Disclaimer: Mezzo HiFi modded my AK100 free of charge. The mod goes for 500$ USD. You can find all about it here: MS-AK100 mezzo soprano.
I don’t swear a lot. But when I do, I swear hard. Like when I swore the following in my review of the MS-AK100:
Mezzo Hifi’s MS-AK upgrades do away with some of the worst interface design this side of auto-squirting bidet, and produce sound quality that no portable amp, and no portable DAC at any price can come close to approaching.
Looking back, I may have said too much about a product that I didn’t fully vet. The press sample I borrowed did perform exactly as noted. It was phenomenal through most tests, at all volume levels. The MS-AK100 transformed the kludgy AK100 into a truly high-performance device.
Most exclusive audiophile DAPs out there are anchors - sharp, finger-goring boat anchors. They take 3 hours to charge up, and 4 to charge down. They weigh down belt-less trousers, severely lighten wallets, and clutter the desks of designers whose job it is to document every useless feature in their spec list. Audiophile players follow Moore’s Law almost to a tee: doubling both price, and bloodletting corners every 18 months.
Which is why mods to the compact - and comfortable - AK100 are important. The Red Wine RWAK100 — reviewed here — is great. But it does nothing to roll back the AK100’s ever-present hiss. MS-AK100 mods do the following (kindly explained in everyday English by Lin Zhi Yong in a reply to this ohm image Facebook post):
1. Replacement of WM8740 to WM8741.
2. Hooking up a micro-controller to the WM8741 so that it can run in software mode.
3. Replacement of the volume encoder so that it works with the micro-controller. This allows you to use the MSAK100/120 as a standalone player.
4. Adding a switch for you to switch between soft-knee (slow roll-off) and apodising (fast roll-off) filters in the WM8741.
5. Resistor bypass to lower the output impedance to 0.1 Ohm
6. Replacing the optical input jack with a line-level 3.5mm TRRS balanced output.
I had Mezzo HiFi modify my own unit. I would continue the review with long-term commentary. Unfortunately, my unit came back, all Christmas-treed up, but with none of the performance benefits that wowed me in the review unit. In fact, with the exception of less hiss, my unit performed as bad under load as the original AK100.
Worse, until after purchasing the Lynx HILO (reviewed here), I didn't bother following up my review. At the time, I was stuck with the Edirol FA-66 which had served me faithfully since Touch My Apps. It sufficed to show load effect, including decreases in SNR and dynamic range. But it wasn’t up to more than general measuring snuff. I refused to publish its RMAA results for the simple reason that any good source was completely limited by it. I couldn’t reliably document files that surpassed 16-bit spec. But even the FA-66 proved that the unit Mezzo HiFi modded for me suffered intensely under load. Still, I didn't publish my concerns.
It gets worse. In August, I measured my dud MS-AK100. Then I sat on the findings. Deplorable. I beg no one’s forgiveness. I only offer my apologies. I got busy. I went to Canada to commune with the deer flies and mosquitos and tell my crying parents that I was an atheist. Publishing measurements of the MS-AK100 was low on my to-do list. But I should have. The unit they modded for me sucked.
And until yesterday, I didn’t mention it. I should have. Especially since I was (and still am) one of the MS-AK100's most vocal champions. If you purchased a unit based on my review and your unit doesn’t perform up to the praises I sung, please complain to Mezzo HiFi. They owe it to you to re-mod your unit.
The great news is that after its second trip to Thailand, my MS-AK100 performed up to the expectations established by the press review unit. But that doesn’t excuse the fact that the original unit they modded for me did not. A 500$ USD mod to improve sound should first and foremost improve sound. Ensuring that paying customers receive properly working units should be top priority for any company worth its salt.
Now, if your MS-AK100 works as advertised, for a majority of sensitive headphones and earphones, it will perform as good, or better, than basically an DAP out there. In some metrics, it is the best-performing DAP I've tested, bar none. To illustrate the differences between a properly modded MS-AK100 and an improperly modded one (not to mention a couple of extras), I have cued up the below benchmarks results from the following DAPs:
1. an improperly modded MS-AK100 (old) - RMAA results
2. a properly modded MS-AK100 (new) - RMAA results
3. an AK Jr - RMAA results - Headfonia review
4. an AK380 - RMAA results - Headfonia review
The following Rightmark Audio Analyzer tests were conducted through this equipment.
Source: Mezzo HiFi MS-AK100 (500$ USD)
ADC: Lynx Studio HILO LT-TB
Computer: 2012 27" iMac
Cables: 1,5m Hosa Pro 3,5mm stereo to dual 3-pin XLR (around 8$).
NL - no load
SM2 - Earsonics SM2
ES7 - Audio Technica ES7
DT880 - Beyerdynamic DT880/600
Table 1 RMAA 24bit / 44kHz - no load
Table 2 RMAA 24bit / 44kHz - Earsonics SM2
Table 3 RMAA 24bit / 44kHz - Audio Technica ES7
Table 4 RMAA 24bit / 44kHz - Beyerdynamic DT880 (600Ω)
While the MS-AK100 gets all flustered at high-volume levels when driving the Audio Technica ES7, so do all players. And, it's fair to say that no one would listen to testing levels without severe pain. and hearing loss. Apart from harmonic distortion, the baseline performance of a properly-modded MS-AK100 generally pushes beyond a loaded AK380.
I stand behind my original review. The MS-AK100 is one of the best, if not the best-performing DAPs out there. But it comes with a proviso: that Mezzo HiFi's current quality control may not be up to snuff. I am not the only one with questions regarding a modded player. But I am hopeful that the QC issues noted in this article will be addressed.
Why? Because properly done, Mezzo HiFi's mods are incredible. They are worth every penny of the 500$ they cost.
Full RMAA reports below: