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post #856 of 980

Morning guys, 

 

Thank you TheGrumpyOldMan for the pictures. I guess it is now safe to say this is something "official".

I will send my pictures to Yulong and I think we should all do the same. This way they would feel our "pressure" and would give us a better reply on the subject.

 

As for who asked me about who I bought it from on ebay, sorry, but I prefer not to reveal his name, as this is probably not something he is responsible for. I hope you understand.

 

In the meanwhile, can anyone else open their D18 and check? Maybe we can find a pattern here...

 

Gg

 

Quote:
Originally Posted by TheGrumpyOldMan View Post

So curiosity got the better of me, and since the D18 was about the only equipment I hadn't had a peek into, I just did:

 

 

 

I've had mine for a while, still with the green power button. I think the "official" photos may have been of a pre-production board. However it is pretty obvious that ggmesquita's board was put together by technician who was somewhat inexperienced, in a hurry, having a bad day, or a combination of those. I guess since it passed QC in terms of working, it shouldn't affect sound... they probably assumed what consumer will look inside anyway? :\

 

If you want to check yours, a tip: you only have to remove the top 2 corner screws in the front & back, the top half can then be lifted off (may require a bit of prying depending how straight the front & back plates line up) That's some solid build quality though, given how thick the plates are.

post #857 of 980

Hmm, now i'm curious how does mine look like under the hood...

post #858 of 980

It'd be interesting to know how long these changes have been shipping, and what (if any) changes it does to the sound.

 

Just throwing this out there, but could it possibly be an explanation to the debate people are having over the "warm" and "not warm" label that the D18 has?

post #859 of 980
Thread Starter 

I'll shoot an email out when I get a chance, to see if I can get to the bottom of this. Unless someone else already has? 

post #860 of 980

Because the dac is a surface mount device the board is flow soldered at the factory or at their supplier. I ran a factory with flow soldering equipment for years and from the look of that I would say it was a very sloppy job done on a machine at the wrong temperature. That shows flux from the solder all over the board which should have been cleaned at the factory. I really doubt that it came from the factory looking like that unless they are drinking while operating the equipment. I own the D18 and I would be very sorry to learn that Yulong would let that out of his factory looking like that. The heat sink glued on like that could be an attempt to solve a temperature problem with a quick fix. Not very attractive but functional. I will take the top off mine and see if it looks the same (God I hope not). Mine is a later run about five months old with the blue on/off light. I'm listening to some wonderful music now so the peek will have to wait till later.


Edited by Chodi - 3/21/13 at 10:45pm
post #861 of 980

I just noticed the transistor has no solder on the top side of the board. Even if it was a hand soldered mod it would have been done by someone who didn't know how to solder. This really does not look factory at all. Now I am really anxious to see mine, I will get to it by tomorrow. I'm betting on someone having done a very sloppy repair.


Edited by Chodi - 3/21/13 at 10:46pm
post #862 of 980

TheGrumpyOldMan's unit has the heatsink too, but it seems much more cleanly done. I'm guessing it's not a "mod" but just that the unit ggmesquita got was done poorly and slipped through QC

post #863 of 980

I will post a picture of mine tomorrow.  Curious myself.  I purchased mine Feb. 2012.  Blue light.

post #864 of 980

I just got the response from Yulong.

 
This is what I wrote:
 
"Dear Yulong, 
 
First of all, I'd like to say that I own several pieces of equipment from your company (D-100II, Tube DAC11, A18, U18 and now the D18) and I love every one of them. Congratulations for the excellent work!
 
Yesterday I got the D18 and when I was inspecting the PCB I found something that does not show on the official pictures. Please see my pictures attached.
I'd like to know exactly why was this done by you and what is the effect caused by this update.
 
The transistor gets too hot (in my opinion), reaching 70C. is this normal?
 
Thank you
Ggmesquita"
 
And this is what I got:
 
"Dear Ggmesquita
Please rest assured, it is the latest version, have a better sound.
 
best regards.
yulong"
 
Not very helpful as to find out why they did it, but at least we know it's official.
Let's wait for project86's response...
 
