[gelocks]

A few more impressions here:

https://www.facebook.com/headfonia/posts/211639922252107

 

[kyoshiro]

the c421 is pushing my hd600 fine without high gain... amazing!

 

[TheOneInYellow]

I have finally, finally, wrote my impressions of my Custom cMoyBB v2.02 amp, John Seaber, and my future plans, in this post on this topic.
 
So, why am I posting this bit of information here? I am going to, very soon (this week) purchase the C421, and I will be in contact with John. I will post anything of relevance from our conversation (that is not personal), and will make note on my initial impressions of the new amp when it arrives.
 
 
This is a significant investment for me (as is the recently bought at a discount Ultimate Ears Triple.Fi 10 Pro IEM's from Amazon.co.uk), and along with some other possible purchases (a new LOD from Moon-Audio.com, custom sleeves/tips, and a replacement UE cable from Fiio, all written in my post linked above), will become a major feature of my audio rigs, home and portable, for some years.
 
To those who own the C421 amp, could you post some impressions against other amps just for interest? Thank you

 

[kyoshiro]

Get the AD8620 if you're not driving high impedance phones. My AD8066 version is good but its probably too much on power side and not enough in clarity in my opinion. Gotta love lithium batteries though. Maybe i'll buy the AD8620 version when the new cases are ready for my Ie8s cuz man the aesthetics of this amp is superb.
 
Quote:

I have finally, finally, wrote my impressions of my Custom cMoyBB v2.02 amp, John Seaber, and my future plans, in this post on this topic.
 
So, why am I posting this bit of information here? I am going to, very soon (this week) purchase the C421, and I will be in contact with John. I will post anything of relevance from our conversation (that is not personal), and will make note on my initial impressions of the new amp when it arrives.
 
 
This is a significant investment for me (as is the recently bought at a discount Ultimate Ears Triple.Fi 10 Pro IEM's from Amazon.co.uk), and along with some other possible purchases (a new LOD from Moon-Audio.com, custom sleeves/tips, and a replacement UE cable from Fiio, all written in my post linked above), will become a major feature of my audio rigs, home and portable, for some years.
 
To those who own the C421 amp, could you post some impressions against other amps just for interest? Thank you

 

 

[TheOneInYellow]

Quote:

Get the AD8620 if you're not driving high impedance phones. My AD8066 version is good but its probably too much on power side and not enough in clarity in my opinion. Gotta love lithium batteries though. Maybe i'll buy the AD8620 version when the new cases are ready for my Ie8s cuz man the aesthetics of this amp is superb.

 
Thank you for your reply, and you have confirmed what I had always thought.
 
I am indeed going for the AD8620 if I buy the amp (might be today

), simply because the only high impedance headphones I own is the AKG K 701, which for anyone who knows, is not that high at all. Indeed, it's rating of 62 Ω is fairly efficient, though it is difficult to drive.
Since I use my AKG K 701's so much, I prefer transparency and openness to my music, but I do like good bass. The K 701's are pretty good at this, though with my current amplifier, the NuForce Icon, it is not as detailed as my Etymotic Research ER-6i's using my JDSLabs Custom cMoyBB v2.02.
The major selling point is the battery, portability, slimness, recharge functions, gain settings, and the Bass Boost switch. Oh, and the minimalist aesthetics; even if the Batch 2 faceplate's aren't as good as John and co like, they are still awesome looking (from the pictures I have seen), and the possibilty of getting the Batch 3 faceplate's in Feb for free (excluding the shipping cost) makes it a very good investment.
 
So, for that reason alone, the AD8620 is essential to make my AKG K 701's really sing.

