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JDSLabs C421 Preorder is live... - Page 9

post #121 of 692
Quote:
Originally Posted by gelocks View Post


Good luck on your finals!!! :-p

 

And yep... it seems the battery only goes for like 10-12 hours...

It's not bad... but their Cmoy lasted almost 20 on the same setting (i.e. I use my player+amp continuosly at work for up to 10 hours a day...)

 

Still find the amp a bit bright so I think this is part of the "sound signature" with the opamp I

bought it. It's not bad though and it's driving my D5000s well! Right now listening to Fiona Apple's Extraordinary Machine... great record

and everything sounds crisp and clear with good instrument separation. Bass response is really good too.

 

BTW, put up some Deadmau5 again this time with bass boost... uffff... I've never felt headphones vibrating this mad

without producing any kind of distortion whatsoever... not sure if it's due to the capability of the amp, the headphones or both!
 

 


Hey gelocks

My first Head-fi post...exciting stuff! :)

 

So I've recently acquired the D5000 (loving them so far...have just over 100 hrs burn in and they just keep getting better. Bass is just a tad heavy, but worth it for the overall sound sig.).

Which opamp option did you go for? Am getting the C421 and having trouble deciding between the 8620 and 2227? You mentioned the amp being a bit bright...would you choose the same opamp again?

 

Thanks in advance!

 

post #122 of 692
Quote:
Originally Posted by theotherbk View Post


Hey gelocks

My first Head-fi post...exciting stuff! :)

 

So I've recently acquired the D5000 (loving them so far...have just over 100 hrs burn in and they just keep getting better. Bass is just a tad heavy, but worth it for the overall sound sig.).

Which opamp option did you go for? Am getting the C421 and having trouble deciding between the 8620 and 2227? You mentioned the amp being a bit bright...would you choose the same opamp again?

 

Thanks in advance!

 


Hello!

Welcome to head-fi! ;-)

 

I went with the 8620. And yes, it is a bit bright but I believe it pairs rather well with both the Denon D5000s and Beyer 770 Pro 80 (which I mostly use with the amp). The amp as-is is a huge step-up from the JDSLabs CmoyBB, the NuForce Icon Mobile and the other cheapo Cmoy I had!

 

Would I choose it again? Probably as I don't know how the 2227 sound but some people find that the latter is more spacious and provides more mids. Mike from Headfonia put up his impressions on:

 

http://www.facebook.com/note.php?note_id=316049348439769

 

and he raves about 2227 (he didn't really like the 8620... :-p).

 

Thing is that the opamp is not replaceable ( :-( ) so you have to take a chance to see which one you like! You could always order two and sell the one you like less! lol ;-)

 

Good luck!

And keep enjoying those D5000s! (they're sweeeeeet!!!)

post #123 of 692

I've also got the AD8620 version and thought it bright at first. Been using it regardless mostly with my HD25 for the past 1.5 months and a bit with my HD580 in just the past couple weeks. I think the treble has settled a bit (or I'm just getting used to it). My only real comparison is my PA2V2 amp, which is decidedly warm compared with the c421. But maybe the 8620 is just neutral to slightly treble forward, rather than really "bright." Bass is still really nice and tight, though.

 

I do wonder about the OP2227 version, and hopefully will have a chance to listen to one. 

post #124 of 692

Shameless plug, but if anyone doesn't want to wait for the preorder batch to come out, I've posted my JDSLabs C421 with the AD8620 opamp up for sale.

 

http://www.head-fi.org/t/596207/jdslabs-c421

post #125 of 692

My experiences of back-to-back rolling between the 2227, 8066 and 8620 all come from a JDSLabs CmoyBB.  Out of all of them, I preferred the 8620. It was a little 'brighter' if you will then the 2227 but I just found it clear and detailed.   I went ahead and ordered my C421 in 8620 and have had it for a month and a half now. Really loving it.  Sound quality it is just about on par with the O2 (bass boost off) but with the added benefit of fitting in my pocket.     My HD650's simply sound amazing with the C421 and I'll admit that I like the sound of them with the bass boost on... a feature the O2 lacks in default configuration.

 

Safe bet, the 8620 will work for you.

post #126 of 692

..

post #127 of 692

Curious--how does the C421/8620 compare to the PA2V2 with the HD25's?  I know the PA2V2 is fairly well regarded, and the main thing that stopped me from trying it was the dimensions didn't seem very pocketable (would have preferred flatter even if bigger in the other dimensions, like the C421).  I'm waiting on a C421/2227 based on Headfonia Mike's recommendation, and because the HD25 is a mildly-bright can to begin with and I worried it might be too bright with the 8620. 

 

Quote:
Originally Posted by JRoMan View Post

I've also got the AD8620 version and thought it bright at first. Been using it regardless mostly with my HD25 for the past 1.5 months and a bit with my HD580 in just the past couple weeks. I think the treble has settled a bit (or I'm just getting used to it). My only real comparison is my PA2V2 amp, which is decidedly warm compared with the c421. But maybe the 8620 is just neutral to slightly treble forward, rather than really "bright." Bass is still really nice and tight, though.

