[Kanashimu]

I plan to use an amp with my Miracle. It'll probably be paired with the DX100 if I can get one. I've heard of lots of good things about the Objective 2 / DX100 pairing, but how does the c421 compare?

Its strictly for home use - I won't carry and amp + a brick for portable use, so disregard the portability or battery life of the amps.

Thanks.

 

[F900EX]

I have asked the same question myself. If anyone in the USA is going to buy and O2 and interesting doing a loan swap just to hear the difference, I'd be interested.

 

[syphen606]

Have a C421 at home now.. and will get the last of the parts needed to finish my O2 this week.  I'll let you know my opinion between them soon.

 

[Kanashimu]

Interesting, thanks.

 

[ahntorage]

Was there an update on the difference you experienced between the two?

 

[i_djoel2000]

i've tried both. o2 is just the better amp, no competition there
 
o2 sounds much smoother, balanced, and more bodied

 

[deviusdragger]

I like my O2 amp!!!!

 

[KGee]

Headfonia also said that the O2 beats the c421 in terms of sound.  If you have no need for portability, I think buying or building an O2 would be the right choice.

 

[jseaber]

The difference isn't too pronounced. If you only need a home amp, then by all means go for the O2. The price is lower and it will out-benchmark anything in its class. But that's where Voldemort cheated: designing in batteries doesn't make a device portable. Portability is about size. O2 is not small!
 
c421 sacrifices very little in terms of SQ to gain a great deal in features and portability. It's hard to go back to the O2 after listening to c421 with bass boost.

 

[F900EX]

See, this is were I am more undecided after reading the above .... I could buy the 2 amps, I just don't need 2 amps. I feel the one that I do like, I will use all the time. The other one will sit in a draw forever. I look at it as a waste.
 
 
Seems like sound wise the O2 beats the c421. Were the O2 does not beat it, is in the bass and portability dept. 
 
I'm going to assume the c421 will beat the O2 in terms of sound stage and clarity/details.  O2 sounds like a more natural sounding Amp.
 
 
 

 

[deviusdragger]

f900 i say just buy 2 used ones, keep the one you like. Im sure youll have no problem selling either of them on here. Unless your like me and just keeps both of them, just to say you have them both :-/

 

[syphen606]

In listening to my 8620 C421 and O2 with my HD650's back to back, they are very similar sounding to MY ears. I will admit that the O2 is ever so slightly better but like has already been said loses out for me once the bass boost gets turned on!   A few of my headphones sound much better with bass boost like mt 558's or my RE-262's.

 

[Mozu]

Weird. The AD8620 C421 sounded so v-shaped to my ears.

 

[ClieOS]

Weird. The AD8620 C421 sounded so v-shaped to my ears.

If you are comparing AD8620 to something like OPA2227, then I would understand why you will find AD8620 to be V-shaped - well, perhaps V-shaped isn't the word I would use. OIPA2227 is a fairly flat and forwarded sounding opamp to my ears. AD8620 has much better depth and image in comparison. I would think those who rather prefer an upfront presentation might find the more specious AD8620 unappealing. I am more of fan for the AD8620 myself.

 

[jseaber]

 
Quote:

If you are comparing AD8620 to something like OPA2227, then I would understand why you will find AD8620 to be V-shaped - well, perhaps V-shaped isn't the word I would use. OIPA2227 is a fairly flat and forwarded sounding opamp to my ears. AD8620 has much better depth and image in comparison. I would think those who rather prefer an upfront presentation might find the more specious AD8620 unappealing. I am more of fan for the AD8620 myself.

 
It's difficult to understand interpretations like this, considering audible range frequency response is flat for c421 and the O2. Mozu must be describing something else, as you suggest.
 
This would be easier to settle if we could place the O2's output opamp in a c421. Alas, NJM4556 isn't available in the SOIC-8 package.