AKG K52 : From $36 to $360 Performance - The Makeover Mods
Apr 4, 2021 at 5:31 AM Thread Starter Post #1 of 8

OspreyAndy

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I love underdogs. Aside from enjoying music and the Audio gears, I am equally passionate with the modifications of Audio gears itself.

And so what I have here is the lowest priced circumaural closed-back 40mm dynamic driver AKG K52. I am sure you have read reviews from those who have listened to them that they are decent enough for a $36 cans. Designated to be a workhorse in the studio for monitoring purpose, assuredly this is the most basic full sized AKG one can ever find. Nondescript black on black and with components almost entirely made of plastic.

Before going any further, it's worthwhile to acknowledge that we all have our own preference of what we consider as good sounding. In particular I am a hardcore Etymotic and STAX self styled zealot, which means I love highly resolving flat neutral sound with touches of sparkly Highs and solid Mids - definitely not a basshead, and I always prefer Closed-Back over Open-Backed. So if this description fits you as well then it may interest you to read further and find out how a $36 AKG transformed into $360 sounding cans. And of course to achieve this you are already handy at mods and soldering.

So how does this AKG K52 sounds like out of the box brand new? Plasticky boxy is how I would describe it. It's just simply artificial sounding for the first 10 hours. But I knew those who vouched for this K52 have good reasons to praise it. Slowly and assuredly the refinement started to seep in. But alas to my ears the tonality was still off, the boxiness remained. Perhaps because she's an AKG, I was half expecting the spaciousness of the famed K701 which I have owned and used extensively.

Pondering on the possible cause for this, decidedly I was convinced the compressed sound were due to the lousy synthetic pads she comes with. So I went online and ordered new pair 103X22mm velour pads from Misodiko, designed for Beyerdynamic DT770.

Initial Stage Mod:
Few days later the pads arrived and I wasted no time putting them on. And tinkered a bit with the idea of Kramer mod pads by making big hole in the middle layer (which I reverted later to fully padded as I find them to be sibilant without any layering).

True enough, just like that the boxed-in compressed tone and staging all gone. Replaced with generous spaciousness I normally associate with open backed cans. This alone has place this K52 well into K501/701 territory despite being closed back. This also mean the Mids are spaced back a step or two, of which I am perfectly fine with considering AKG were never known for being Mids strong. The Misodiko pads also introduced an element which I love the most, dampening of edgy highs which in turn helps with sibilance mitigation. My collection of headphones/IEMs are almost 98% closed back, so I know exactly how restricted they can be with soundstage - this K52 now is the most open sounding of them all, not even my planar Monolith M565c or Logitech G733 (gaming surround 7.1 headphone) can match the spaciousness. And last but not least, the comfort level has been elevated quite favorably. During the testing of this K52, I have worn her continuously for over 5 hours until I fell asleep. The pads very gentle on my ears and the clamp force was very forgiving.

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Advanced Stage Mod:
Now that my K52 has undergone a fair amount of burn in, so begin the next stage which included:
- Total replacement of stock cable to MMCX ports
- Bumped up the impedance from 32 Ohm to over 100 Ohm with Carbon Film resistors
- New DIY high quality silver plated copper cable with 3.5 & 4.4mm Balanced options
- Tinker with Bass breather hole

As seen in the pics, this K52 is actually very accessible and easy to mod. There's no complex component to worry about. First order of the day was to solder in the two inline Carbon Resistors to achieve the combined impedance of 166 Ohm. The reasons for this is simple, my primary sources which are the Cayin N6ii E02 and N3 Pro both offers powerful Phone Out juice rated at 600-800 mW @ 32 Ohm between the both of them. Also I have LG V35 ThinQ which can operate at better fidelity with higher impedance headphones. As how I have learned from experience, to make a headphone full sounding the higher power pumped the better it is, but it will need the protection of suitable impedance resistors at higher value.

In one of the pics, I have marked two Bass Breather ports - one which was already there and a new one I made by simply poking my hot solder tip which resulted in a 3mm hole. The result of this, immediately the mass of Bass were audibly stronger - in fact it was too strong for my taste and I reverted to the stock setup by covering the new hole with a foam tape. So at the very least if you prefer stronger bass you could always make new holes, could be anywhere from 1mm to 3mm but I would not recommend going over 3mm.