That transparency and power from the opamp will eclipse my NuForce Icon.
More so, the bass boost feature that I use in my Custom cMoyBB v2.02 (exclusively for the ER-6i's) is also present on the C421, and looking at the spec sheet, its better than my cMoyBB; this means I can use it on my K 701 on some recordings, such as Trip-Hop and Electronica (some rock, but depends on recording), and turn it off for almost everything else, especially classical. In fact, I hate using the BB feature when using my K 701's with NIN records, as it does not work well, but I guess that's more to do with the cMoy amp; I shall test if the C421 will fair better, but I bet that Trent Reznor's music, especially his Ghost I-IV and recent soundtracks (with Atticus Ross) will sound better without the BB switched on. If I were to listen to, say, Daft Punk, then the BB will be switched on, because "Daft Punk is playing in my house, my house".

The BB will also be used for the K 701's when I play films from my PC using Dolby Digital (Asus Xonar D2X and CCCP with Media Player Classic- Home Cinema), and/or when I play Xbox 360 games (non-multiplayer or co-op) using my, poor, but cheap and decent, TurtleBeach EarForce DSS 7.1 Dolby Digital sound interface (if I play MM or co-op, I use a stereo set-up and my JohnBlue AudioArt JB3 speakers).
 
BB will probably not be on most of the time with my UE Triple.Fi 10 Pro's (I doubt it needs the boost) except if I use it for films and Xbox 360 games (as described above), though I will test if this is necessary. Otherwise, the AD8620/Triple.Fi 10 pairing will be pretty awesome.

 
As for the ER-6i, I cannot imagine not using the BB at all, and I love how it retrieves detail from music, but it is very fatiguing. The AD8620 and BB will really help me use the ER-6i's for longer, as is the case with my Burr-Brown OPA2227P Custom cMoyBB v2.02 with BB on.

 
Yeah, I don't need the other op-amps in the C421, as I can have the best of both worlds; transparency, and bass boost. WIN!

 
I like the idea of owning another C421 with a different op-amp (such as your AD8066), but instead, I might put that money towards owning the Objective2 from JDSLabs.com as part as my desktop headphone amplifier instead. That is for later (maybe sometime this year), but for now, the C421 has my heart.

 
Do you think my usage plans will work for my headphones and media?

 

[kyoshiro]

The batch 2 face plates are nice but the cutting is like 1mm off at some places lol 
But yeah the bass boost is a good feature, however dont need bass boost when its IE8 @ max bass + AD8066 = too much lol.
The intention at first was to actually have the C421 to push my HD600s thus AD8066 cuz of the 300ohms but 300ohms is like a peace of cake... even 600ohms thus the AD8620 op amp is sufficient for 300ohm. 
Oh and with the Objective2... I have a PCB board coming and I just placed an order with Mouser for parts =p just gotta sort out the casing. As for desktop amp, i have 2 stationary amps atm, and will be buying a Schitt Lyr + Bifrost when the current stock arrives to HK so im sort there! 
Dont forget the interconnect cable is also quite important =p I've found a good combination with my rectangular solid core ipod LOD with the amp.
 
Quote:

 
Thank you for your reply, and you have confirmed what I had always thought.
 
I am indeed going for the AD8620 if I buy the amp (might be today

), simply because the only high impedance headphones I own is the AKG K 701, which for anyone who knows, is not that high at all. Indeed, it's rating of 62 Ω is fairly efficient, though it is difficult to drive.
Since I use my AKG K 701's so much, I prefer transparency and openness to my music, but I do like good bass. The K 701's are pretty good at this, though with my current amplifier, the NuForce Icon, it is not as detailed as my Etymotic Research ER-6i's using my JDSLabs Custom cMoyBB v2.02.
The major selling point is the battery, portability, slimness, recharge functions, gain settings, and the Bass Boost switch. Oh, and the minimalist aesthetics; even if the Batch 2 faceplate's aren't as good as John and co like, they are still awesome looking (from the pictures I have seen), and the possibilty of getting the Batch 3 faceplate's in Feb for free (excluding the shipping cost) makes it a very good investment.
 
So, for that reason alone, the AD8620 is essential to make my AKG K 701's really sing.

