[davtse]

We all know that cowon can put out some amazing players, but they all suffer from the same problem(at least the newer models), bass roll off.
this mod removes the small 220uf caps and replaces them with 470uf caps. my version adds some 25ohm resistors as well, feel free to experiment with your own combinations.

sorry for the blur pic but this was the only one i could find. credits anythingbutipod.com
the 220uf caps are the ones circled in white.

there is no place for the larger caps, so after removing them, we soldered thin wire extensions for the cap mod. thin wires will fit better because the caps are located under the screen. thicker wires will not allow the screen to snap close to the pcb board.

modifying the casing for the new caps


 
and finally the end product

FR curve generated from RMAA

Original before mod(credit dfkt)                   After mod. Typo on the entry, the purple curve should be the control unloaded one.

 

[Tjj226 Angel]

I honestly don't know what that graph means, but I can take a pretty accurate guess and say you improved your player by a whole heck of a lot. I am pretty new to the whole circuit board thing, but what are the odds of taking a 40 dollar cheapo music player and modding it to be an audiophile music player?

 

[davtse]

To be honest, the cowons use pretty decent dacs(wolfson) and amplifiers in their players. Their one fault would be that either due to space constraint or just to save manufacturing costs, they use some pretty small value capacitors, which in the case of the d2 results in massive bass rolloff and congestion.
The graphs just show how the bass response has improved post-mod and with different IEMs. Pre-mod when paired with the jh16s, the bass was bloated and a lot of the sub bass was missing.

 

[davtse]

Just had a break through today.
complete bassrolloff fix with rockbox + mod.
 

 

[hoichi]

Funny how there's so little replies, I think the mod is very interesting.
 
May I ask a few noob questions?

• What do the resistors do?
• What happens if I use bigger caps? (I could borrow some off an old video card.)
• What if I take polymer or ceramic caps? Those could be pretty small.
• What's the Rockbox mod you mentioned?

 

[kcduke]

I used tantal capacitors from broken motherboard:
http://i003.radikal.ru/1409/eb/351eca1403ee.jpg
They are compact and I was able to place them in the other side of the board. Glued them on a thin 2-sided adhesive tape:
http://s019.radikal.ru/i618/1409/dc/90c1b950ec85.jpg

 

[bootdsc]

Nice hardware hack, yeah i know this is a dead thread but who cares.

 

[kcduke]

Well, I just read the topic and decided to do the same modification on my player. But I did not want to cut it so. And so the remembered about tantalum.
P.S. Sorry for my English.


 

 

[bootdsc]

How do you like the sound after modding? Should have added more punch to the low bass. Great find with those surface mount capacitors, they are so compact you wont even know its modded.
 
Your English is fine, we try not to use so,the,but or and to often because you end up with a run-on sentence. Still your English is better then a lot of Americans i know.

 

[kcduke]

  How do you like the sound after modding? Should have added more punch to the low bass.

Maybe a little effect. But maybe it's placebo.