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Announcing Codename “c421" from JDS Labs

post #1 of 11
Thread Starter 

 

Announcing Codename “c421″

We’re past due on several announcements, but not due to a lack of content. In fact, we’ve been exceptionally busy this spring.

After returning from Silicon Valley last week, I was thrilled to see a package from Advanced Assembly at my office. Inside were two recently completed “c421″ prototype headphone amplifiers:

A first look at codename c421, Prototype II (v0.84) - May 2011

Project History

Initial experimentation of c421 unofficially began in 2008, about a year after release of the cMoyBB. The goal at the time was to create a buffered headphone amp resistant to GSM interference. However, I ultimately spent 2008 and early 2009 designing microcontroller boards, a huge 4-layer, 2.4GHz quadrature modulator testbed, and miscellaneous audio circuits while finishing my BSEE. JDS Labs was still a very small company, so those first prototypes were stuffed into a box for many months.

Driving to a New Years celebration on December 31, 2009, for whatever reason, a new power supply circuit popped into my head. I jotted the idea onto paper as soon as I got home. Half a dozen Texas Instruments and Linear Technology evaluation boards later, we arrived at the first draft c421 schematic. An eager mechanical engineer contacted us around this time and custom enclosure design began immediately. By December 2010, the first c421 prototype PCB was in hand (pictured below).

c421, Prototype I (v0.83) - December 2010

The new ground/supply circuitry conjured almost a year earlier turned out flawlessly, but like many first draft designs, the PCB was far from perfect. With some trace chopping, I persuaded c421 v0.83 to behave, according to the oscilloscope.

Unfortunately, my ears were not pleased with the new opamp circuit (designed purely in LTSpice). For a mid-range headphone amplifier, it sounded weak, slow, and generally mediocre. Back to the drawing board!

Prototype II: Success

Starting over, I tweaked the opamp circuit and tried something very different: A triple-ground, dual-channel topology. Five “channels” in all. For a while, it seemed crazy. The 4-layer PCB would be split into a chaotic mess, but hey, it was worth a shot.

We replaced the opamp, the power IC, and added two more chips. Practically every R/C/L component on the board changed and the layout grew significantly more dense.

c421, Prototype II (v0.84) - May 2011

Pending Release

I am pleased to announce that c421, Prototype II is a tremendous success! Typically I judge audio equipment by its capability to invoke the pilomotor reflex (hair raising brilliance). c421, Prototype II absolutely delivers. It’s powerful, fresh, and exciting to listen to.

Features and pricing will be announced closer to release, although much of the feature-set can be inferred from the photographs. And when might c421 be released? As soon as we jump through production hurdles, of course. Stay tuned!

post #2 of 11

I'm a sucker for them slimlines, keep us informed!!!

post #3 of 11

If this provides more power and better sound than the cMoy, then this will replace my T3. I'm looking forward to it. 

post #4 of 11
Thread Starter 

Have you look at ibasso touscan's spec's?  here it is:

 

 

iBasso PB1 Toucan

Portable Balanced Headphone Amplifier

Main features:
- 25.2V voltage swing, the highest voltage swing among portable Amplifiers
- Up to 1400mW output power
- Takes Balanced and Single End inputs, and provides Balanced and Single End outputs
- 2-Setting gain switch for impedance matching 
- Rechargeable battery pack
- New case surface finish, we call it pulverization finish
- More than 20 hours play time
- Measures 55*24*81mm, and weighs 140g
- ALPS quad potentiometer, Hirose connector, Switchcraft jack, gold-plated PCB, Vishay high grade capacitors and resistors inside
- Comes with charger, leather pouch, 3.5 to 3.5 interconnect, rubber feet, and warranty card


Quote:
Originally Posted by zero7525 View Post

If this provides more power and better sound than the cMoy, then this will replace my T3. I'm looking forward to it. 



 

post #5 of 11

Awesome man! :) I'm really interested too

post #6 of 11

According to the blog over at JDS Labs this promising new portable amp should be available to pre-order any day now. Anyone else here gonna take the plunge?

post #7 of 11
Quote:
Originally Posted by Hi-fi Wigwammer View Post

According to the blog over at JDS Labs this promising new portable amp should be available to pre-order any day now. Anyone else here gonna take the plunge?


Depends on the price tag :P

 

post #8 of 11

Yep, no official pricing yet. Last I heard JDS were saying it would be under $175.

post #9 of 11

Still correct!

 

Enclosures shipped this morning. The pre-order page will go live as soon as we inspect production quality.

 

Quote:
Originally Posted by Hi-fi Wigwammer View Post

Yep, no official pricing yet. Last I heard JDS were saying it would be under $175.



 

Reply
post #10 of 11
You don't know how tempted I am, to get this just for my earbuds. :P
post #11 of 11

Preorder is live - discussion link here: http://www.head-fi.org/t/575633/jdslabs-c421-preorder-is-live

 

Price is $169 or $165 depending on opamp ordered.

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