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.
Prior to releasing an official apology, it is meet to be up front about the performance of my AK100 which Mezzo Hifi modded. Next to the one I reviewed at Headfonia, and the one I previewed here at ohm, it is piss-poor. At my request Mezzo agreed to look again at the same unit. If it was out of spec, they would fix it. The results speak for themselves.
Whereas a properly modded MS-AK100 stands in the same ball park as a 3500$ USD AK380 (measured here), an improperly modded MS-AK100 performs no better than a pre-modded AK100.
The short: there are at least two Mezzo Hifi MS-AK100 mods out there: ones that performs really well, and ones that don't hiss. The latter are crap. Following my review of the MS-AK100, I would understand if you purchased one based on my recommendations. The press sample was brilliant. It is possible that because it was so good, it was sent out for review. I hope that isn't the case.
The following are the results of the unit Mezzo HiFi originally modified for me. As you can see, these mods are anything but inspirational. And, they go for an extra 500$ beyond what you paid for your AK100.
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$).
NL - no load
SM2 - Earsonics SM2
ES7 - Audio Technica ES7
DT880 - Beyerdynamic DT880/600
24-bit TARGETS and loads
24-bit TARGET - no load
The MS-AK100 modified for me by Mezzo Hifi holds a very good signal to unloaded sources. But it utterly fails when loaded. In comparison to the new mod which Mezzo HiFi performed for me in September, the results are night and day. Today's 499$ USD AK Jr performs far BETTER (RMAA results AK Jr) player than an improperly modded MS-AK100. A properly modded MS-AK100 is in another league.
If, after reading my review you purchased an MS-AK100, I must apologise. It is possible that your unit performs up to spec. But if it does not, it was not worth the time, money, and effort you paid to have it modded. Please accept my apologies. And, please have yours checked. It's easy to check for load errors. All you need is a simple sound card and a y-splitter. If the volume of your MS-AK100 drops off (in a voltage tester or external software) visibly, you have a dud. If RMAA tests reveal massive drop offs and cut outs as seen above, you have a dud.
Dud MS-AK100s are a complete waste of time. Units whose voltage doesn't drop off are proper mods and are worth every penny.