Taken from some japanese blogger review. Amps in order from bottom to top, TTVJ Slim, UHA-4, Pico Slim, Headstage Arrow, Ibasso T4, RSA The Shadow.
Bro racoiaw intending to get a new amp to pair with yr own Walkman Z ah? Actually came across the Leckerton amps discussion on Head-fi ard last yr Oct also, shortly after I preordered my CK100PROs. Was looking ard tat time for my first portable amp to pair with my old smallish NW-HD5 Walkman, since it comes with its own built-in L/O.
Can't rem what was the exact reason, but I think it was the lack of reviews at that time that deterred me and I was looking at something smallish in size to pair with my HD5 (still didn't had my Walkman Z back then) and able to DIY change the output stage op-amps myself, in the end I picked the Audinst AMP-HP instead (main reasons being price was very wallet-friendly to me and I did not wanna splurge too heavily on my first portable amp).
Anyway, since u are currently alrdy using the JDS Labs C421 which I have also seen/heard before in real life, maybe I should share with u ClieOS's own take on the C421 against the UHA-4, in his own
C421 review blog entry. For his own impressions, it seemed that you may not notice much beneficial improvements in terms of SQ wise, if you were to switch from yr C421 to UHA-4, then again we all tend to hear things differently so he could be wrong as well. Just sharing for the sake of giving u for some reference, maybe can help u to save yr wallet along the way as well.
JDS Labs C421 vs. Ibasso T5 vs. Leckerton Audio UHA-4
Volume matched using a SPL meter to within 0.3dB of each other, I'll say there is no distinct advantage in SQ for T5. Overall, C421 (both AD8620 and OPA2227 version) sounds more detail and specious than T5, while T5 has the unique rich and smooth tone that usually associated with balanced amp (T5 has BTL ground, a type of active balanced ground). Technically, I'll say C421 is slightly ahead of T5, but the difference is small and quite subtle IMO…
But as far as hearing goes, I have to say UHA-4 and C421 are very close in performance. Note, I choose OPA209 in my UHA-4 instead of the default AD8610 as I want to try a new opamp. I already have several AD8620/8610 amp in my collection and OPA209 seems to be very popular and well recommended.
For now, my comparison is limited to UHA-4 vs C421 (both AD8620 and OPA2227 version) and T5. As far as presentation goes, I'll say UHA-4-209 is closer to C421-2227 than it is to C421-AD8620. It shares more of an upfront sound than it is on imaging. However, UHA-4-209 has the smoothness closer to C421-8620. Overall, it seems to be a mix of C421-2227 and C421-8620, but closer to C421-2227. The most noticeable parts for me are two: 1) UHA-4-209 has great bass impact, on par with (if not slightly better than) C421-2227 and definitely more than C421-8620. This could be just because the former two are more upfront. 2) The resolving power and imaging (and thus soundstage wise) of both C421 are ahead of UHA-4-209. Not by much, but it is noticeable. As far as T5 goes, I have to say it is trailing behind the above three closely. The deciding factor for me to say T5 is just behind the three is that it doesn't have overall transparency / openness in soundstage as the other three. For T5, everything is placed closer in. However, one thing I like about T5 that is better than the three is that it has the smoothest presentation of all. I can pair it with any IEM and it will make the IEM sound good. On the other three, they tend to want to push it over-the-top and reveal all the flaws. This kind of smoothness seems to be more common among balanced amp (T5 has BTL-ground, similar to active balanced ground). Regardless, I think T5 is still technically not as strong as UHA-4 or C421, though very close.
Taking O2 as the reference, I'll say, for now, C421-8620 is ahead, follow very closely by UHA-4 and C421-2227, then T5.
Anyway just to share my own take on the above-mentioned amps and my recent purchase decision, I have been looking on the horizon these past few mths on a relatively slim portable amp to match the size of my NW-Z1070, and finally the TTVJ Slim was shortlisted and purchased via Todd's site last wk, after my brief audition at Jaben. I have been thinking about getting either the Headstage Arrow 4G, TTVJ Slim or C421 since ard March period earlier this yr shortly after my Walkman Z purchase.
After much procrastination and deliberation, unfortunately the Arrow 4G was crossed off my list because of lack of demo sets avail locally, and with the short PMs I have exchanged with some previous Arrow owners on HF, the general consensus is with my current IEMs I own I don't really need the treble boost feature, in fact on the Arrow's gain setting 0 most of the HF owners I have talked to, seems to told me that Arrow's midrange and treble might be abit too distant/laidback when compared to amps like TTVJ Slim/C421.
Arrow 3G > 4G's gradual switch in implementation in terms of their bass boost feature was also changed in a sense, you can dig up some of the previous Arrow's discussion threads on HF to understand what I mean, but
PANGES's review of his own Headstage Arrow 4G vs UHA-6S comparison alrdy elaborated abit about the above issues, so I don't have to explain further.
Finally, after looking at both the C421 and TTVJ Slim designs myself upclose in person, since I can be considered a narcissist irl, I thought since the JDS Labs amp packed a more industrial look in terms of overall design, I chose to go for Todd's amp instead in the end. (of cos after demo-ing them, the TTVJ Slim's warmth and richness in terms of tonality and mids also appealed to me, as I thought that it was a great match with my CK100PRO's or any sort of neutral/analytical headphones as well)
