JDSLabs C421 Preorder is live...
Feb 1, 2012 at 1:24 AM Post #106 of 692

nihaz

Head-Fier
Joined
Jul 20, 2011
Posts
61
Likes
12


Quote:
yeah its like it hasnt fully engaged yet at low volumes, i do assume its limitations with these dial things instead of going for a pot. There no imbalance that i know of beyond that point though.
 


 


Thanks for confirming... I thought I was going deaf in one ear or something...
 
It's not that big of an issue for me because its the volume is very low when it kicks in... It's gone by the time i reach my normal listening volume so I'm a happy chappy
L3000.gif

 
 
Feb 1, 2012 at 1:59 AM Post #107 of 692

PANGES

1000+ Head-Fier
Joined
Jan 4, 2010
Posts
1,132
Likes
47
Lucky! My normal listening levels are right at where the imbalance is.. But that's just because my UE4's are really sensitive. I don't have that issue with my Ety ER4S. 
 
... btw: If you guys have a pair of ER4S, or can get your hands on some, I'd advise you to try them out with the C421. IMO, they pair up really really well.
 
Quote:
Quote:
yeah its like it hasnt fully engaged yet at low volumes, i do assume its limitations with these dial things instead of going for a pot. There no imbalance that i know of beyond that point though.
 


 


Thanks for confirming... I thought I was going deaf in one ear or something...
 
It's not that big of an issue for me because its the volume is very low when it kicks in... It's gone by the time i reach my normal listening volume so I'm a happy chappy
L3000.gif

 



 
 
 
Feb 2, 2012 at 3:57 PM Post #108 of 692

jseaber

Member of the Trade: JDS Labs
Joined
Jan 6, 2010
Posts
542
Likes
175


Quote:
Lucky! My normal listening levels are right at where the imbalance is.. But that's just because my UE4's are really sensitive. I don't have that issue with my Ety ER4S. 
 
... btw: If you guys have a pair of ER4S, or can get your hands on some, I'd advise you to try them out with the C421. IMO, they pair up really really well.
 


 
 


 
We're reducing low gain in the final batch, which should lessen this imbalance. Gain of 3.5x was a bit much for the sensitive pot when combined with high sensitivity IEM's.
 
I'm sure it will be asked: The gain resistors are very expensive and time consuming to replace by hand (not free, sorry).
 
Feb 2, 2012 at 4:29 PM Post #109 of 692

PANGES

1000+ Head-Fier
Joined
Jan 4, 2010
Posts
1,132
Likes
47


Quote:
Quote:
Lucky! My normal listening levels are right at where the imbalance is.. But that's just because my UE4's are really sensitive. I don't have that issue with my Ety ER4S. 
 
... btw: If you guys have a pair of ER4S, or can get your hands on some, I'd advise you to try them out with the C421. IMO, they pair up really really well.
 


 
 


 
We're reducing low gain in the final batch, which should lessen this imbalance. Gain of 3.5x was a bit much for the sensitive pot when combined with high sensitivity IEM's.
 
I'm sure it will be asked: The gain resistors are very expensive and time consuming to replace by hand (not free, sorry).


About how much will it run? If this is possible, it may still be worth it for me. 
 
 
 
Feb 2, 2012 at 6:30 PM Post #110 of 692

nihaz

Head-Fier
Joined
Jul 20, 2011
Posts
61
Likes
12


Quote:
About how much will it run? If this is possible, it may still be worth it for me. 
 
 



+1
 
Would be keen to have this performed if the price is reasonable.... as I will be getting some sensitive IEMs that will probably benefit from this procedure...
 
Thanks for responding to this thread too John! It's nice to see companies stand by and provide support for their products :)
 
Feb 2, 2012 at 7:39 PM Post #112 of 692

Yuceka

1000+ Head-Fier
Joined
Aug 15, 2010
Posts
1,122
Likes
76
Location
UK
So do we know when the first batch will be ready if I order one right now?  
 
Feb 2, 2012 at 8:23 PM Post #113 of 692

jseaber

Member of the Trade: JDS Labs
Joined
Jan 6, 2010
Posts
542
Likes
175
 

So do we know when the first batch will be ready if I order one right now?  

 
Our fabricators are on track to deliver by the end of this month (28-29th). We'll ship within 24 hours.
 
Quote:
About how much will it run? If this is possible, it may still be worth it for me. 
 
 


Parts, labor, and return shipping for gain modification would total about $15. Note that going from 3.5x to 2.5x is about a -3dB change, which is fairly small. I point this out because we're seeing similar concerns from our O2 customers, and the default gain is already 2.5 there.
 
I didn't want to move from an analog to a digital pot in c421, but the trend over the past few years has been towards lower impedance, higher sensitivity headphones and these increasingly do not pair well with analog pots assuming low listening levels. To achieve excellent channel balance in such setups, one must either must forgo line-level input (i.e., reduce source volume), use a large potentiometer or stepped attenuator (not portable friendly), or go for a device with a digital pot (usually lower fidelity).
 
