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Apr 11, 2014 at 5:37 AM Post #2,536 of 14,084
Perhaps at this point it's safe to say the first batch of DX90 will only ship as early as Monday, If nobody has gotten any confirmation yet especially for those guys who are in HK.
 
Apr 11, 2014 at 5:38 AM Post #2,537 of 14,084
  As certainly many of you, I'm deciding between the FiiO X5 and the iBasso DX90.
My portable headphone right now is the Shure SE846, a 9ohm impedance phone that needs low output impedance on the dap and a lot of current, not much load needed.
Both the X5 and the DX90 have less then 1ohm impedance, thats good. But how about the output current? Is the output stage comparable to a headphone amp made for iems, like the slim?
 
Thanks

 
So this is just a lot of guess work since I own neither at this point:

I think the output current of the X5 is 460mW into 16ohms (according to Fiio). I'm assuming Fiio capped it at 460mW, so it should still be that at 9ohms, which is A LOT for an IEM. It's almost half a watt. Your 846 will be thundering.
 
The voltage gain on both the DX90 and X5 is 2.8Vrms (according to spec). Assuming this is true, and ignoring that Chinese dude's measurements the DX90 has the potential to match the X5 in terms of current, but I'm not sure if Ibasso capped it lower than Fiio. I think they might have. If you're looking for max current I think X5. If you're looking at other sound quality factors, perhaps DX90?
 
Obvioiusly this is just a guess and nothing more than preliminary musing based on nothing. What's ironic is that the DX90 actually has the bigger voltage swing, which is 10v p-p, while the X5 does >8V p-p. Not sure why Ibasso capped it so low? perhaps to achieve those nice THD numbers?
 
To be perfectly honest I'm pretty much baffled by Ibasso's numbers. Why?
Because according to them the DX90 does +/- 5V,
which is 10 Vp-p
which means it should be doing 3.54Vrms at 32ohms and giving us 391mW at 32ohms (more than the X5)
Instead they say on High gain it's doing 2.8Vrms, but this Chinese dude is measuring it at 2.1Vrms. I'm assuming they capped the max current for headroom? Fiio's numbers actually align perfectly with their stated peak to peak values and what the dude measured, in fact it exceeds the numbers by a little bit.
 
Apr 11, 2014 at 6:25 AM Post #2,539 of 14,084
   
So this is just a lot of guess work since I own neither at this point:

I think the output current of the X5 is 460mW into 16ohms (according to Fiio). I'm assuming Fiio capped it at 460mW, so it should still be that at 9ohms, which is A LOT for an IEM. It's almost half a watt. Your 846 will be thundering.
 
Thiis is not current, it's power.  Divide the 16ohms from the 460mW and sqrt it.  
 
The voltage gain on both the DX90 and X5 is 2.8Vrms (according to spec). Assuming this is true, and ignoring that Chinese dude's measurements the DX90 has the potential to match the X5 in terms of current, but I'm not sure if Ibasso capped it lower than Fiio. I think they might have. If you're looking for max current I think X5. If you're looking at other sound quality factors, perhaps DX90?
 
This is not gain, voltage output at a gain.
 
Obvioiusly this is just a guess and nothing more than preliminary musing based on nothing. What's ironic is that the DX90 actually has the bigger voltage swing, which is 10v p-p, while the X5 does >8V p-p. Not sure why Ibasso capped it so low? perhaps to achieve those nice THD numbers?
 
To be perfectly honest I'm pretty much baffled by Ibasso's numbers. Why?
Because according to them the DX90 does +/- 5V,
which is 10 Vp-p
which means it should be doing 3.54Vrms at 32ohms and giving us 391mW at 32ohms (more than the X5)
Instead they say on High gain it's doing 2.8Vrms, but this Chinese dude is measuring it at 2.1Vrms. I'm assuming they capped the max current for headroom? Fiio's numbers actually align perfectly with their stated peak to peak values and what the dude measured, in fact it exceeds the numbers by a little bit.
 
Yes, it should be around 3.5Vrms around most load since output impedance is less than .1ohms.  I get 110mA for current.  W is power, not current, but yeah 391mW is what you should get at that load of 32 ohms assuming it's can provide 10Vpp at max volume at max gain.  The low output impedance maximizes the power to the load so most load should get close to maximum.  

 
Apr 11, 2014 at 6:39 AM Post #2,542 of 14,084
i ordered the 2nd hours it put out for sale not a single email... Hiaz... did we paid for express shipping?
 
Apr 11, 2014 at 6:41 AM Post #2,543 of 14,084
I think Chinese guy is measuring the maximum voltage and power output that hits the THD 1% mark, not what maximum it's capable of.
 
This means, X3, X5, and DX100 are more capable of driving less sensitive headphones at high volume with less distortion, that is if the headphones needs that much power.
 
Apr 11, 2014 at 6:56 AM Post #2,545 of 14,084
  I think Chinese guy is measuring the maximum voltage and power output that hits the THD 1% mark, not what maximum it's capable of.
 
This means, X3, X5, and DX100 are more capable of driving less sensitive headphones at high volume with less distortion, that is if the headphones needs that much power.

So the reason why he is checking for what max V and W it can output at 1% THD is because theoretically, less than that is not audible.
 
Apr 11, 2014 at 6:59 AM Post #2,546 of 14,084
   
Obvioiusly this is just a guess and nothing more than preliminary musing based on nothing. What's ironic is that the DX90 actually has the bigger voltage swing, which is 10v p-p, while the X5 does >8V p-p. Not sure why Ibasso capped it so low? perhaps to achieve those nice THD numbers?
 

 
James from Fiio said the the X5 is +/- 6v. So maybe the 8v p-p on their specs page means they capped it at 8v for headroom, while ibasso with +/- 5v capped it lower than the 8v of X5 which would explain the outcomes.
 
Apr 11, 2014 at 7:21 AM Post #2,548 of 14,084
  James from Fiio said the the X5 is +/- 6v. So maybe the 8v p-p on their specs page means they capped it at 8v for headroom, while ibasso with +/- 5v capped it lower than the 8v of X5 which would explain the outcomes.


Ah makes sense then... so Fiio is giving us the numbers where they capped it and Ibasso is giving us numbers before cap. I wish Ibasso would give us the numbers where they capped as that would reflect what it was capable of.
 
Assuming Ibasso and Fiio are using the same ratio for headroom then the DX90 should have an actual voltage swing of +/- 3.33V with rms of 2.356, which is closer to what the Chinese dude measured. Hmm... now I think I "get it".
 

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