[wje]

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I just ordered mine as well last night (AD8620 also).  I went with the default USPS shipping, so I'll probably get it towards the end of the week, but I've still got my new-ish (maybe a month old now) Ibasso D7 DAC/Amp to play with in the meantime...
 

I believe the default shipping is USPS Priority Mail.  You should see it as early as Wednesday.  Priority Mail has been good for me lately - seems awfully quick, and the price isn't too bad.
 

 

[syphen606]

Spent all day listening to Shure SE215's on the C421 (8620). Really do love this amp..

 

[Cassadian]

If only I could get my hands on those, I have no idea where'd I'd fine some for a cheap price.
 
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I actually don't really have any issues with the c421 and the Westone 4's. My issue was actually with the Ultimate Ears UE4, which are (were) my main IEM's. I'm currently using a pair of Ultimate Ears UE11 Pro, and they're just as sensitive, so the issue is the same with these. On a side note, if I do turn the volume up to make the imbalance go away, it does sound really nice with the UE11. Just a bit loud for my comfort. In any case, I'm in the market for a portable DAC/Amp combo, so I don't mind letting go of the c421. 
 
I'll have the amp shipped out for you tomorrow!
 
Side note: If you get a chance, try the c421 with the Etymotic ER4S. The c421 just really did something special for me with those IEMs. 
 
 

 

 

[guhmo]

I'm thinking about getting a C421 for use with my UM3X.  They're 125 db/MW and have 56 ohms of impedance.... synergy's hard to find with these IEMs... Would the C421 work well with it?

 

[ClieOS]

 
Good Stuff

 

[Mutnat]

Quote:

 
Good Stuff

Indeed!  You can definitely see the family resemblance.  My c421 should be here any day now (shipping to Canada can take forEVER sometimes).

 

[808Ronin]

Received c421 today (one day earlier than expected) and all i can say is WOW. Sounds great straight out the box using westone 3. Big improvment over cmoyBB and worth every penny. Im looking forward to hearing the improvement in sound once properly burned in, as reported by other forum users.

 

[PANGES]

Oh wow. I never looked at the dimensions, but I didn't think the O2 was that much bigger than the C421. lol.
 
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Good Stuff

 

 

[ClieOS]

Quote:

Oh wow. I never looked at the dimensions, but I didn't think the O2 was that much bigger than the C421. lol.
 

The only thing that makes O2 a portable amp is that it is powered by batteries. It is really more of a transportable in practical use.
 

 

[wje]

Wow.  Seeing both amps in the same picture really puts the size issue into persepctive.

 

[Ultrainferno]

I'm listening to the C421 now, with the OPA2227. I like it a lot, only arrived last night, so can't say much yet.
The O2 also arrived but I need to find a new AC/AC adapter first...

 

[Donnyhifi]

The AD8620 version of the C421 has arrived and it sounds wonderful after about 40+ hours of burn in. I feel that it sound quite neutral, transparent with nice clear treble, good bass extension and a wider soundstage. There is a good amount of power and the noise floor is great as well. You can only hear hiss if you crank it up but at these volumes you will have other problems to worry about such as permanent hearing damage. I can't hear any hiss on my sensitive Fitear MH334 customs or with the UM3X at normal to quite loud listening levels. This is a quality piece of equipment and I'm quite satisfied with the sound and build quality of this product.

 

[wje]

Just a quick thought ... is anyone (US Based) interested in trading their C421 for a genuine JDS Labs O2 amp that is only a few weeks old?  Of course, a small amount of cash (PayPal) would be supplied to off-set the price difference between the O2 and the C421.  The O2 features everything that JDS Labs offers when they ship - Black allied aluminum case, silver front panel, nice aluminum knob with 2 rubber rings so it can easily be turned, (2) 9V rechargeable batteries, Triad power supply.
 
If you might be interested, let me know.  I have (2) O2 amps and was interested in trying the C421, too.
 
Thanks,

 

[bluishgreen]

 
After almost 50 hours of burn-in, I started listening to the C421 w/AD8620, which sounds really good.  One thing that that really strikes me is how similar it sounds to my Ibasso D7--maybe a little wider soundstage with the C421 on some recordings (not deeper, but wider) but extremely similar in tonality and SQ.  The funny thing is, previously I was looking at this as an alternative to the built-in amp on the D7, which I thought was a tad too warm for me after 100+ hours of use.  But since then, it seems like the D7 has actually become less warm even after the 100 hours (it has a lot of caps).  When I first got the D7, it seemed just as warm as my Fiio E10, but now it seems a bit brighter than the E10.
 
I'm now liking the D7/DT880 combo more and more, prior to even hearing the C421.  Now that I have it, I plug the C421 into the line-out of the D7 and switch back-and-forth between the D7 DAC/D7 Built-in amp combo vs. the D7 DAC/C421 amp combo, and am surprised by how similar they sound in tonality and SQ--at least with only around 50 hours of burn-in on the C421.  According to posts in other threads, Ibasso support said that the D7 uses the OPA1611.  I don't have any great cable connecting the devices, though, and am just using a stock cable that came with another amp, so that could limit things.
 
Doing the same A/B testing (using the same cable) with the Fiio E10, I definitely notice an uptick in SQ with the C421 as amp vs. the E10's built-in amp--but it's harder to detect a difference with the D7.  Although I do also like the combo of the E10 as DAC-only with the C421 as amp.  I've only used the C421 on its own (no DAC) for a little bit, but it sounds great by itself using an LOD into an iPhone 4S as well as a basic 3.5mm cable into an Amazon Kindle, listening to some "-q9" Vorbis files.  Very clear and defined on both devices without any over-the-top brightness or obvious sibilance.
 
In terms of phones--since they sound very similar to me, I'm liking the C421/DT880 combo every bit as much as the D7/DT880 combo.  The AD8620 suits the slightly-warm DT880's extremely well.  What I didn't expect is that the AD8620 works fairly well with the K702's--although admittedly, I haven't tested them nearly as much as the DT880's, only listening to one album with the K702's.  Keep in mind that I only use my K702's when listening to 100% acoustic instruments, so I can't vouch for anything else.  In any case, I had expected the combo to be too harsh, but haven't found the K702's to be harsh so far.  Maybe because of all the prior talk of "brightness", it skewed my expectations…but I don't find the AD8620 to be extremely bright--I find it to be pretty neutral and defined.
 
Also, there's more than enough power to drive the K702's, DT880's, and DT990's, although I've only tried the DT990's with one song, so I can only speak on power for those right now, not SQ.  In any case, like others here, I'll continue playing around with things…
 

 

[Cassadian]

Would it make sense that to me the amplifier would make no difference considering I the C421 is my first amplifier?  + I just realized how softly I listen to my music as I often am teetering on the edge of imbalance with my low impedance headphones.