Venturing off topic. Lowering gain will help slightly, but forgoing an LOD is the best fix *if* the headphone output of your source isn't too bad. Again, this is a non-issue with larger cans.
 
Feb 2, 2012 at 9:17 PM Post #114 of 692

PANGES

1000+ Head-Fier
Joined
Jan 4, 2010
Posts
1,132
Likes
47


Quote:
 

So do we know when the first batch will be ready if I order one right now?  

 
Our fabricators are on track to deliver by the end of this month (28-29th). We'll ship within 24 hours.
 
Quote:
About how much will it run? If this is possible, it may still be worth it for me. 
 
 


Parts, labor, and return shipping for gain modification would total about $15. Note that going from 3.5x to 2.5x is about a -3dB change, which is fairly small. I point this out because we're seeing similar concerns from our O2 customers, and the default gain is already 2.5 there.
 
I didn't want to move from an analog to a digital pot in c421, but the trend over the past few years has been towards lower impedance, higher sensitivity headphones and these increasingly do not pair well with analog pots assuming low listening levels. To achieve excellent channel balance in such setups, one must either must forgo line-level input (i.e., reduce source volume), use a large potentiometer or stepped attenuator (not portable friendly), or go for a device with a digital pot (usually lower fidelity).
 
Venturing off topic. Lowering gain will help slightly, but forgoing an LOD is the best fix *if* the headphone output of your source isn't too bad. Again, this is a non-issue with larger cans.


Oh, so even if I have this done, it still might not help me..? :frowning2:
 
Is there any chance of an impedance switch in the future (like the Practical Devices XM6.) That was the only thing that made the amp usable for me, because without it, I had a similar issue that I'm having now. 
 
 
 
 
 
Feb 2, 2012 at 11:39 PM Post #115 of 692

jseaber

Member of the Trade: JDS Labs
Joined
Jan 6, 2010
Posts
542
Likes
175
 
Quote:
Oh, so even if I have this done, it still might not help me..? :frowning2:
 
Is there any chance of an impedance switch in the future (like the Practical Devices XM6.) That was the only thing that made the amp usable for me, because without it, I had a similar issue that I'm having now. 
 
 
 
 


It might help, it might not. Depends on how far away your ears want to be from the "bad" spot at the start of the potentiometer.
 
No impedance switch will be added. Adjusting input or output impedance dramatically alters signal behavior.
 
EDIT: Listening to c421 right now with the new 2.5x gain through 16 ohm, [size=small]108 dB/mW[/size] IEM's. Balance at low volumes is excellent, in my opinion. Better than many RK097's we've shipped! I'll probably regret this, but anyone who has a c421 in a temporary case may send their amp in for a complete v1.01 upgrade (new case + gain change).
 
Feb 3, 2012 at 8:31 PM Post #116 of 692

F900EX

100+ Head-Fier
Joined
Apr 4, 2011
Posts
273
Likes
18
Jseaber -
 
I know this might be a difficult question, but between the 2 Amps, O2 and your own c421, what are the biggest differences when it comes to the sound they give out.
 
Feb 4, 2012 at 11:34 AM Post #117 of 692

syphen606

100+ Head-Fier
Joined
Jan 18, 2012
Posts
102
Likes
15


Quote:
Jseaber -
 
I know this might be a difficult question, but between the 2 Amps, O2 and your own c421, what are the biggest differences when it comes to the sound they give out.

 
On reading various thoughts around the internet, it seems they have similar sounds but the C421 is an ultra portable compared to the O2. The few comparisons are that the O2 may have the edge (ever so slightly) on sound.   You do gain the bass boost feature with the C421 which is nice if you like filling out the lows with a particular set of really bright phones that you like.   If your handy and understand electronics, there is mods to ADD a bassboost setup to an O2 which has been posted on DIY audio.
 
I'll let you know when I finish my O2.   I have the enclosure and all internal parts sitting on the bench but am missing the PCB and faceplate (Seemingly lost in mail purgatory as my friend who orders his after me go his earlier this week!  Really hoping it shows up next week.)
 
 
Feb 4, 2012 at 4:51 PM Post #118 of 692

Jonasklam

500+ Head-Fier
Joined
Nov 26, 2009
Posts
535
Likes
12
Hi guys,
 
I noticed some of are interested in purchasing this amp, but don't want to wait for shipping to begin.
 
I am welling to sell mine if any1 is interested? I have hardly used it and selling because I need money :/
Any takers? Send me a PM :)
 
I am in EU though
 
Feb 7, 2012 at 2:38 PM Post #119 of 692

Mutnat

100+ Head-Fier
Joined
Sep 7, 2009
Posts
258
Likes
16

Might be tempting were you not in the EU. 
 
PS: I think it's important for people listing theirs for sale (or giving their impressions) to also mention which opamp they ordered their amp with.
 
Quote:
 
I am welling to sell mine if any1 is interested? I have hardly used it and selling because I need money :/
Any takers? Send me a PM :)
 
I am in EU though



 
 

Users who are viewing this thread

Top