borrego said:

 
Yes, I was referring to the PK1. What I meant "does not have enough voltage swing" was not saying there was no sound or stupidly low volume. I was referring to the sound being congested and lack of dynamic. Switching to LINE OUT + Arrow 4G to drive the PK1 makes a big difference (bigger difference than compare to drive the EPH-100 with the Arrow 4G

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This is exactly what I was asking about. How did you know that DX90 has not enough voltage swing for the PK1. Arrow 4G has +/- 5.5V (11V) of voltage swing according to it's spec and as far as I know DX90's can deliver +/-5V PP total.

headwhacker said:

This is exactly what I was asking about. How did you know that DX90 has not enough voltage swing for the PK1. Arrow 4G has +/- 5.5V (11V) of voltage swing according to it's spec and as far as I know DX90's can deliver +/-5V PP total.

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I don't think the DX90 can deliver +-5V PP under load. See the erji.net forum test results below at 32ohm/THD 1%
 

Actually I am glad the DX90 does not use voltage regulator to raise the power supply voltage to the amp section. Doing so will likely introduce more noise given the relatively primitive power supply and "contaminate" (my own term) the voltage feedback circuit of the OPA1611/BUF634 tandem.

zeppu08 said:

Hi soren, what ciems will you be using on the comparison?

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The Noble K10 and the 8.A. Might even plug in my HD595 just for kicks 
 

musicheaven said:

Someone is getting some fancy stuff

I was thinking of doing the same but target the Oppo HA-1 when it'll come out, also an ESS 9018 Dac. We'll see if I am going to go there.

Let us know how this combo pans out.

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I don't plan to use the M-DAC with headphones (other than for testing purposes) but for my speakers it is absolutely sublime. Balanced XLR variable lineouts and a remote control combined with the INSANE sound quality and detail retrival makes for a very enjoyable setup with the equally brilliant active Adam speakers! That OPPO HA-1 looks like a beast tho! I wonder if the lineouts are variable? 

 
Sorry for the image quality and going a bit off-topic, but this is the Sabre rig I'm comparing the DX90 with. 
Speakers: info here and here. (The DX90 feeds them pretty damn well!)
Desktop DAC: info here and here.
If anyone is curious, the bluray playing is here. Staggering sound quality from an amazing live performance. Very, very highly recommended.
 
Plugging the mighty Noble K10 straight into the DX90 I don't feel like I'm missing anything from the speaker rig at home. Off course, listening to speakers is a different kind of experience but it's not like I feel anything is left out of the music when I'm on the portable rig. 
 
Due to a horrible accident* my PB2 is out of commision while I wait for parts. This leaves me running my CIEMs straight from the HP out instead of the topkit'ed PB2 and I'm impressed by how well the DX90 is doing on it's own. I'm missing a slight bit of soundstage and a bit of low-end weight, but that's it. 
 
*An idiot dropped the Lowepro bag with my DX90+PB2 and the PB2 input broke. The idiot was me.

borrego said:

I don't thing the DX90 can deliver +-5V PP under load. See the erji forum test results below at 32ohm/THD 1%

http://www.head-fi.org/content/type/61/id/1099901/

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That's Vrms. we are talking about Peak to Peak here. I don't think the arrow will be any far if you do similar measurements.

headwhacker said:

 

That's Vrms. we are talking about Peak to Peak here. I don't think the arrow will be any far if you do similar measurements.

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You are correct. V_rms = 0.3535 * V_pp
 
I haven't got measurement of my Arrow 4G, but I can tell the Arrow 4G can drive the PK1 at much higher volume at both the lowest and highest gain settings. It won't make much sense if the Arrow cannot even beat a 3.3V supplied BUF634 amp

So, now it's rated #116 based on 1 extremely negative review.
http://www.head-fi.org/products/ibasso-dx90-high-resolution-dual-sabre-es9018k2m-dacs-with-prostudio-coaxial-connection-kit/reviews/10952
 
No sweat, I'll order mine in the second batch anyhow

borrego said:

 
You are correct. V_rms = 0.3535 * V_pp
 
I haven't got measurement of my Arrow 4G, but I can tell the Arrow 4G can drive the PK1 at much higher volume at both the lowest and highest gain settings. It won't make much sense if the Arrow cannot even beat a 3.3V supplied BUF634 amp

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If an amp plays louder it doesn't mean it's powerful. Some amps can play at very loud volume but the signal is distorted or clipped.

DX90's Line Out voltage is 1.7Vrms (volume maxed out at least in spec sheet). Assuming the arrow can deliver it's maximum power at the quoted 11Vpp which is around 3.9Vrms. The maximum gain it can supply to it's load is 2.3X which is around around 7dB.

I'm pretty sure at high gain the arrow is clipping (19dB). But at low gain (6dB) it's just fine.

EDIT: I think the BUF634 used in the output stage is to boost current. The voltage part is handled by the OPA1611.

borrego said:

   
You are correct. V_rms = 0.3535 * V_pp
 
I haven't got measurement of my Arrow 4G, but I can tell the Arrow 4G can drive the PK1 at much higher volume at both the lowest and highest gain settings. It won't make much sense if the Arrow cannot even beat a 3.3V supplied BUF634 amp

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borrego, how does the dx90 sounds with the PK1? Does it have enough juice to bring out its full potential or does it need an amp like your Arrow? I have an OK1 and I wonder how it will synergize with the iBasso. If it cannot drive it well then I might buy an amp instead for my J3.  

This may not be a fair comparison , but I listened to all models of Astell and kern players in axpona in Chicago a couple of weeks ago . I have had the dx90 for 3 days and it has about 20 hours on it.
To me the sound of the ibasso is better than the AK models. Not to say that r not good because they are.
I have use the ibasso with my Sig Pro, phonak pfs232, AT ESW9, W3000 and it drives them all beautiful. No complains at all.
Amazing placement of instruments, layering and tonality. Bright recordings will sound like they r supposed to sound.

The DX90 certainly (to my ears) compliments the AT house sound better than the DX100 does.

jrazmar said:

   
borrego, how does the dx90 sounds with the PK1? Does it have enough juice to bring out its full potential or does it need an amp like your Arrow? I have an OK1 and I wonder how it will synergize with the iBasso. If it cannot drive it well then I might buy an amp instead for my J3. 

 

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I don't think you need to worry about juice (PK1 only needs 1mW to go at 108 dBSPL). DX90 already has plenty of that. It's what you are calling synergy which will determine if you like how it sound or not.

Reading the impressions of different people who have both daps or hdp r10, most they say dx90 is around 90% the sound quality of dx100 with better and more responsive ui but less power for hard to drive cans.So going by numbers is dx50 50%?

I wish it's that simple. How can you quantify SQ?
 
I think it's safe to say DX90 is very close to DX100 and far from DX50.

That's what i thought.Thanks

headwhacker said:

I think it's safe to say DX90 is very close to DX100 and far from DX50. :tongue_smile:

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So, ... ... ... ... DX50 ... ... ... DX90 DX100 ?

How do they think up these names?