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The DX90 by iBasso . . . Sound impressions . . . . . . . New Firmware, 2.5.1 . . . - Page 98

post #1456 of 3032
Quote:
Originally Posted by Dave74 View Post


I wonder if an amp performs better at higher volume settings as opposed to lower volume settings?

From what I understand, you don't want to push the amp to high volumes as it intrudes distortions.  Amps become non-linear as push it high.  But then again, I've seen a graph of SS source and it showed under .01% distortion until clipping at certain voltage point(or volume point), which means there is not enough power to support.  Headphones also reacts to high power push, it starts to distort more at louder volumes.

 

I believe the DX90 LO is directly from the DAC, and it's probably like the software volume control on your computer.  I think the right balance of the two is most optimal.  

post #1457 of 3032
Quote:
Originally Posted by SilverEars View Post

From what I understand, you don't want to push the amp to high volumes as it intrudes distortions.  Amps become non-linear as push it high.  But then again, I've seen a graph of SS source and it showed under .01% distortion until clipping at certain voltage point(or volume point), which means there is not enough power to support.  Headphones also reacts to high power push, it starts to distort more at louder volumes.

I believe the DX90 LO is directly from the DAC, and it's probably like the software volume control on your computer.  I think the right balance of the two is most optimal.  

Ok. Thanks. I think I will try 245-250 on the DX90 then and lower the volume on the Pure ii.
post #1458 of 3032
Quote:
Originally Posted by headwhacker View Post
 

For maximum SNR using LO, volume must be set to 255. However, with very sensitive phones where I don't get much range with the amp's volume pot I set the DX90 volume at 245 - 250.

 

 

Quote:
Originally Posted by SilverEars View Post
 

From what I understand, you don't want to push the amp to high volumes as it intrudes distortions.  Amps become non-linear as push it high.  But then again, I've seen a graph of SS source and it showed under .01% distortion until clipping at certain voltage point(or volume point), which means there is not enough power to support.  Headphones also reacts to high power push, it starts to distort more at louder volumes.

 

I believe the DX90 LO is directly from the DAC, and it's probably like the software volume control on your computer.  I think the right balance of the two is most optimal.  

Trying the LO on the DX90 set to 250 now with the Pure ii and Dita's and the bass is definitely fuller and more dynamic sounding.  I tried switching back and forth between 220 and 250 while adjusting the volume on the P2, and I think it is a big improvement.  In my post in the Pure ii thread I said I found the bass a little lacking compared to the Pico Power, now it is great.

 

Edit..Actually I think the soundstage seems improved as well as the bass dynamics.  It really lets this amp strut its stuff:)

 

Thanks headwhacker and SilverEars:beerchug: 


Edited by Dave74 - 6/14/14 at 2:03pm
post #1459 of 3032
Quote:
Originally Posted by Dave74 View Post
 

 

 

Trying the LO on the DX90 set to 250 now with the Pure ii and Dita's and the bass is definitely fuller and more dynamic sounding.  I tried switching back and forth between 220 and 250 while adjusting the volume on the P2, and I think it is a big improvement.  In my post in the Pure ii thread I said I found the bass a little lacking compared to the Pico Power, now it is great.

 

Thanks headwhacker and SilverEars:beerchug:

What I said about taxing the amp doesn't apply to p2 as the p2 has plenty of power even at low gain setting.  You probably won't even turn the volume knob up that high so I guess around 250 is good?  Not sure how all this volume level for dac chip with volume control LO works.  

post #1460 of 3032
Quote:
Originally Posted by SilverEars View Post
 

What I said about taxing the amp doesn't apply to p2 as the p2 has plenty of power even at low gain setting.  You probably won't even turn the volume knob up that high so I guess around 250 is good?  Not sure how all this volume level for dac chip with volume control LO works.  

At 250 on the DX90 I have the volume know on the Pure ii set at around 10:00-11:00 with low gain setting.  At 200-230 on the DX90 I had the volume know set between 12:00 and 2:00.

post #1461 of 3032

In general, for an amp with analog volume control the sweet spot is between the 10:00 - 2:00 position. An analog pot seems to perform best anywhere at this range. Especially when you listen at very low volume with a multi-BA phones, it minimize if not eliminate channel imbalance.

post #1462 of 3032

I'm liking the DX90's LO more than the X5 LO, contradictory to what I was predicting.  Amazingly ODAC is the the most precise.  I know that for sure because when I pair with the Vorz, it sounds more clear, ridiculously clear.  I hear so much subtle details, it's exactly what I'm looking for.

post #1463 of 3032

iBasso didn't include a burn-in cable for nothing. As per my own experience and others as well, DX90 does evolve SQ-wise after hundreds of hours of burn-in. My DX90 changed noticeably after 200 hrs.