I would love to know exactly what difference does it make in sound.
Gg
post #865 of 980

Here is a picture of my D18.  Approx 1 year old:

 

post #866 of 980

Thanks mrcasey.

So you have the original layout, as well as signs of rework done to the IC (like mine). Regarding that, I think it's acceptable, because as far as I know, sometimes the most delicate components (like ICs) may not come out of the flow solder machine with every connection correctly soldered. Those are than manually re soldered, than back to QC.

 

Another interesting thing regarding my D18 is that although it is brand new and has this "revision / update" we are discussing, it has the green power button instead of blue. That may indicate this is not a rule when it comes to manufacture date...

post #867 of 980
Quote:
Originally Posted by ggmesquita View Post

Thanks mrcasey.

So you have the original layout, as well as signs of rework done to the IC (like mine). Regarding that, I think it's acceptable, because as far as I know, sometimes the most delicate components (like ICs) may not come out of the flow solder machine with every connection correctly soldered. Those are than manually re soldered, than back to QC.

 

Another interesting thing regarding my D18 is that although it is brand new and has this "revision / update" we are discussing, it has the green power button instead of blue. That may indicate this is not a rule when it comes to manufacture date...

 

 

 

I believe the color of the power light is a random thing (at least it was for a period of time).

 

As far as the circuit board showing signs of being reworked, or a tab bit messy, I am not concerned.  The factory changes on the board are probably on the level of a "tweak" rather than on the level of a  significant change in the sound (no doubt we will find out more about this).

 

Overall I am very satisfied with the D18.  Reliability and SQ has been top notch.  At this point I find this discovery to be more "interesting" than "disconcerting".  


Edited by mrcasey - 3/22/13 at 10:58am
post #868 of 980

FYI, I checked and mine would be ~7 months old.

 

Regarding the power LED: maybe it's the other way round? I.e. blue was used with the original, unmodified one (like mrcasey's) and the newer one (ggmesquita's and mine) has the green one? Or maybe they just grab it from a random bin at the factory tongue.gif Anyway, I'm happy with mine, the blue LEDs tend to be too bright & distracting on most of my devices (I even toned down the ones on the D18 other than the power one)

post #869 of 980
Quote:
Originally Posted by mrcasey View Post

 

 

 

I believe the color of the power light is a random thing (at least it was for a period of time).

 

As far as the circuit board showing signs of being reworked, or a tab bit messy, I am not concerned.  The factory changes on the board are probably on the level of a "tweak" rather than on the level of a  significant change in the sound (no doubt we will find out more about this).

 

Overall I am very satisfied with the D18.  Reliability and SQ has been top notch.  At this point I find this discovery to be more "interesting" than "disconcerting".  

I am also very satisfied with my D18 and it has been completely reliable. That still does not excuse the condition of the one board in the photos. Perhaps they were just having a bad day. The "mod" is the sort of thing all manufacturers do from time to time on production runs for a variety of reason. I would be pressed to believe that it was only for sonic reasons. Usually this sort of thing is more in the nature of a fix or less likely to compensate for parts availability and keep the line moving. I still love the sound of the product.

post #870 of 980

I've had the D18 for around a week and I really like the combo. I have the D18 connected to my Mjolnir and the HD800. While it isn't as good as my other dac it really isn't an earth shattering difference that doesn't really matter 99.9% of the time to me at least. It's also at a pretty good sweet spot. The D18 retails for $700 or $800 (I can't remember which) and is quite the performer. Combined with the Mjolnor and the HD800 and you have a very good sounding rig for under $3k. At a certain point in this hobby the additional gains are made by spending a significant more amount of money. While the D18 is not perfect and I find the lack of usb to be a glaring one it does a very good job of what it is supposed to do. I do find it a slightly smooth dac which I feel makes it more of an audiophile dac rather than the typical dac that tries to have no sound where everything is done on the amp side. If I had multiple amps or headphones that used the D18 as a dac there might be some mismatch but I have a separate rig for my HE6. 

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