[CoiL]

babs, did You also have LO capacitors Nichicon FW 100uF 10V as stock? You didn`t change Your unit LO capacitors?
Replacing LO capacitors with littlebit larger value is ok? If they fit of course (didn`t measure clearance).
Somehow I thought they were also 220uF 10V. But seeing they are nichicons, probably going to leave them in place. 
 
Btw, my DX50 batch nr. is E23 (little white iBasso sticker), 20130809 (on PCB). 
 
Edit: 
 
First contestant up and running - Panasonic FM 220uF 10V
 
Initial impressions are, that bass is more powerful (hits pretty hard) and tighter, drums sound also very powerful, clean and have natural "reverb", highs are more sparkly but mids kind of laid back. Front/middle of soundstage seems littlebit more foward but same time separation and soundstage reach seems also improved but not sure how much because I cut off my stock Jovial caps legs to desolder better and can`t compare atm. Have to solder leads back to stock caps later.
Going to let FM`s burn in for 2 days at least. These are just first impressions and doesn`t mean anything actually, they are going to change.
 
Edit: Ok, this is final list of caps I`m going to test:
 
* Nichicon FG 100uF 10V (going to change LO caps and maybe test them on HO also)
* Nichicon FW 220uF 10V 
* Nichicon KW 220uF 10V 
* Panasonic FM 220uF 10V
* Panasonic FC 220uF 10V 
* Panasonic FR 220uF 10V
* VISHAY BC 220uF 10V
* Panasonic AM 330uF 10V
* Nichicon FW 100uF 10V
 
Edit:
* Nichicon KA 220uF 10V
* Nichicon KA 100uF 6.3V
* Nichicon KA 100uF 16V (size fits)
* Nichicon SW 220uF 6.3V
 
babs, I`m not so clever in electronic circuits as You and I have a question - in case of DX50 HO caps, is it ok to use littlebit larger value capacitors (330uF instead 220uF) ? In case of Aune T1 it was ok to use larger value but with DX50 I`m not sure. I`m really interested how Panasonic AM (Audio) perform since they have little larger capacitance for the same size and good specs.

 

[ptjw99]

Correct me if I'm wrong at any point as I've read a lot on this recently but am still new to it all; I believe, from the formula F = 1/(2 x pi x C x R)) where C is capacitance and R is load impedance i.e your headphones, that the higher the capacitance, the lower the frequency response cutoff, meaning the lower frequencies are passed to your headphones, so e.g for my HD-25s with 70ohm impedance:
 
1 / ( 2 * 3.142 * 440uf * 70) gives 5.167hz so anything below this will not be going to your headphones, but I read that it is usually higher than this by a factor of up to 10 (i.e 5.167 x 10 = 51.67hz) because of tolerances and other factors. Thus the bigger the cap the lower the frequencies can be passed, but a bigger cap also causes less transparency in sound, and also a louder POP when you turn on the player and when the capacitor energizes/discharges (unsure of which) to your headphones, and too big a pop can ruin your headphones too. 
 
Thus you shouldn't go mad and select the biggest capacitor value possible to get the lowest possible cutoff frequency, while at the same time you should also not select too small a value such that you lose details on the low frequencies.

 

[CoiL]

So, basically, when I want less bass with my HP, then 100uF should be better? I know I can play with the values but the thing I`m concerned about is how changing those values affects circuit board and other components on it.
Those capacitors have +-20% tolerance anyway as much info I`ve found on stock Jovials. So, little larger or smaller value should be ok.
About pop, I always remove cable first and then turn player off.

 

[ptjw99]

So, basically, when I want less bass with my HP, then 100uF should be better? I know I can play with the values but the thing I`m concerned about is how changing those values affects circuit board and other components on it.
Those capacitors have +-20% tolerance anyway as much info I`ve found on stock Jovials. So, little larger or smaller value should be ok.
About pop, I always remove cable first and then turn player off.

By the logic I posted, assuming I'm right, then in theory a smaller cap value will result in attenuated bass due to the frequency cutoff being higher, so yeah less bass comes with less capacitance. Circuit wise, as long as the rating of the capacitor is the same or greater then there should be no problem with more capacitance at least for these output coupling capacitors..

on a side note: the KW caps I'm using do seem to be somewhat brighter sounding than the Jovials now after a few days of listening.. I can hear sharper details especially in songs that have electric guitar riffs.. they sound less muddy and more detailed than before.

 

[CoiL]

ptjw99 , how are KW mids? It seems FM`s are also brighter and clearer but like in case with Aune T1 cap testing I found them littlebit lack in mids section. Wish we had right size ELNA SilmicII`s, would go straight this way.

 

[DMinor]

For the LO mod, you guys should try removing the DC coupling caps entirely and just send the signals with the 2.5 volts to amp capable of compensating for this much DC bias.
 
You may be surprised by the clean and transparent sounding from eliminating the caps. Again, just make sure your amp can handle the DC bias and cancel it at output to the phones.
 
Did anyone say the DX90's LO has no DC coupling bias? If true, is there any DC offset from its LO?

 

[CoiL]

I`m not going to use external portable amp with DX50, so staying with caps. 
Updated my test-bed littlebit so I could still carry it with me (rubber ribbon goes over caps to stop them coming off) 

 
 

 

[babs]

The DC of LO output is 2.5V before the caps
There is also a 100 Ohms resistor in series, so there is no purpose to use bigger caps, these outputs are designed for high impedance load (external amp)

 

[CoiL]

Anyone tried those Nichicons? http://uk.farnell.com/nichicon/uka1a221med1td/capacitor-alum-elec-220uf-10v/dp/2094116
 
Want to order them but haven`t found good place inside EU or legit internet reseller yet.

 

[babs]

I buy all my caps on Digi-Key:
http://www.digikey.ca/product-detail/en/UKA1A221MED1TD/493-4632-1-ND/2787059

 

[CoiL]

Yeah, I could buy from Mouser also but delivery costs 10x more than 6pcs capacitors. Haven`t checked digikey shipping price yet.
But I`m very interested trying those Nichicon KA series caps.
 
Edit: If someone know place where those KA caps are being sold in EU then please let me know. Atm all places offer from US storage and delivery prices are insane!
 
Edit: Yes! Found online UK shop that sells those KA caps. Ordered some 100uF ones as well. Total price with airmail ~8£ ...nice!

 

[shagrathborgir]

ca you please post where we can get them in EU?what's the uk seller?
http://ca.mouser.com/new/nichicon/Nichicon-Audio-Caps/  some info regarding nichicon caps

 

[shagrathborgir]

what's the name of the shop?

 

[CoiL]

Do more Your own "research" using internet search. Sorry if this sounds harsh for You but things that are in limited small stock - not willing to give link so easily

 

[CoiL]

Little update...

 
Btw, got some of my ordered capacitors and by initial impressions my 3 favourite are Panasonic FC, Panasonic AM and quite a surprise for me - Vishay BC 038 RSU series. Just fell asleep half hour ago while listening to The Mars Volta - Amputechture 

 Really enjoying the sound with these caps. Got to burn in all those caps while my Nichicon KW/FW/FG/KA are on the way. So far worst cap soundwise has been Panasonic FM (lack of mids and weird soundstage). Next up - Panasonic FC ...lets see if I fall asleep again while enjoying music 

 

 
Edit: One thing for sure imho - stock Jovials have been beaten by Panasonic FC & Vishay BC 038 RSU. This is subjective of course and depends on Firmware being used & headphones/IEMs too.