[risenfallen]

Quote:

Looks like a dual mono cmoy type amp.  Claims much better battery life but really not impressive, especially since you get absolutely no type of performance numbers form the seller.

 
It is based on the Cmoy design indeed. But then it drives my K701 beautifully

 

[Sherlockaled]

Dear phantompersona,
 
I just talked to fred_fred_2004 (Howard) last night about his 3 channel dual LM4562 cmoy (http://www.ebay.com/itm/3-channel-Headphone-amplifier-Audiophile-Cmoy-dual-LM4562-high-current-LM6171-/200712295581?pt=AU_Electronics_Audio_Amplifiers&hash=item2ebb62949d) . He sent me a reply that he has the same model, but rechargeable, he also sent me pictures and it looks somewhat like an update from the Cmoy dual chip rechargeable from your first post. The edges are more rounded, and it looks very nice. You should contact Howard and ask about the new cmoy rechargeable, he told me its about the same price as the one listed right now. 
 
I am still debating whether or not to wait for that product (which looks way better than a tin cmoy in my opinion), the only thing stops me from making a decision is that I want to have a long battery life span per charge, the tin cmoy allows me to change battery very easy, however the rechargeable one does not. I don't know if the 9v 500mah battery will last more than 15hours?

 

[shadow419]

Quote:

 
It's a bit on the bulky side though but build quality is hard to match. As for performance, I prefer it by a large margin to the transportable O2.

 
Quote:

 
It is based on the Cmoy design indeed. But then it drives my K701 beautifully

 
Wasn't implying that the design was bad, just that I don't really see where the large performance gap is coming from. Are you referring to the battery life, power, form factor, or something else?  

 

[risenfallen]

So far I've only tried a handful of amps (mostly budget portables) so my experience is very limited. Compared to all those amps (including the O2 and the Audio-GD Compass desktop amp), the Neco has the cleanest presentation with loads of details which becomes more apparent to me when I pair it with the K701 (even prefer it with K701 to the desktop Compass). In terms of power, it's the best portable I've heard. One thing I've noticed with the K701 (or any other full-size cans) is that their soundstage often collapses (sometimes to an irritating level) when not driven properly (or underpowered?). This is somewhat contrary to the airy, open soundstage I have when pairing the K701 with the Neco (and bass comes alive too

).
 

 

[shadow419]

Cool thanks.  I only own a few amps myself, and all of them are diy besides a jds cmoy.  So far my diy O2 has been my favorite, but once I get of my behind and finish my "The Wire" build it may change. Didn't mean to come off as confrontational, but when someone says I like A more than B, I like to know why.  Granted I don't own any really power hungry headphones, the O2 so far has powered everything I've thrown at it very well without any noise or distortion.  I have tried a friends Q701 with my O2 and it seemed to power these cans with ease.

 

[damianmb]

Quote:

I don't think I had said the dual opamp cmoy is much better. It is the three opamp (dualLM4562 + one LM6141) cmoy by the same eBayer (fred_fred_2004) that I am referring to.
However, for $150 and really more of a semi-portable headphone amp, I do think O2 is the best as long as you can live with its size.

Hi ClieOs,
 
And what about E11 vs C421? O2 is a bit chunkier for me. I like something USB powered for the sake of simplicity.
 
Thanks!

 

[ClieOS]

E11 isn't exactly USB powered, just USB rechargeable. You can't use E11 when it is charging.

Regardless, C421 is still a far better amp than E11. Performance wise, I'll say C421-AD8620 is pretty close to that of O2.

 

[Sherlockaled]

Imma vote for C421, getting one myself pretty soon!

 

[Cwgoh2800]

For desktop, I have the the Superlux HA3D. Rather great for the price. Punchy bass, nice highs. Mids are ever so slightly laid back though.
But the Headfonia review is too flattering IMHO. http://www.headfonia.com/superlux-ha3d-amplifier/

 

[JuanseAmador]

Portable
 
JDS Labs CMoyBB ($70)
PA2V2 ($70)
Fiio E10 ($88)
Graham Slee Voyager (can't remember)
Fiio E17 ($140) ($200 Amazon)
HeadStage Arrow ($300)
 
Semi-Portable
 
C421
Objective 2

 

[Sherlockaled]

Quote:

Portable
 
JDS Labs CMoyBB ($70)
PA2V2 ($70)
Fiio E10 ($88)
Graham Slee Voyager (can't remember)
Fiio E17 ($140) ($200 Amazon)
HeadStage Arrow ($300)
 
Semi-Portable
 
C421
Objective 2

I don't know how the E10 can be classified as a portable amp??? It does not run without power via USB cable

 

[damianmb]

Quote:

E11 isn't exactly USB powered, just USB rechargeable. You can't use E11 when it is charging.
Regardless, C421 is still a far better amp than E11. Performance wise, I'll say C421-AD8620 is pretty close to that of O2.

 
I see Headfonia recommending HIGHLY recommending OPA2227 over that one, I also noted they disliked the O2. I know there is a lot of controversy around the O2 kind of sound and also the AD8620 which I guess is the same kind too.
 
What is the difference between both? Will they perform better of worse depending on the Headphone used? I do like vocals/mids, instrument separation/detail and tight bass.
 
And in another aspect, will the C421 drive correctly an HE-500 (if I ever get a big $$$ bonus ) or it will fall too short?
 
Sorry for so many questions, trying to decide my next component and either go inexpensive (CMoy) or get something that will last.
 
My equipment: Dacport LX (still to be shipped), HD598, Panasonic HTX7, SE215 and Yamaha EPH-100.
 