 

I do wonder about the OP2227 version, and hopefully will have a chance to listen to one. 



 

post #128 of 692

Our PCB assembler says v1.01 boards will be delivered Feb. 29th. Final cases are supposed to ship on the 28th. We'll have them overnight enough to cover preorders.

 

It's a super tight schedule, but I'm finally happy with the progress. We added a chamfer to smooth out the rough panel edges (picture is only a sample, not final!):

 

Bumpon_02.jpg

 

Quote:
Originally Posted by Mutnat View Post

JDS store now says orders will ship between Feb 29th and March 9th.  I hope mine ships on the earlier end of that range!



 

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post #129 of 692


Thanks for the update, John!  That chamfer (I had to look it up on Wikipedia, so I learned a new word today!) sounds like it will add some nice polish to the appearance, and it's great to hear things are on schedule.  I can barely wait to try mine!

post #130 of 692


Looks great!  Can't wait to get the new case.  What are the 1.00 to 1.01 changes?

 

 

Quote:
Originally Posted by jseaber View Post

Our PCB assembler says v1.01 boards will be delivered Feb. 29th. Final cases are supposed to ship on the 28th. We'll have them overnight enough to cover preorders.

 

It's a super tight schedule, but I'm finally happy with the progress. We added a chamfer to smooth out the rough panel edges (picture is only a sample, not final!):

 

Bumpon_02.jpg

 



 



 

post #131 of 692
Quote:
Originally Posted by Mutnat View Post

Curious--how does the C421/8620 compare to the PA2V2 with the HD25's?  I know the PA2V2 is fairly well regarded, and the main thing that stopped me from trying it was the dimensions didn't seem very pocketable (would have preferred flatter even if bigger in the other dimensions, like the C421).  I'm waiting on a C421/2227 based on Headfonia Mike's recommendation, and because the HD25 is a mildly-bright can to begin with and I worried it might be too bright with the 8620. 

 



 


I'm in my cubicle with the HD25 and both the PA2V2 and c421/8620. I've listened to a handful of tracks back and forth. For reference, they included:

  • Adele, "Rolling in the Deep"
  • The Civil Wars, "Poison and Wine"
  • Ella Fitzgerald, "Bewitched, Bothered, and Bewildered"

   

and a more rocking song for good measure (well, at the end, at least)

  • The Black Keys, "Little Black Submarine"

 

I like using female vocals as it's one of the things I focus on when listening to music, so hence it is more or less my reference when evaluating headphones and the like. These tracks also include some of the following: tambourine, cymbal, piano, and guitar, which I used as an indicator of the brightness or treble emphasis. I do honestly think the c421 has smoothed out since I got it in late December. The PA2V2 I've had basically a year, so it is well run in. As I alluded to before, the PA2V2 is tilted more to the warm side and I'm guessing might be closer to the smoothness of the c421/2227 that Headfonia Mike has mentioned in his postings on FB. The 8620 on the other hand is tilted more to the upper-mid/treble, so there is a little more air under the vocals. The PA2V2 is a little more "weighty" and grounded with the vocals, and if you want to call that "smoother," I think that is what I hear. The c421 is a bit more forward and clear in the upper mid and treble (if you want to say "detailed" I can go with that - I'm still coming to grips with some of this terminology, can you tell?). It is more forward with the guitar riffs on the Black Keys' track and the piano on some of the others. The other way to look at it is there is generally a little more right hand piano emphasis on the c421/8620 and more left hand piano emphasis on the PA2V2. I think the PA2V2 might play a notch bassier, but the c421 may have a little more punch, if that makes any sense. Flipping the bass boost on the c421 brings it up like 4 notches, and it doesn't really bleed into and affect the midrange, so the vocals actually still sound about the same.

 

To wrap up, I wouldn't say the c421/8620 & HD25 combo is TOO bright, but it might not be favorable to everyone's ears, depending on your tolerances. A month ago, I was leaning towards it being too bright. Also realize I've only had the HD25 about as long as the c421, so there may be some synergystic breaking in going on, who knows.

 

I did have a chance to listen to some Grado SR80i and 125i with my c421 a few weeks ago and that was not really an ideal combo. It brought out a lot of sibilance, esp. with the SR80i's.

 

Lastly, the form factor of the c421 wins over the PA2V2, though the battery life of the PA2V2 (I'm running Sanyo Eneloops) is amazing. Hope that wasn't too long winded.



