I am the one with PS-HX500 running it with brand new Nagaoka MP-200 since yesterday. Posting here my comments on upgrading the OEM head, and since I am not a Pro but rather a Vinyl fan... don't criticize me too much if I did smth wrong
My choice of HX-500 was motivated by its ability to rip up to DSD 5.6, and for someone with Astell&Kern 120 II in the pocket and growing collection of LPs that sounded as good solution. Several positive reviews in the media, including couple where authors were telling about its upgrade flexibility were found as well. Bad for Sony, they did not provide any relevant information on tonearm, shell and needle. Anyhow, I gave it a try.
First, even though the installed head was conical with 3 gramms of pressure, my first impression on its sound was quite positive. I was running AT 440MLb with AT-120 DD before, and it sounded good, but... in reality its highs were too high whatever I tried to adjust. Some people said that Sony installed a custom-made AT-91 needle, my impression it more looks like and based on specs as Denon DSN-82, ie. 2.5-3 gramms pressure, 3 mV output, 5 gramms total, no other information was found since it's out ofmstock already.
My next day I tried AT- 440MLb. One review was recommending AT-120 as a possible upgrade, but 440 is what I had. Luckily, the heigth of OEM head was 17 mm, same for 440. The only pain was to dis-connect cables and re-connect them again, since Sony has no shell. Well, the sound improved a lot, which was kinda expected... but same thing - it was to high and too synthetic on the high end. However, if you like 440 sound, you can upgrade it, and it will improve the sound, and play in a typical sound picture of AT-440. To be honest, I didn't play to much with phono-corrector, may be slight adjustments could be achieved. But that was classic mid-range AT needle sound reproduction. Period.
MP-200 is my first Nagaoka, and my choice was mainly driven by vinyl community comments and reviews, as well as many samples heard, comparing it with AT and others. Two breaking points for me were: better (deeper and tigther) lows and smarter highs (authentic, intelligent, delicate, embracing and natural). Well, this is what I've got finally. Happy!
Things to consider:
1. MPs are 18.6 mm high vs 17 mm original. Sony's rubber mat is 5 mm thick. You can balance this deviation with 3 mm matt and get those almost 2 mils "back". Tonar has quite good rubber matt of 3 mm. This is important, I believe, to leep the same distance between the disk and the needle body.
2. Since Sony is silent on tech specs on tonearm, you gonna play a while with finding the right point for the needle. Mine picks disk surface now almost exactly where the needle point dot marked on the tonearm. Anyhow, final adjustments will be taken after 50 hrs run, but so far I don't hear anything that worries or buzzes me.
3. Not tried yet, but will play with pF swithches later. So far the sound is well balanced, I even like a delicate drop in mid-range. Hi-range may sound as "not enough" (after AT), but it pleases me more now.
Again, I am not an expert. And English is not my native language.
In Vinyl We Trust