[Vicca Tito]

Well friends,
after some longer period of time needed for CE certification problem to be solved for EU import (what actually cost me over 100 euros), I've finally got my DAC/amp which I've just started to warm up, and for the first impression is doing fine so far, meaning that will end up kind of higher on a scale by some time. It makes me happy.
But one tricky thing bothers me a little.
imf, During the work the mode shifting occurs spontaneously sometimes (for example, from optical to PCM input, or the other way around), which could be a little annoying.
Any clues to that?
Otherwise the machine is OK and well sounded.

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[size=xx-small]PC--SB3-optical cable--yulong DAC/DAH1 Mark--Sennheiser HD595[/size]

 

[Pricklely Peete]

Are all inputs being used or just one. I know for a fact the computer will send a signal continuously asking for a lock with the DAC receiver chip even though nothing may be playing on that input. The only solution is to pick a type of input and use that exclusively or if there is a buried menu selection in the DAC, disable auto select. It may not be possible though.


It also might be an indicator of a bad cable.....worth checking out...


How are you using the unit, may I ask ? List your gear and connections please

Peete.

 

[Bigjppop]

I've never had that problem with my Yulong but I've only run one input at a time (so far only USB).

One thing I do find a little maddening about the Yulong is that when you do a hard shut down (power switch on the back) and start again it goes back to its default input and volume setting (zero volume). Oh well, what can do!

 

[Vicca Tito]

Quote:

Originally Posted by Pricklely Peete /img/forum/go_quote.gif Are all inputs being used or just one. I know for a fact the computer will send a signal continuously asking for a lock with the DAC receiver chip even though nothing may be playing on that input. The only solution is to pick a type of input and use that exclusively or if there is a buried menu selection in the DAC, disable auto select. It may not be possible though. It also might be an indicator of a bad cable.....worth checking out... How are you using the unit, may I ask ? List your gear and connections please Peete.

Wellll,
In the matter of fact all connections are attached to its inputs and outputs.
the gear is quoted there:
I will do it again, more precisely:
FLAC --> Squeezebox 3 --> Sony optical cable --> Yulong DAC --> Sennheiser HD959
The other two: Densen Beat 100 amp (tapeout) --> Silver cable DIY--> Yulong DAC --> Sennheiser HD959 and
Sony CD-940QS --> Coaxial cable --> Yulong DAC -->Sennheiser HD959
and as a DAC: Sony CD-940QS --> Coaxial cable --> Yulong DAC --> Densen Beat 100 amp --> JBL Ti 1000 speakers

Hm.. How the one is selected I don't know, actually this only can be selected by pressing mode button.
When I press it to a one source (i.e. optical input) it could spontaneously switch to i.e. PCM in (what actually happens not so often).
Also, when input is paused the yulong automatically turns MUTE mode... and returns back automatically from it when input starts playing again. I don't know weather this happens always in Yulongs?

 

[Pricklely Peete]

It seems to me the auto lock is hunting among active inputs for a signal lock at times (if all inputs are powered up, meaning The Densen and Sony CDP and Squeezebox).

I need to study the Yulong a little more closely. The mute function, when signal is paused, is typical for a lot of DAC's and CDP's of late.

If it's simply a manual mode switch it should not be hunting around for another input and switching randomly. Could that be a software glitch or a faulty control chip ? Tough to say for sure....have you emailed the Vendor you bought it from for some support ?

I'll have a look sometime today at the Yulong specs to see if I can come up with something for you. In the meantime unhook 2 of the 3 input sources to it and run the unit to see if it hunts around with only one input active. That should sort out whether or not it's maintaining lock. Make sure you use a known good cable to rule out any other factors. I'm not saying your cables are bad, just saying be sure of all other factors.

Peete.

 

[Vicca Tito]

Thank you so much.
Any info about that would mean great help for me.

For example, today it seems that this switch didn't happen.
Maybe it's only warming up, I don't know forsure.

 

[Vicca Tito]

No, in the meantime it begun to switch again.
Now, more frequently, it switches to PCM-in from optical out. Any thoughts? Will try another optical cable and the coaxial one.
It's really starting to annoying me.
Would report on this.