 

It was at it's worst for me out of the box.

post #1464 of 3032
Quote:
Originally Posted by headwhacker View Post
 

In general, for an amp with analog volume control the sweet spot is between the 10:00 - 2:00 position. An analog pot seems to perform best anywhere at this range. Especially when you listen at very low volume with a multi-BA phones, it minimize if not eliminate channel imbalance.

Usually because it's a compromise between less resistance in the circuit vs how hard it's driving later stages. Wide open should be best when/if there is a difference and later stages aren't stressed. With the DX90 floating point V control, resistance is a non-issue and only how later stages respond to gain are to be considered.


Edited by goodvibes - 6/15/14 at 12:20am
post #1465 of 3032

I have also noticed a change in time with the DX90, the reason of the burn-in cable is in the wikipedia

 

"Aging is fastest near the beginning of life of the component, and the device stabilizes over time."

 

Capacitance instability

http://en.wikipedia.org/wiki/Capacitor

 

Edit : A bit more about the capacitor used in the DX90, they are from the Nichicon Gold series, specially developed for audio, they are used in pair and there are four in all.

http://www.nichicon.co.jp/english/products/pdfs/e-fw.pdf

 

I think the DX90 is like a good wine that improve over time ;)


Edited by Migou67 - 6/15/14 at 1:10am
post #1466 of 3032

is the unit "burning in" even when using LO, or only with phones?
 

post #1467 of 3032

@heans The capacitor are used to stabilize the power supply of the TI634 buffer chip used by the HO amplifier stage.

post #1468 of 3032

The fellows in the our local Hong Kong and China DAP forums are usually more critical on Chinese brand DAPs. We generally have fewer brand worshipers here and opinions are more objective.

 

The common consensus in the Hong Kong and Chinese forums is the DX90 LO is very good and the DX90 HO is just "ordinary'... to the point that there is already fellow removing the TI634 BUF chips (to reduce current drain) and converting the HO to Balanced LO similar to that of RWAK120-B (http://www.um-audio.com/forum.php?mod=viewthread&tid=1333&extra=page%3D1) :

 


Edited by borrego - 6/15/14 at 2:50am
post #1469 of 3032
Quote:
Originally Posted by borrego View Post
 

The fellows in the our local Hong Kong and China DAP forums are usually more critical on Chinese brand DAPs. We generally have fewer brand worshipers here and opinions are more objective.

 

The common consensus in the Hong Kong and Chinese forums is the DX90 LO is very good and the DX90 HO is just "ordinary'... to the point that there is already fellow removing the TI634 BUF chips (to reduce current drain) and converting the HO to Balanced LO similar to that of RWAK120-B (http://www.um-audio.com/forum.php?mod=viewthread&tid=1333&extra=page%3D1) :

Thanks for this as I don't frequent the Chinese forums because of my limited Chinese.  :D  Or shall we say no Chinese? I guess it's being used as a portable balanced as it was capable from the getgo with it's two signal paths, but ibasso didn't want to put a balanced connector.

 

I like to know what they think of the X5 HPO.

post #1470 of 3032
Quote:
Originally Posted by borrego View Post
 

The fellows in the our local Hong Kong and China DAP forums are usually more critical on Chinese brand DAPs. We generally have fewer brand worshipers here and opinions are more objective.

 

The common consensus in the Hong Kong and Chinese forums is the DX90 LO is very good and the DX90 HO is just "ordinary'... to the point that there is already fellow removing the TI634 BUF chips (to reduce current drain) and converting the HO to Balanced LO similar to that of RWAK120-B (http://www.um-audio.com/forum.php?mod=viewthread&tid=1333&extra=page%3D1) :

 

 

This pictures can be from a DX50? The capacitor have a gold color on the DX90 board :

 

 

Source : http://headphoniaks.com/blog/?p=807&preview=true


Edited by Migou67 - 6/15/14 at 4:32am
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