Measuring and Listening Results !!!
I will limit myself here on some specific topics and MUCH MORE important, the listening results....... For more conceptual measurements, just have a look at the older DDDAC1543 pages....
For sure I will try to
answer the question (you did ask, didn't you ?) if it was all worth it, beside
all convenience and mechanical aspects ;-)
Just keep reading and see for your self !!!
To be honest, this is no rocket science..... But never the less, these images tell a short story of low noise design and how that looks like....
Just have a look at these ----->
This is the basic clock signal coming from the Tent XO clock, directly driving the I2S BUS. I was very pleased by the steep slope and almost totally flat base and top, which shows clean power supply..... Never mind the little swing up. That is basically the probe I used....
Same story for the word select signal (FS)
An example of the data line........
This is the noise spectrum of the VB+ RAIL. Normally you find a very wild spectrum here, with all kind of noisy residues of clock signals and switching noise dumped back from the logic on the power rails....
Not here, it seems the way I followed is delivering result. This power rail is very clean !!!! At least that is my opinion if you consider -110dB noise level on sub clock level and -95dB above that. A straight voltage regulator is producing more noise on its own......
Finally, no more techy stuff (although you will get a desert at the end, haha !!) and some real listening stuff, that is why we did this for, remember ??
I did 2 kind of listening tests, one with the old 8-chip DDDAC1543 version and another to listen between number of DAC Modules.....
Listening between the old version and a 12-DAC version, it can be said, that all the measures to make the design less noisy and more straight forward and directly clocked worked out. The result is a somewhat wider soundstage, clearer image and more depth.... No heartbreaking things, but as we improve everything it is nice to have some sound gain as well !!! And that we clearly have. Time to put the old DDDAC in the shredder ? OF COURSE NOT !! The difference between the old DDDAC1543 and a integrated CD Player solution is much bigger than between version 1 and 2......
Now for the story of adding more DACs, well that is of a different kind.... When going from 12 to 24 DACs a clear gain is found in low level detail and dynamics. Drive is much better and interestingly enough (I do not understand why.... :-) the bass gets tighter !! In general the whole sound gets much more bite and stage..... I liked this very much and the extra cost to do so is not so bad....
Going from 24 to 60 DACs shows improvement from the same sort, but with more focus on sound stage and air in between voices and instruments. The improvement is clearly audible, but more of a good tweaking kind..... But as it always is, if you hear it, you don't want to go back :-))) And that tells something eh?
All relatively normal improvement so what about the USB Interface ??? Well, now we are talking a completely different story !!!!! ------------------>
The sound of a bit copied CD sound unbelievable "clean". The soundstage goes much deeper and wider, you can really "look through" the whole sound stage. For example, listening to a choir, I could identify individual line up where with SPDIF this was diffuse..... Dynamics and tonal balance do not change, it is really the extreme transparency of the stereo image.....
This is so good, I already bought a fan less PC, a 8" touch screen and a USB disk drive. This will turn in the coming time into my Music Server !!!! (I will report when it is ready :-)
Oh, not to forget, by comparing the Tent Clock and the normal Crystal, The Tent clock brings more defined focus..... When the gain from SPDIF to USB is 100% on some kind of imaginary scale, than this gain would be on roughly 3/4 of that scale...... So you already guessed: YES, the TENT CLOCK STAYS !!!!
I have not did a great deal of testing with all kind of cables (I use a Monster cable for USB2.0 use and was pretty content with it) and PC tweaking settings (like buffer size etc).. At glance I could not tell big differences...... So I leave this up to any one who built one and please let me know, I learn as well ....
Some last comment may be, and also a very interesting one...... I compared just for fun, a song directly from the hard disk and from the CD-ROM drive (with the CD in it of course) and there was no major difference on the descriptions above, BUT ( !!! ) you could absolutely tell unclearities and kind of small distortions in long tones compared to the hard disk..... It seems that this was actually an observation of the error correcting from the drive !!! When switched back to the hard disk, these little effect disappeared immediately..... interesting eh??
Almost forgot..... How does the built in DAC sound ?? Well, to make this short and bring this behind us, sounds like a cheap CD Player......... as monitor ok, as interesting test ok, but I will not be tempted to listen to this............. As stand alone external sound card solution, we talk differently. The world is relative, haha !! In that case you probably do not want to go back to your built in sound card anymore and use this option.......
Proper USB Audio
The only way to make this a successful addition is to configure your PC with care.......
First of all, you need to make sure your PC is absolutely set up correctly.... a few tips:
Disable the volume control in your player (I use Foobar, as it is easy to configure things like this)
Use bit for bit ripping (like from Audio Exact Copy)
Remove all sound effects, DSP's etc etc from the player settings
Make sure to select some kind of "direct" output in your player and to select the "USB Audio DAC"
If appropriate, disable all RESAMPLING settings. make sure everything is straight 16 bit 44.1 kHz !!!
Below I share a few screenshots of my configuration..... (sorry for the German, grinsssss)
connection the DAC, windows is installing standard drivers and when you look
into the sound properties, you will get the screen
If you have disabled the volume and picked a direct driver, you can slide the control, but the sound stays the same. Good !!
This is an example how my Foobar looks like.... Please note I selected the USB device and used "DirectSound v2.0"
The DSP Manager is set so, that NO plug-in is installed !!!! so the left screen is empty then...
These 3 are not 100% necessary,
but might be interesting for more experienced users, as it totally disables
all Windows drivers in the sound process.....
It means there are also no WAVE sounds any more !! All internal Sound drivers are inactivated.... Only the WAV files and the USB DAC are in play now.... so can be unpractical when the PC is also used for other applications :-(
WARNING: In this set up, the built in DAC from the PCM2707 will NOT work ....... Which I found very interesting, but have no explanation for .....
Basically the WAV File is sent by the player directly to the USB output now. Sounds minimalistic.... doesn't' it ????
TRY FOR YOURSELF I would suggest, play around as much as you like and let me know what your favorite settings are !!!!!!!
NOTE: Having your PC or Notebook in the Livingroom and in the Audiorack, is not an optimal solution of course. Therefore I have set up a special (very small) Audio Streaming Server. Read all about it in the "Other Projects" capital "Item 9"
It took me a long time to come up with this revision and it was all worth while, specially the USB receiver is a great improvement. I never had thought, that in my high end audio, one day a PC would make its entree..... I like to thank as well all the inputs I received from DIY. Without those, there never would have been a MK2 I think..... Again, the internet has proven to be a great tool to help our community to share ideas and designs and experience and at the end of the day we have reached the next step in great audio pleasure !!!!!!
If you are interested to built a DDDAC 1543 MK2 system for your own, see my sales page and the KIT Story.....
Happy Listening and Building !!!!
IMPORTANT: The information provided on this page is intended as guide for DIY activities and therefore free to copy and or publish. If any one wishes to use any of the information from my WEB site, please make sure to refer and footnote to my URL Link as source! Doede Douma