Happy about every comment...
Any communication with vendor would not be a solution, since it is at the only start compromised by a CE problem in Europe (European certification of product safety), and would bring new payments and taxes (also the import problems).

 

[Pricklely Peete]

Quote:

Originally Posted by Vicca Tito /img/forum/go_quote.gif No, in the meantime it begun to switch again. Now, more frequently, it switches to PCM-in from optical out. Any thoughts? Will try another optical cable and the coaxial one. It's really starting to annoying me. Would report on this. Happy about every comment... Any communication with vendor would not be a solution, since it is at the only start compromised by a CE problem in Europe (European certification of product safety), and would bring new payments and taxes (also the import problems).

Surely the exchange of info (to the vendor) via email isn't subject to taxation is it ? That is what I mean by support.

I still haven't had time to look at the Yulong in depth, but rest assured I will.

Peete.

 

[ILikeHeadphones]

People have said that the Yulong loses its mode and volume settings when turned off. When powering up the mode must be selected again. (Also the volume needs to be turned up again). What if there is some kind of power interruption and the Yulong is resetting itself?

Here's a test. I'm curious what the order of the mode cycling is. And when you turn it off manually and turn it back on, does it reset to PCM (I assume this means analog). If the unit resets itself to PCM then that would suggest the switching problem you are having could be a power issue. Is this on a surge suppressor or UPS of any kind?

The only other thing I can think of is maybe there's an infrared signal hitting the Yulong? I understand there is a remote control so maybe its getting a remote "change mode" signal somehow.

I've been looking at getting this amp for a while now. One big thing is the use of the multiple inputs. If that doesn't work like it's supposed to, it would be a deal breaker...

Can anyone else please confirm that multiple simultaneous inputs works on their Yulong DAH1? Obviously, it should not be switching modes randomly.

Unfortunately, even the best hardware sometimes has problems slip through in manufacturing. You may need to get a replacement if the problem can't be solved.

Good luck.

 

[Vicca Tito]

Quote:

Originally Posted by ILikeHeadphones /img/forum/go_quote.gif Here's a test. I'm curious what the order of the mode cycling is. And when you turn it off manually and turn it back on, does it reset to PCM (I assume this means analog). If the unit resets itself to PCM then that would suggest the switching problem you are having could be a power issue. Is this on a surge suppressor or UPS of any kind? The only other thing I can think of is maybe there's an infrared signal hitting the Yulong? I understand there is a remote control so maybe its getting a remote "change mode" signal somehow. I've been looking at getting this amp for a while now. One big thing is the use of the multiple inputs. If that doesn't work like it's supposed to, it would be a deal breaker... Can anyone else please confirm that multiple simultaneous inputs works on their Yulong DAH1? Obviously, it should not be switching modes randomly. Unfortunately, even the best hardware sometimes has problems slip through in manufacturing. You may need to get a replacement if the problem can't be solved. Good luck.

The default startup mode is Coaxial.
It, eventually turns randomly to PCM (put not always, sometimes, supprisingly it switches to USB).
I would test it a little bit more.

 

[Vicca Tito]

And I have tried some tests...
Yulong DAC has being turned on 24 hours without any input running.
When started it turned itself to Coaxial line input by default, and wasn't switching between modes at all for 24h.
So, by far, at least for me, it seems that nothing in the DAC itself has turning
these switches on. Maybe its the faulty optical cable, I don't know...
I am going to play it by coaxial input from now on, change the optical cable
And the report will follow...

 

[Pricklely Peete]

Quote:

Originally Posted by Vicca Tito /img/forum/go_quote.gif And I have tried some tests... Yulong DAC has being turned on 24 hours without any input running. When started it turned itself to Coaxial line input by default, and wasn't switching between modes at all for 24h. So, by far, at least for me, it seems that nothing in the DAC itself has turning these switches on. Maybe its the faulty optical cable, I don't know... I am going to play it by coaxial input from now on, change the optical cable And the report will follow...

It's possible the TOSlink has had the biscuit so to speak or the lenses are scratched/dirty causing refraction of the light pulse ?....just a guess at this point.