Forgot to add, while I didn't notice that much this time around, in previous comparison (using Shure SRH840) the PA2V2 plays slower, while the c421 plays a quicker pace. It was actually quite interesting to hear it, because it is a somewhat abstract thing to comprehend. I found that intriguing since many reviews of the PA2V2 I've read praise it for its PRaT. It makes some sense, though, because of the darker/warmer signature that it would sound slower.
Edited by JRoMan - 2/17/12 at 4:48pm
post #132 of 692


All manufacturing changes, except for the reduced gain discussed above [settled on a low gain of 2.3x]. Much of this will come across as technical speak to non-engineers:

 

• Reduced low gain from 3.5x to 2.3x
• Manufacturing: Changed battery jack J2 from thru-hole to SMT
• Manufacturing: Decreased solder paste beneath charging IC, U2
• Manufacturing: Changed PCB finish from HASL to ENIG (better QFN solderability)
• Manufacturing: Changed PCB panel from 4-up to 3-up
• Manufacturing: Moved tab-routed mousebits inwards
• Manufacturing: Added 0.3mm reinforcement vias to SMT audio jack pads

Quote:
Originally Posted by syphen606 View Post


Looks great!  Can't wait to get the new case.  What are the 1.00 to 1.01 changes?

 


@JRoMan : You must have Mike's ears. Might want to switch to the OPA2227.

 

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post #133 of 692
Quote:
Originally Posted by jseaber View Post


All manufacturing changes, except for the reduced gain discussed above [settled on a low gain of 2.3x]. Much of this will come across as technical speak to non-engineers:

 

• Reduced low gain from 3.5x to 2.3x
• Manufacturing: Changed battery jack J2 from thru-hole to SMT
• Manufacturing: Decreased solder paste beneath charging IC, U2
• Manufacturing: Changed PCB finish from HASL to ENIG (better QFN solderability)
• Manufacturing: Changed PCB panel from 4-up to 3-up
• Manufacturing: Moved tab-routed mousebits inwards
• Manufacturing: Added 0.3mm reinforcement vias to SMT audio jack pads


@JRoMan : You must have Mike's ears. Might want to switch to the OPA2227.

 


Thanks John!  Its gracious of you to share the on going changes of the C421.

 

I'm fine with the gain settings where they are in my pre-order model (8620 w/3.5x). So this change is of little effect to me based on my current headphone inventory.

 

I guess an electrical engineering background has me interested in the changes..

 

  I understand the ENIG soldering, (I haven't opened the case yet to see which components are QFN yet.. Soon enough with the new case) considering the smt components used and the scale your looking at producing (Hopefully), as well as reducing to 3-up from a cost POV if the 4th plane is not in use. Ditto to the mousebits. These changes just seem cost/quality related from a production stand point.
 It looks like the other changes revolve around mechanical strength of the jacks for both battery and audio jacks. Has there been an observeable history of issues or failures with on going use of these in the v1.00 models?

 

And on a side note, Sennhesier HD650's & C421 with AD8620 is a real winning combo off a good DAC.


Edited by syphen606 - 2/16/12 at 9:08pm
post #134 of 692

Ordered cmoys x2 then O2 x2 from John, now I might be itching to buy this one hahaha, so far my dealings with JDSLabs is pretty awesome.

post #135 of 692

Just to confirm understanding, 4-up and 3-up refer to the number of circuit boards on a production panel (not number of layers). All c421's are 4-layer boards. The first run was arranged in a 4-up panel:

 

c421_v100_4up.jpg

 

Without delving into a long-winded explanation, we ended up with 3 boards on the v1.01 panel. Higher board cost, but easier assembly.

 

HASL = Hot Air Surface Leveling. ENIG = Electroless Nickel Immersion Gold. HASL is the standard PCB finish with very low cost. However, and this is a lesson we paid for dearly in 2011, HASL boards have an uneven surface only good for through-hole and large SMT components (SO-8, etc.). This can result in tiny solder bridges beneath QFN parts--usually on 2-5% of boards. And this creates fun problems which arise after a board heats up for the first time, like charging circuits not charging, and misbehaving status LEDs. wink_face.gif ENIG raises board cost, but produces a flat surface, great for fine pitch parts. The high cost of implementation is partly why you don't see high performance QFN parts on sub-$100 amps and DACs.

 

All battery jack failures were caught prior to shipment. The failure was either present, or it was not (will not occur over time). This was a mechanical strength issue with ground vias coupled to J2, not a jack strength problem. Easily resolved.

 

As with any device employing SMT audio jacks, a few customers managed to rip a jack from the board. It hasn't been a major issue, but we're minimizing the possibility.

 

 

Quote:
Originally Posted by syphen606 View Post


Thanks John!  Its gracious of you to share the on going changes of the C421.

 

I'm fine with the gain settings where they are in my pre-order model (8620 w/3.5x). So this change is of little effect to me based on my current headphone inventory.

 

I guess an electrical engineering background has me interested in the changes..

 

  I understand the ENIG soldering, (I haven't opened the case yet to see which components are QFN yet.. Soon enough with the new case) considering the smt components used and the scale your looking at producing (Hopefully), as well as reducing to 3-up from a cost POV if the 4th plane is not in use. Ditto to the mousebits. These changes just seem cost/quality related from a production stand point.
 It looks like the other changes revolve around mechanical strength of the jacks for both battery and audio jacks. Has there been an observeable history of issues or failures with on going use of these in the v1.00 models?

 

And on a side note, Sennhesier HD650's & C421 with AD8620 is a real winning combo off a good DAC.



 

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