Thanks!

 

[ClieOS]

I see Headfonia recommending HIGHLY recommending OPA2227 over that one, I also noted they disliked the O2. I know there is a lot of controversy around the O2 kind of sound and also the AD8620 which I guess is the same kind too.

What is the difference between both? Will they perform better of worse depending on the Headphone used? I do like vocals, instrument separation/detail and tight bass.

And in another aspect, will the C421 drive correctly an HE-500 (if I ever get a big $$$ bonus ) or it will fall too short?

Sorry for so many questions, trying to decide my next component and either go inexpensive (CMoy) or get something that will last.

My equipment: Dacport LX (still to be shipped), HD598, Panasonic HTX7, SE215 and Yamaha EPH-100.

Thanks!

You should also note that I HIGHLY disagree with that review, given that I also hear all three of them (O2, C421-2227 and C421-8620). In a way, I personally find that review very misleading to many that have never had the chance to listen to all of three but need to base their buying solely on such opinion.

Here are some of what I have posted in the C421 thread:

I have received a loan unit of OPA2227 based C421 this morning to compare to my AD8620 version as well. I haven't put enough time on the new comer but suffice to say, I can already tell the subtle difference between the two C421. It is almost like the last time I compared the stock cmoyBB (which is OPA2227 based) to the AD8620 rolled cmoyBB, except this times both C421 sound much better than both the cmoyBB in every way. Like last times, the AD8620 wins over OPA2227 for me again. Not something night and day, but enough to call out a winner.

However, this is not to say AD8620 crashes OPA2227 in every way. I love the AD8620, but I can understand why someone would find it V-shaped sounding and prefer the OPA2227 instead. It has more to do with the slight difference in presentation between the two opamps (and I had observed the same in cmoyBB as well) - AD8620 has really great soundstage and portrays the image in a very 3D fashion. In a way, it is almost better in imaging (especially in depth) than the O2 and that's quite an amazing feat on its own. OPA2227 on the other hand puts everything upfront with a sense of rich and warmness between the tones. If we were to take O2 as our reference for what 'totally neutral' / standard should be, then AD8620 would be the equivalence of what 3D TV meant to normal TV (where you get the surreal 3D effect) while OPA2227 would be equivalence of sitting close to a HD TV vs. at normal distance (where you get to see the fine detail in individual element but not quite so over the whole picture).

As mainly an IEM user where soundstage is generally more limited, the extra layer of depth that AD8620 brings to the table is a real killer feature to me. It just goes really well with all kind of IEM (*the synergy with Etymotic ER4S is unbelievably good for an IEM that is always considered to be flat sounding). But that same extra layer of depth might not be that appreciated for full sized headphone user (where soundstage is already good) or simply for those who rather prefer an upfront presentation. Instead, I would think they will find AD8620 adds a sense of hollowness to the presentation which might not be to their liking. That's probably why AD8620 is interpreted as V-shaping by some, even though the FR curve is perfectly flat for both opamps.

So what is my early conclusion? I'll still recommend C421 with AD8620 over OPA2227 for its more rounded presentation. But for those who rather like a little bit more richness over imaging, the OPA2227 based C421 could work out better for them. Both are really great sounding amps, and I think the choice is every bit personal preference as it is performance.

Will write a more completed review once I have enough time with them, and will include a comparison to JDS's own O2 as well as cmoyBB (plus a few others).

Yes, I'll say your assumption is closely mimic my experience with both version of C421. AD8620 version is indeed closer sounding to O2 than OPA2227 version. If you are using IEM mostly (which I am), I would think AD8620 is most likely the better pairing of the two. OPA2227 version would be a better pairing for full size headphone IMO.

Yes, C421-AD8620 is very similar to O2 in sound, but not so much with C421-OPA2227.

I think the most important point why I recommend AD8620 over OPA2227 is the fact that AD8620 gives much better imaging and soundstage to IEM (which is something IEM always seems lacking when compared to full size). OPA2227 on the other like to put thing upfront - it might seems wider on the side, but the true is you are not getting as much depth as you can. With IEM, where depth is generally a weak spot, the AD8620 offers something OPA2227 doesn't have. As for brightness - I won't say AD8620 is very obviously bright compared to OPA2227. AD8620 just handle the detail more delicately, and makes the listener listen to the detail more plainly. But the true is I can hear just as much detail in OPA2227 as well, but they are generally hidden behind ./ obscured by the richness of the tone and you'll have to pay more attention to find them out.

When compared to AD8620, OPA2227 gives slightly better width but it totally loses in depth, layering and transparency. Unless you only like your soundstage from side to side but not from near to far, I'll say AD8620 is hands down much better in soundstage.

I also personally think that trying to driver hard-to-drive headphone with portable amp is mostly a waste of effort. Sure, in some case you can expect really good SQ when driving hard-to-drive headphone with portable amp. C421 probably will do a very admirable job as well. However, it will not likely going to beat a desktop amp simply because of the limitation of power and PCB space for the circuit. If you have spent that much money on a full size headphone, I don't see the point of not trying to get the best out of it. Personally, I'll invest in a good desktop amp and treat portable amp as more of a compromise for traveling.

 

[Mozu]

Which I always find funny, as I heard the C421-AD8620 pretty much exactly how Headfonia did (and about two months before they ever got their hands on one). Subjective hobby is subjective.

 

[ClieOS]

Another interesting point is John@JDS and the testers he had during the R&D phase seems to share most of my opinion as well, which of course is the reason why he has offered AD8620 as the default opamp at the first place. However, as you has said, perhaps it is all subjective.