[Makiah S]

Quote:

nothing, John is a great guy, he will replace the ferrite for free, you pay for the black end plates and you can get free custom engraving with every order.
 
mine went from portugal to the US and back in less than 2 weeks, amazing service and super quick. also the work is top notch, i highly reccomend JDS Labs.

yea I liked the cMoy Bb i got from them, you think he would replace the Ferrites for me if I palced an order for a NEW c421 Vlack edition? Like asked for the replacement on the new model as opposed to sending it back later

 

[putente]

Quote:

yea I liked the cMoy Bb i got from them, you think he would replace the Ferrites for me if I palced an order for a NEW c421 Vlack edition? Like asked for the replacement on the new model as opposed to sending it back later

 
 
The new "Black Edition" c421 already comes with the ferrite mod. See here: http://blog.jdslabs.com/?p=419

 

[ostewart]

sorry for any confusion, All new orders will ship with Black end plates, and the 2Ohm Ferrite, i sent mine in for the upgrade as i had the older version.

 

[LoveKnight]

How does changing ferrite from 11Ohm to 2Ohm can improve the sound? Not sure because I am not a technical guy but with my old version C421 and with my HD598, I use low gain and turn up the volume knob just a little bit but it is very loud to my ears. Maybe with this changing C421s will drive more IEMs better but it could be a disadvantage to fullsize headphones. Do you guys think so?

 

[ostewart]

It has to do with output impedance and damping factor. It is better for low impedance headphones and IEMs.

High output impedance used with low impedance phones can change the whole frequency response...

The output impedance should never be higher than 1/8 of the headphones impedance.

 

[Mutnat]

Yeah I'm really debating if I should send mine in for the ferrite swap or not... my HD25's are 70 ohm, so > 8x the 10.5-11 ohm of the original ferrite.  That said, I can't say that I've really noticed any sloppiness to the low end that would call out for greater dampening.  But maybe I just don't know what I'm missing.  Tough call.  I'd hate to be without the amp for a while to do it.  And shipping from John to Vancouver BC (Canada) is quite slow, so I'd likely be without the amp for the better part of a month considering the full round-trip.  Or pay a fortune for expedited shipping.  Neither option is especially appealing.
 
A NOTE TO PEOPLE DOING THE FACEPLATE SWAP with the black plate kit... be careful with your screws!  I was trying to but still accidentally let one get away on me and it got lost in my deep shag area rug .  Admittedly, this was a bad place to be doing the work.  But those screws are very tiny!  So be careful.  That said, if you DO happen to lose one, and you have a PS3 around, you can steal one of the screws from the PS3 controller to tide you over till you get a proper one. It's not a perfect cosmetic match with the other C421 screws, but it does fit despite being a bit longer and seems to work okay.
 

 

[RingingEars]

Quote:

be careful with your screws!  I was trying to but still accidentally let one get away on me and it got lost in my deep shag area rug .  Admittedly, this was a bad place to be doing the work.  But those screws are very tiny!  So be careful. 
 

Get yourself a good magnet like an old speaker magnet and go over the area. You'll find it.

 

[Makiah S]

Quote:

It has to do with output impedance and damping factor. It is better for low impedance headphones and IEMs.
High output impedance used with low impedance phones can change the whole frequency response...
The output impedance should never be higher than 1/8 of the headphones impedance.

I suppose that would be good, but for a 250 Ohm can would the lower impedeance unit work better... you'd think the 10 ohm ouput would drive them better

 

[ostewart]

It has nothing to do with power or driving them better, only about controlling the driver better

 

[Makiah S]

Quote:

It has nothing to do with power or driving them better, only about controlling the driver better

Well Power=Control unless there's to much
 
The issue I have now with my cMoy is there is not enough power to properly control the driver, granted it doesn't sound bad but it still needs a little more juice to sound like it should
 
So I'm wondering if the c421 has the extra power needed for the superior control oh a High Impedance can

 

[ostewart]

Ok, not controlling the driver better, just damping the driver better

 

[Mutnat]

Quote:

be careful with your screws!  I was trying to but still accidentally let one get away on me and it got lost in my deep shag area rug
 

 
Quote:

Get yourself a good magnet like an old speaker magnet and go over the area. You'll find it.

 
Actually I emailed John and, true to his excellent customer service reputation, he replied very quickly, and has already put a couple of screws in the mail to me, on the house.  John's a great guy to deal with, for sure!

 

[RingingEars]

Quote:

 
 
Actually I emailed John and, true to his excellent customer service reputation, he replied very quickly, and has already put a couple of screws in the mail to me, on the house.  John's a great guy to deal with, for sure!

Nice.
I've heard nothing but good things coming from JDS, performance and CS wise.
Now that the C421 went all black I'm pretty sure this will be my next amp.

 

[Makiah S]

Quote:

Ok, not controlling the driver better, just damping the driver better

Indeed, now what is damping x[ 

 

[Bill-P]

Sent my C421 in for a ferrite change. To my pleasant surprise, I got an upgrade to black faceplate as well.
 
 

 
 

 
And she sounds phenomenon!