[goodvibes]

   
Ok. Can you explain why I don't hear current noise through my IPAD 4 powered by the same "sub standard" Apple 5V power supply? Or you are implying the DX90 digital volume control is superior, and yet being easily affected by a dirty PS?
 
I admit I don't understand: the very huge difference of belief and "knowledge" between the "Portable Source Gear" and "Dedicated Source Components" of head-fi
 

You're not even asking the right questions. The Ipad has more post supply smoothing because it's intended to be used with it's supply. Try a high current battery supply on the DX90 and your issue should disappear. That said, it's now occurred to me, though unlikely, that the charging circuit could conceivably induce some noise as well but no way to know until a 5v battery is connected to the USB port to find out. 

 

[borrego]

  In this case, using the volume control in the DAC is better than using an outboard dig control upstream because the inboard one is extremely well engineered, bit perfect and avoids an additional a2d-d2a conversion processes of a later one upstream. Using a later analog control may be preferred but it's no slam dunk that there's benefit. In this case, it would be difficult to incorporate and in your scenario it would see large signal at it's input so low level tracking could be an issue.
 
The noise isn't coming from the DAC. The larger signal level of full on is masking the noise of the opamps when the PS is dirty or there is a ground loop etc. The noise is not a product of the DAC V control. 

 
You can read all my previous posts. I have never said the noise come from the DAC built-in volume control circuit because it is not well engineered.
 
In my case:
(i) the amount of current noise generated by my "dirty" IPAD 4 5V supply is always the same -> N
(ii) the signal strength coming out from the OPA1602 I/V conversion with volume level set at 255 -> S
 
When using the DX90 DAC built-in digital volume control, at any volume settling lower than the max volume level 255, the signal coming out from the OPA1602 (after I/V conversion) is lower than full strength: -> s
 
Using an external amp with analog or digital volume control at later stage, allow me to run "S" instead of "s" from the point after the OPA1602, which give better signal to noise ratio in the later 2 stages of OPA1611 and BU634 amplifications.
 
Can you see now how S/N is greater than s/N?
 
All you said can be true if the 9018K2M can drive the headphone directly like the all in one chip in IPAD 4. Unfortunately it is not the case.

 

[329161]

   
The lesson there my friend is don't blindly follow impressions when making a purchase decision. Always do a demo and comparison.
 
One man's rubbish is another man's treasure. the guy's opinion you mentioned who compared DX90 to a 1K rig is as valid as your opinion that DX90/DX100 is crap.

The problem with brands like iBasso, Hisound , and Vmoda, is that they get hyped to the rafters here at Head-fi. It gets you thinking that all that hyperbole justifies pulling the trigger. The other problem is - bricks and mortar stores don't sell these products in Sydney, so it's not always possible to audition these things first hand. Got to look outside of Head-fi for reviews as well, I guess.
Either that, or wait about a year for all the hype to die down. Then the real (more measured opinions ) come out.

 

[goodvibes]

   
You can read all my previous posts. I have never said the noise come from the DAC built-in volume control circuit because it is not well engineered.
 
In my case:
(i) the amount of current noise generated by my "dirty" IPAD 4 5V supply is always the same -> N
(ii) the signal strength coming out from the OPA1602 I/V conversion with volume level set at 255 -> S
 
When using the DX90 DAC built-in digital volume control, at any volume settling lower than the max volume level 255, the signal coming out from the OPA1602 (after I/V conversion) is lower than full strength: -> s
 
Using an external amp with analog or digital volume control at later stage, allow me to run "S" instead of "s" from the point after the OPA1602, which give better signal to noise ratio in the later 2 stages of OPA1611 and BU634 amplifications.
 
Can you see now how S/N is greater than s/N?
 
All you said can be true if the 9018K2M can drive the headphone directly like the all in one chip in IPAD 4. Unfortunately it is not the case.

Of course I can but you were really unclear when blaming the V control. I addressed both the gain and V control issues so it's covered. The issue isn't the circuit that works as intended but when additional noise is induced by an outside influence. You're putting the cart before the horse. That the noise is constant and being masked by the signal at larger volume settings would indicate it's more generated at later stages anyway. Those that may be after and unaffected by any type of V control. I just don't get blaming a device that works properly until an external noise inducing circuit is attached. Find a quieter PS or use a battery.

 

[borrego]

  You're not even asking the right questions. The Ipad has more post supply smoothing because it's intended to be used with it's supply. Try a high current battery supply on the DX90 and your issue should disappear. That said, it's now occurred to me, though unlikely, that the charging circuit could conceivably induce some noise as well but no way to know until a 5v battery is connected to the USB port to find out. 

 
So you are now saying the IPAD 4 has better circuit design than the DX90, and yet the DX90's implementation of DAC built-in volume control is better? It is definitely possible: iBasso implements such a "superior" DAC built-in volume control design and let down by its poor charging circuit. Very smart design indeed.

 

[headwhacker]

 
The problem with brands like iBasso, Hisound , and Vmoda, is that they get hyped to the rafters here at Head-fi. It gets you thinking that all that hyperbole justifies pulling the trigger. The other problem is - bricks and mortar stores don't sell these products in Sydney, so it's not always possible to audition these things first hand. Got to look outside of Head-fi for reviews as well, I guess.
Either that, or wait about a year for all the hype to die down. Then the real (more measured opinions ) come out.

 
If you order direct from iBasso, they have a 14-day money-back guarantee starting from the day you receive your order. You can try it first and return it if you are not satisfied. I almost did it with DX50, iBasso already sent me the instruction where to send it but in the end I kept it because the lineout with amp won me over and still cheaper than say an AK100 then. 