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So, how does it sound like now? The crux of excellent sound always start with the source quality. And I have this covered with the use of reference grade Cayin N6ii E02 which runs full time in discrete dual DAC of ES9038Q2M and onboard Class AB balanced amplifiers with four OP1662 - which provide me with fidelity level better than my Laptop rig. And I use Tidal lossless Masters and Hifi in offline mode (no streaming).

I will make this simple, the sound is outright blissful. Taking both Etymotic ER4SR and K701 as my point of reference, my K52 now stand equal to them both - literally akin to combining the ER4SR+K701=Modded K52. The sound remained sparkly neutral. The timbre oozes with clarity and resolving details, yet never artificial sounding. However my Monolith M565c remained the most analogue sounding to my ears, but it does not mean the K52 is less organic - it's just simply very tidy and disciplined. With higher output made possible with higher impedance, audibly slam and punches are present in spades - something which I find slightly lacking with K701. Playing through Russian Circles "Harper Lewis" I just can't stop my head bobbing with the tunes, percussions slams with visceral authority, bass richly layered and tight, cymbals splashing with very refined decays, guitar riffs grating with controlled energy. Switching to the more intimate side of sound, Alison Krauss "If I Didn't Know any Better" - things gets lush and velvety smooth, resolving presentation. Admittedly her vocals are not as intimate close as how it would sound through my ER4SR, but all the same I love it. So now instead of standing right in front of Alison Krauss, I am 3 steps back immersed in the lush imaging.

As it turned out, my modded K52 exhibited superb agility and flexibility as well. I threw extreme Lo-Fi early Darkthrone to the shouty Lifelover at her and she handled them all deftly. Unlike my ER4SR which is very picky of recording quality, this K52 is a lot more forgiving, which I believe due to excellent dampening of sibilant edges (this also indicated that my ER4SR extends further in the frequencies).

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Conclusion:
As I mentioned earlier, I love supporting underdogs and this K52 deserves the merit for being an obscure gem requiring some polishing. So does she sound like a $360 headphone now? hell yes she does - and perhaps even more. I have spent lots of time before this digging for hidden gems, and there's nothing that can compare to this K52 when it comes to producing plausible results. I find myself using her to enjoy music more than the rest of my cans, which means my ER4SR are now used for pure mobility, and I still very dearly love my Etys. Just that I can't wear them at the same time :)........
 
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Apr 4, 2021 at 7:06 AM Post #3 of 8

OspreyAndy

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Thanks for a great post. Not sure how far I want to go modding my K52 (also have K92) but have just ordered a pair of Misodiko pads (the size you used, they have two sizes). Been using wang yifei velours.
My pleasure. I will also be trying out a few more pads like protein leather and the thicker 30mm versions, just for the kick of it
 
Apr 15, 2021 at 8:01 AM Post #7 of 8

Muddy Walter

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Regarding velour pads, have now tried & compared the misodiko (aliexpress) with wang_yifei (ebay). The misodiko are cheaper (from China to UK * $15.54 against $24.82 for wang_yifei) but both look very similar. The misodiko are less soft both in terms of external material and foam filling. On K52 and K92 I preferred the wang_yifei because of comfort and neither had much difference in sound. On K240 the harder misodiko felt and sounded better, removed some muddiness improving overall clarity.
(* aliexpress charge VAT to UK on all values which is incorrect but sadly cannot find misodiko on ebay)
 
Apr 15, 2021 at 1:04 PM Post #8 of 8

OspreyAndy

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Regarding velour pads, have now tried & compared the misodiko (aliexpress) with wang_yifei (ebay). The misodiko are cheaper (from China to UK * $15.54 against $24.82 for wang_yifei) but both look very similar. The misodiko are less soft both in terms of external material and foam filling. On K52 and K92 I preferred the wang_yifei because of comfort and neither had much difference in sound. On K240 the harder misodiko felt and sounded better, removed some muddiness improving overall clarity.
(* aliexpress charge VAT to UK on all values which is incorrect but sadly cannot find misodiko on ebay)
Now you have just piqued my interest to try wang_yifei pads :)
 

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