That transparency and power from the opamp will eclipse my NuForce Icon.
More so, the bass boost feature that I use in my Custom cMoyBB v2.02 (exclusively for the ER-6i's) is also present on the C421, and looking at the spec sheet, its better than my cMoyBB; this means I can use it on my K 701 on some recordings, such as Trip-Hop and Electronica (some rock, but depends on recording), and turn it off for almost everything else, especially classical. In fact, I hate using the BB feature when using my K 701's with NIN records, as it does not work well, but I guess that's more to do with the cMoy amp; I shall test if the C421 will fair better, but I bet that Trent Reznor's music, especially his Ghost I-IV and recent soundtracks (with Atticus Ross) will sound better without the BB switched on. If I were to listen to, say, Daft Punk, then the BB will be switched on, because "Daft Punk is playing in my house, my house".

The BB will also be used for the K 701's when I play films from my PC using Dolby Digital (Asus Xonar D2X and CCCP with Media Player Classic- Home Cinema), and/or when I play Xbox 360 games (non-multiplayer or co-op) using my, poor, but cheap and decent, TurtleBeach EarForce DSS 7.1 Dolby Digital sound interface (if I play MM or co-op, I use a stereo set-up and my JohnBlue AudioArt JB3 speakers).
 
BB will probably not be on most of the time with my UE Triple.Fi 10 Pro's (I doubt it needs the boost) except if I use it for films and Xbox 360 games (as described above), though I will test if this is necessary. Otherwise, the AD8620/Triple.Fi 10 pairing will be pretty awesome.

 
As for the ER-6i, I cannot imagine not using the BB at all, and I love how it retrieves detail from music, but it is very fatiguing. The AD8620 and BB will really help me use the ER-6i's for longer, as is the case with my Burr-Brown OPA2227P Custom cMoyBB v2.02 with BB on.

 
Yeah, I don't need the other op-amps in the C421, as I can have the best of both worlds; transparency, and bass boost. WIN!

 
I like the idea of owning another C421 with a different op-amp (such as your AD8066), but instead, I might put that money towards owning the Objective2 from JDSLabs.com as part as my desktop headphone amplifier instead. That is for later (maybe sometime this year), but for now, the C421 has my heart.

 
Do you think my usage plans will work for my headphones and media?

 

 

[TheOneInYellow]

Ha ha, sounds like you have created a combination to make a subwoofer for your headphones! Lots of fun.
 
As for your set-up, its great that you have gone for a modular based DAC (as they advance so very quickly these days) and a decent desktop amp. I just use my NuForce Icon, which was great at the time of purchase, but a future amp is on the cards, and the Objective2 is within a reasonable budget and looks to be a great price/performance/build/SQ.
 
As for LOD/cables, I did own a female LOD dock and a nice male-to-male interconnect 3.5mm from ALO Audio, but the LOD dock broke a while back, so I have been using the crappy iPod output for a few years. No biggie, as I hardly use my portable rig. In fact, I had thought bout purchasing some Moon-Audio.com's LOD cables (either Blue or Silver Dragons V3), but decided against it on the basis of usage (very small), cost, and shipping costs (almost the same as the damn LOD cable!). Instead, I went for a super cheap but great FiiO L9 LOD cable; yes not the worlds greatest LOD, but it will do me fine, as it has some good reviews, seems to be well made (not comparing to expensive LOD's), and will do the job. I have no intention of spending ludicrous amounts of cash on something I will hardly use. If, however, I bought something like the ALO Audio AlgoRhythm Solo or the Fostex HP-P1, then I shall invest in a nice LOD. Until then, the FiiO L9 will more than suffice
 
Finally, and here is the BIG NEWS, I have purchased a C421 Amp today with the AD8620 opamp (just over 30 mins ago), and I beat the shipping cuttoff point by 5 mins! LOL!
Got my tracking number too, so yay!!!
 
Unfortunately, getting there was hard, but I can't discuss the details of why it took so long for my bank and PayPal to play nice, especially after I got my wages today. Seriously, so bad that I logged a complaint.

 
There is a lot of stuff that I want to, and allowed to (with some exceptions), write about here on this thread, mainly centring around the emails between John Seaber and myself, and how he and his staff are simply AWESOME! This word will be overused a lot!
However, it's 23:09 here in the UK and I need sleep (especially after the farce above), so I shall do this tomorrow.
 