 

[329161]

   
If you order direct from iBasso, they have a 14-day money-back guarantee starting from the day you receive your order. You can try it first and return it if you are not satisfied. I almost did it with DX50, iBasso already sent me the instruction where to send it but in the end I kept it because the lineout with amp won me over and still cheaper than say an AK100 then. 

Ye, I guess I shouldn't complain with a policy like that. My point is- don't always believe the hype in these forums. For eg, the VModa M100 only got 3/5 stars in What Hifi. Go into the M100 thread and it's pretty much 5 star all the way. Try to say otherwise, and all the Vmoda fanboys jump all over you. Audiophiles are a funny bunch.
 
Anyways, I'll end my rant there.

 

[headwhacker]

For those who are on tight budget, the DT235 pairs well with DX90. Doesn't sound like a 50 USD headphone to me. I guess I'm at home with Beyerdynamic signature.

 

[goodvibes]

 
The problem with brands like iBasso, Hisound , and Vmoda, is that they get hyped to the rafters here at Head-fi. It gets you thinking that all that hyperbole justifies pulling the trigger. The other problem is - bricks and mortar stores don't sell these products in Sydney, so it's not always possible to audition these things first hand. Got to look outside of Head-fi for reviews as well, I guess.
Either that, or wait about a year for all the hype to die down. Then the real (more measured opinions ) come out.

I quite like my ANV 3 and DX90 but respect your opinion as well. I certainly don't like everything that gets touted here but I also don't think it's all hype either. I liked my ak120 but understand the value ratio isn't tops. The DX90 is likely better overall but the AK still had a musicality and nice color about it's sound that I could see someone preferring. Didn't care for the X5 which many love. I think the IPhone beats all the other smart phone's sonics but isn't as good as my DAPs. We're all different and that's fine.

 

[headwhacker]

 
Ye, I guess I shouldn't complain with a policy like that. My point is- don't always believe the hype in these forums. For eg, the VModa M100 only got 3/5 stars in What Hifi. Go into the M100 thread and it's pretty much 5 star all the way. Try to say otherwise, and all the Vmoda fanboys jump all over you.
 
Anyways, I'll end my rant there.

 
True, I never buy any headphone without demoing it first. I was intrigued by M100 as well when it was released and by the praises it received on it's thread. But when I tried it, meh. A 50 SGD DT235 is much better imo.

 

[goodvibes]

   
So you are now saying the IPAD 4 has better circuit design than the DX90, and yet the DX90's implementation of DAC built-in volume control is better? It is definitely possible: iBasso implements such a "superior" DAC built-in volume control design and let down by its poor charging circuit. Very smart design indeed.

Never said anything of the sort but feel free to read in whatever you like.

 I think the V control appropriate for this purpose but never called it "superior" (do you understand hoe to use quotes?). I also never called the DX90 charging circuit inferior and said it unlikely the issue with a clean 5V supply. Just prefer to be open minded. Why would anyone spend the money on a DX90 and be critical of it when running it off of a what should be a $5 PS, blaming the DAP when said supply makes it noisier? Dude, if you want to be an audiophile, don't use a wall wart. 

 

[borrego]

  Of course I can but you were really unclear when blaming the V control. I addressed both the gain and V control issues so it's covered. The issue isn't the circuit that works as intended but when additional noise is induced by an outside influence. You're putting the cart before the horse. That the noise is constant and being masked by the signal at larger volume settings would indicate it's more generated at later stages anyway. Those that may be after and unaffected by any type of V control.

 
Is my cart really in front of my horse?
 
Good circuit design (charging circuit in this case) and implementation (volume control in this case) should take practical user environment into account. Does the DX90 include its own dedicated 5V power supply in the package? Does iBasso specify a "HiFi" 5V power supply as a purchase option? Do you really think I should go out to buy and build a Class A liner power supply (http://www.audio-gd.com/Pro/diy/PSU2013/PSU2013EN.htm) to use with the DX90 while charging, and yet still insist the DAC level volume control implementation is a perfectly good design?
 
Facts:
(i) I hear current noise through the built in DX90 volume control set at 160 normal/usual listening level
(ii) The noise problem can be "fixed" if I set the DX90 volume control at max 255 level, and listening through an external amp.
 
I draw conclusion that the DX90 DAC level volume control implementation is not good enough. That's my impression. And this is the impression thread. Anything unusual ?

 

[329161]

   
True, I never buy any headphone without demoing it first. I was intrigued by M100 as well when it was released and by the praises it received on it's thread. But when I tried it, meh. A 50 SGD DT235 is much better imo.

Ye, I thought 3/5 stars was pretty accurate actually...but we shouldn't go off topic I guess.

 

[329161]

 
Ye, I thought 3/5 stars was pretty accurate actually...but we shouldn't go off topic I guess.

PS the M80 only got 4/5 in WhatHifi...over here it was about 6/5

 
 
On the other side of the coin- they rate Beats Dr Dre quite highly (4/5 for the Beats and Beats Pro), same with some Bose products- these are people who are paid (valued) for their opinions. And who do I listen to? The geeks (of which I'm one) here at Headfi.

 

[Caruryn]

As far as value to performance ratio dx90 is a bargain,beaten only by clip.Fiio x5 is probably along the same lines.No phone or even sony players up to F800 series can compete in terms of detail,clarity,soundstage bass control,neutrality and dynamics.An iphone with a $400 amp may sound better or not,again depending on iem or headphone.I agree though about the hyperbole part on some threads here on head fi.