I looked at the material (data sheet specs/descriptions etc) available for the Yulong, sorry it took me so long. There doesn't seem to be a auto lock feature, but it isn't denied either....basically the info I dug up was pretty vague from at least a half dozen different sources.

Peete.

 

[Vicca Tito]

Big thanks Pricklely Peete

Actually, it has being running out for at least 5h so far without any of affordmentioned switches. Thought the much of it is likely to be accounted on a bad optilink cable or whatever and wherever the faulty optical glitch was.
Coaxial is running OK. I am listening the DAC out mode from SB3 (via Audioquest vsd2) and Van den Hul i.c.cable to Densen B100 and it sounds rather lovely at first sight, but more transparent and dry as I would prefer (I'll explain it later).
No switches anymore.

 

[Vicca Tito]

Now, there it is.
A brief overview of how it sounds.
By far, it has been running at least 120 hours, (manufacturer recommends 200 h of burn-in).
Apart from this the mute mode is has being continued to switch on spontaneously from time to time, but not so very often, so I will not consider it as a fault. I am a man of good will

This combination is tested: FS AmiloPro PC with WD external 500GB storage - Logitech Squeezebox 3 --[size=xx-small]Audioquest VSD2[/size]-- Yulong DAC/DAH -- Senn HD959 (as a headamp) or all the same but with added [size=xx-small]VdH D102MKIV[/size] -- Densen Beat B-100 --[size=x-small]Audioquest type 8 Hyperlitz[/size] -- JBL Ti1000 (as a DAC). Comparation was done (for DAC testing) using the same combination, but with Cambridge audio DACMAGIC-3 instead of a Yulong.

1. Yulong as a Headamp (comparative to regulated phone output of AKAI amp AM-2400, relatively good one):
Well, pretty decent one, in terms of details and transparency of reproduction.
It demands good recordings. The bass area is reproduced adequately, being very ear-palpable and with good-definition. Some tracks with loads of lower registers and doubled bass seems to be less well defined (Madonna - Music, Diana Krall - I am an errant girl...), but it is obviously the matter of headphones, rather than amping. I do not have any obstacles with mids and heights, everything is there and spaceously presented. Somehow I didn't expect the miracle in instrument positioning, but that one, at least for me has failed. The whole music picture you get is just a bit flat and boring, but rather good for price range. If there is a scale cold (0) to warm (10), let's put it simple: our DAC would be at 4 degree. By my tastes that's well out of what I expected, I did hope that it will score at least 6-7. I am a good old valve-amp -kind of guy, and maybe that's the reason. But warmth is not the feature of Yulong DAC. However, it's the headamp testing and rather superficial one, so please consider eventual changes in performance, since the unit is received 2 weeks ago. The obvious quality of DAC as an h.amp is linearity, naturalness and transparency, as well as a plenty of well administered details from coaxial source input. Optical input is similar I didn't noticed that much difference. I have enjoyed many tracks (Sting - Fragilidad(Portugese), Tina Turner - Private dancer, many Jaz vocalists setups and for example Jane Monheit or Madelaine Peureaux or Sara K and many others...) especially in colourfull and rich sound where I haven't noticed lack of warmth, what seems to be a kind of negative side of our DAC. The other one is by far, more noticeable, and that is the lack of liveliness and vibrancy of more dynamic tracks (The Smiths - These things take time, many other tracks, Jerry Douglas - the most of his bluegrass tracks, Spandau Ballet - Communication, etc).
This was just a start. The next of review of this fine little DAC will follow...

Have a nice Phonegig

 

[Vicca Tito]

And I would also add some technical points observed by majority:
- Display is too dark, and as the others I will probably take that piece of glass down soon
- I didn't noticed any problems with (rather funny looking) remote. It's working fine
- The problem with volume setup is staying there, but since the remote is good I don't mind at all
- Mode switching is also there, maybe this unit simply has this fault, maye it's something else, I will see.

Next days I would change Audioquest cable for Ixos and test it with two other amplifications (as a DAC - Densen B100 and handmade Valve-amp with 2x2 EL-34 tube output).