Good night everyone!

 

[2000impreza]

I seem to be having charging problems with the C421. While plugged in the orange charging led never turns off. Also once I pull the C421 off the usb charger and power on the unit, the red(low battery) indicator lights up right away. Does anyone else have this problem? I sent JDSlabs a e-mail this morning so I guess I'll wait for their response. I'm trying to decide if it is worth shipping this back to JDSlabs since I'm in Canada.

 

[gelocks]

No problems charging so far!
John responses are fairly quick and his support is top-notch so maybe they can help you out without having to return it!
 
Good luck and let us know how it goes!!

 

[i_djoel2000]

the unofficial review from headfonia is up: http://www.facebook.com/notes/headfoniacom/jdslabs-c421-impressions/316049348439769

 

[adlkevin]

exactly experiencing the same problem as yours, i have contacted with john and was told that most likely battery faulty connection. he will kindly help u out

 

[F900EX]

I'm getting all excited about amp's again .......
 
These reviews are like a meal that look's fantastic but taste like .......

 
 
Joking aside, sooo temped

 

[jseaber]

Quote:

exactly experiencing the same problem as yours, i have contacted with john and was told that most likely battery faulty connection. he will kindly help u out

 
You two ordered the same week, and reported the same issue within 24 hours of each other. There are a number of possibilities, but we'll wait to receive and inspect both amps before drawing any further conclusions. The charging circuit is a solid reference design from Texas Instruments. It's worked flawlessly in our prototypes since 2009 and it's the one circuit which hasn't changed since then. So, I expect this to be a manufacturing flaw limited to a small number of units in the pre-production run. c421 has been in customers' hands since October without issue. Thus, it's highly unlikely to be a circuit design error.
 
Final production will be performed by a large contract shop capable of performing in-depth testing on every single circuit board. Whatever this issue may be, it will be resolved by final release next month.
 
Also, we're ceasing shipments of "temporary" c421's due to low inventory. New preorders will ship in late February.
 
Edit: We've received one of three units with this known issue (not great, but not alarming out of 100). It seems to be caused by excessive solder paste beneath the charging IC. We'll make minor manufacturing adjustments, and the next batch will be tested more thoroughly and inspected by X-Ray.

 

[adlkevin]

Apart from the minor bugs in the preorder status, the listening experience that c421 gives me is really impressive. I have owned ALO RX MK2 and TTVJ SLIM before, I can just say that the c421 beats them all, no matter the potential of the bass or the rich mid, yet its resolution is even better than a harman kardon home amp, that it gives you as many detail as the songs have, really, believe it or not, you will be able to hear many more instruments at the background than before. You can try yourself, it just likes a successor of TTVJ SLIM, but please do remember that the c421 is only at half price of it!
 
In conclusion, I recommend the c421 to you wholeheartedly, you will never regret even if you already own an expensive amp, or for a beginner, the c421 is certainly be your first choice. I am not a professional, but I just want to share my excitement with it to all head fier.
 
In deed, it also provides you excellent customer service and after-sale support with quick respond and good communication, that I never expereince in online shopping. You will probably understand why I say that if you are a owner of Arrow amp...
 
Now, let us wait for the final product to come out, it must the best buy in 2012!

 

[Naim.F.C]

Can't speak for this product yet, as I am yet to try it, but I can say, based off my experiences with John regarding the cMoyBB, a simple, cost effective amp that for me was comparable to amps many times it's cost, I have full faith in any new product JDS develops. It will be tremendously interesting to see how the impressions for the c421 pan out. I'm almost certain this amp will deliver in spades sonically and anticipate it to be among the best, for it's given price point, especially if the cMoyBB was anything to go by.
 
For anyone looking for ultimate value for money, go JDS. In the mean time, great to see John on top of things with respect to ironing out any minor teething issues along the way. If I hadn't spent so much on new amps/DAC's in recent times, I'd have already jumped all over this beauty.