[dfarina]

I have my dac/amp combo(Yulong D18/A18) stacked directly on top of each other,wondering if that could be a problem?For my set up it's not an easy fix to simply experiment and move things as I have it mounted in a way that requires a bit of effort.Thought I read somewhere this is a NO-NO,and would make the effort if it's worth it.Any advantage to having the dac on the bottom or top??If it's a no-no,how much separation is recommended .

 

[ProtegeManiac]

I don't really see how that is a "no-no" because we've been stacking integrated amps on CDPs since I started on Hi-Fi, unless the amp is too heavy, and while there is no chassis vibration to be dampened by weight on a DAC, it's technically the same as a CDP without a transport.
 
If anything, you should always have the amp on top, since it's the one that heats up faster. However if you put them in a shelf with no airflow then I would be more worried about that than what a reasonable weight amp would do to a DAC it has to sit on. Or, if the DAC has vents on top and the amp has vents under it, then it's possible that the sorts of noise contamination that, for example, Schiit avoids by not putting amp and DAC inside the same chassis might happen, but I have not actually heard any audible noise  when doing that.

 

[ralphp@optonline]

I have my dac/amp combo(Yulong D18/A18) stacked directly on top of each other,wondering if that could be a problem?For my set up it's not an easy fix to simply experiment and move things as I have it mounted in a way that requires a bit of effort.Thought I read somewhere this is a NO-NO,and would make the effort if it's worth it.Any advantage to having the dac on the bottom or top??If it's a no-no,how much separation is recommended .

The major concern is for the amp to have proper air flow but having looked a the Yulong web site I would say that these units both appear to be very solid and well built. I would stack them just as shown on the Yulong web site - DAC on bottom and amp on top.
 
If you are really concerned then you can always get some isolation pods/feet to place between the amp and the DAC. Check the link below for some examples:
 
http://www.needledoctor.com/New/Isolation-Feet

 

[dfarina]

Heat or weight are not a concern,I just read somewhere that the amp's power transformer can cause electrical interference with the dac and they should be positioned appart,just not sure how far apart,or if this is a bunch of non-sense???

 

[ralphp@optonline]

  Heat or weight are not a concern,I just read somewhere that the amp's power transformer can cause electrical interference with the dac and they should be positioned appart,just not sure how far apart,or if this is a bunch of non-sense???

I don't know whether or not it is nonsense but at least the manufacturer thinks it okay to stack the two units in question, as seen in this photo on their website.
 

 

[proton007]

  Heat or weight are not a concern,I just read somewhere that the amp's power transformer can cause electrical interference with the dac and they should be positioned appart,just not sure how far apart,or if this is a bunch of non-sense???

 
If the amp is well designed, the transformer will have a 'snubber' that'll remove any EMI.
 
Transformer EMI is an issue at very large currents (2A+) which is not going to happen with headphones.