[miyinan]

very nice short interconnects
 
Quote:

 

[sling5s]

 
For those who can't decide between Nuforce and HDP.
I have a definite answer to this:  Yulong D100 is clearly better. 
The HDP in comparison was narrow in soundstage, lean in bass and bright in it's presentation.
The Yulong as an amp has clearly wider soundstage with more bass and bass impact and yes, it's neutral.
As for the Dac, it's neutral and resolving. It's smoother but more resolving than the HDP. And more important, the Yulong has way more power.  
I'm glad with the purchase.  It's an improvement over the HDP in every way.
 
Thank you Jeffery/Tam Audio/Coolfungadget & project 86.

 

[roachbro]

I agree the Yulong is better than the HDP right out of the box. The HDP is more analytical and a lot harder on my ears. With the  Yulong I can listen for hours on end. I have the HDP at work and the Yulong at home. That said, the Yulong is new so I'll have to listen to it a bit more.

 

[rymd]

oho
thanks for those comparisons guys. I'm glad I went with the yulong in the end (but the nuforce still has the size advantage).
 
sling5s - do you own a hdp or did you just briefly listen to one?
 

 

[sling5s]

I had it for almost a month and returned it.  

 

[kite7]

I believe what you've been hearing on the HDP are attributes of its headphone amplifier, not so much the DAC. HDP's amp is fairly clear and crisp sounding that is void of any artificial smoothing  that some people crave and combined with a condensed soundstage, it can be more fatiguing.
 
Quote:

I agree the Yulong is better than the HDP right out of the box. The HDP is more analytical and a lot harder on my ears. With the  Yulong I can listen for hours on end. I have the HDP at work and the Yulong at home. That said, the Yulong is new so I'll have to listen to it a bit more.

 

[roachbro]

 
Quote:

I believe what you've been hearing on the HDP are attributes of its headphone amplifier, not so much the DAC. HDP's amp is fairly clear and crisp sounding that is void of any artificial smoothing  that some people crave and combined with a condensed soundstage, it can be more fatiguing.
 

 

Makes me wonder if I should just sell my HDP or keep it as a dac and pair it with a nicer amp. It sucks because after listening to both I feel a lot more comfortable with the Yulong.  I need a good portable amp for my commute so maybe I'll get a stepdance or L3 when it comes out.

 

[sling5s]

I found the Dac on the HDP to be on the bright side also (not just the amp) much like the Benchmark Dac 1.  It's slight might you, but still on the bright side of neutral. But the Dac is good but not neutral enough for me. 
So if you want a more neutral dac, than you might want to sell and get something else.
It's what makes the HDP so bright, the dac is on the slight bright side coupled with the amp which is more so on the bright side.
 
But if you have warm headphones and you want to brighten them up and tighten up the bass, like the hd650/hd600, it's a great combo.
 

 

[kkl10]

 
Does somebody know what are the output impedance values of the Yulong D100 headphone jacks?
Where can I get that information?
 
Thanks!

 

[etalon90]

Got mine yesterday.
I analysed the circuit and can say that the output impedance is very low.
 
When you leave the DAC section, you pass a signal cap (wima), go thru a potentiometer and reach an op amp that feed a push pull emitter follower. Transistor stage are included in feedback loop. So the op-amp control everything.
 
In closed loop, the opa2134 datasheet state about 0.01ohm. with the wire+ connector resistance, maybe 0.4ohms.
 
 
the low impedance output is just a serial resistor of 47ohms that feed the 2nd headphone jack. If you want to loose dynamic, that is the output to use...
 
 
 
As for the class A, it's a real joke.
the output stage have a iddle current of about 11mA.
On my 45 ohms orthodynamic (he-6. the 45 ohms is measured with my Fluke DMM)
it mean that I can reach 1volt peak-to-peak in pure classA
translate in 0.34V rms
do the math and  the result is a whooping 3.8mW of class A before going to class AB
 
I want to raise the bias voltage but the transistors are surface mount and no heatsink are present. the transistor will blow if I crank the current. they are stated at 300mW maximum dissipation. (they are already at about 165mW, so not more room)
 
A dedicated amp is the solution for me unless I throw my warranty away and modify the output stage. (might happen).
For now,I use a modified 35Watts vintage stereo receiver. I  bypassed all the control section (bass, trebble, balance, bass boost) and increased idle current. That 20 years amplifier can now feed 700mW of pure classA before switching to class AB. It kick the Sh**T out of the D100.
Look at classified, get a vintage SS amp, modify it and use the D100 as a DAC.
 
MArtin

 

[kkl10]

Thank you for your answer!
Interesting findings...
 
Sorry but I'm not sure if I understood what is the output in the high impedance headphone jack? (I'm still learning about this matters... forgive my ignorance or lack of literature smart...)
Is it 0ohms? Is that what you mean?
What did you mean by "loose dynamic"? And on what jack?
 
Thanks!

 

[kkl10]

 
By the way etalon90, are you able to find out about the voltage swing on both jacks?
Or have you said that already? :/
Forgive my ignorance...
 
Thanks!

 

[sling5s]

I don't get all the terminology. 
Are you saying that this is a poor amp for high impedance headphones but alright for low impedance headphones.
Also that the "low" headphone jack is more dynamic than the "high" headphone jack?

 
Quote:

Got mine yesterday.
I analysed the circuit and can say that the output impedance is very low.
 
When you leave the DAC section, you pass a signal cap (wima), go thru a potentiometer and reach an op amp that feed a push pull emitter follower. Transistor stage are included in feedback loop. So the op-amp control everything.
 
In closed loop, the opa2134 datasheet state about 0.01ohm. with the wire+ connector resistance, maybe 0.4ohms.
 
 
the low impedance output is just a serial resistor of 47ohms that feed the 2nd headphone jack. If you want to loose dynamic, that is the output to use...
 
 
 
As for the class A, it's a real joke.
the output stage have a iddle current of about 11mA.
On my 45 ohms orthodynamic (he-6. the 45 ohms is measured with my Fluke DMM)
it mean that I can reach 1volt peak-to-peak in pure classA
translate in 0.34V rms
do the math and  the result is a whooping 3.8mW of class A before going to class AB
 
I want to raise the bias voltage but the transistors are surface mount and no heatsink are present. the transistor will blow if I crank the current. they are stated at 300mW maximum dissipation. (they are already at about 165mW, so not more room)
 
A dedicated amp is the solution for me unless I throw my warranty away and modify the output stage. (might happen).
For now,I use a modified 35Watts vintage stereo receiver. I  bypassed all the control section (bass, trebble, balance, bass boost) and increased idle current. That 20 years amplifier can now feed 700mW of pure classA before switching to class AB. It kick the Sh**T out of the D100.
Look at classified, get a vintage SS amp, modify it and use the D100 as a DAC.
 
MArtin

 

[eimis]

Quote:

Also that the "low" headphone jack is more dynamic than the "high" headphone jack?

 

I think he means vice versa.

 

[sling5s]

Having had the D100 for awhile, I find the Dac to be exceptional.  But the amp has certain weaknesses to me: bass seems a little loose and the midrange thin and grainy.  I feel like that's the thing to ask/say but will burn in help?