Review: Yulong D100 DAC/amp - reference quality with a reasonable price
Jan 30, 2013 at 3:33 AM Post #1,111 of 1,182
Quote:
Hi,
 
Lemme see if I got after reading a lot: I need an amp if I want to use this one or the Yulong's sibling with speakers, do I?
 
Please, if you don't mind, answer the following questions. What's the difference between a combo dac/amp and a receiver? Is there any hifi dac/amp in this level all in one? What is the buffer?
 
Thanks for helping me.

Heres the thing:
 
Normal Receivers have (for Audio 8channels) all in one:
Processors -> DAC -> Preamp -> Power amp
 
HiFi systems are Stereo and have all this seperately:
Transport (CD Player, Music streamer)
DAC (Converts to analogue and line level)
Preamp (Takes line level input and boosts it, but still not enough for passive speakers)
Power Amps (even Mono Blocks, 1 per channel, just has a power button, takes the input from the Preamp and boosts it a fixed amount)
 
so as you can see, a lot more specialised, but a hell of a lot better
Quote:
All receivers, except for 2 channel stereo only units, have built in DACs for all 5 or 7 channels (depending on if they are a 5.1 or 7.1 model). In some cases they have very nice DACs - a high end Anthem, Marantz, or Pioneer Elite may be just as good as an entry level or midrange DAC. I'd say the D100 is better than most surround receivers but certainly not all of them - some receivers cost thousands of dollars and are very nice. Still, they pack a lot of features into one box and something has to give, even at $2K or so. 

^^ this
 
I can think of a few 8channel receivers that cost frightening amounts of money. 
 
Feb 21, 2013 at 9:23 AM Post #1,112 of 1,182
I understand from your review that the DAC in the D100 and in the DAC1 are very very similar, but how do they compare in the headphone amp section?, the goal being to have an analytical sound for mixing and mastering
sorry for my english
 
and the matrix quattro dac as well...
 
Mar 14, 2013 at 8:14 PM Post #1,113 of 1,182
Does anyone know what the output voltage is on the d100? i don't see it published anywhere. Instead only the headphone power figures are provided. In particular I am interested in output voltage for both RCA and XLR.
 
Mar 14, 2013 at 8:49 PM Post #1,114 of 1,182
Quote:
Does anyone know what the output voltage is on the d100? i don't see it published anywhere. Instead only the headphone power figures are provided. In particular I am interested in output voltage for both RCA and XLR.

 
I believe it is the typical 2V RCA and 4V XLR. Or else something very close to that. 
 
Mar 24, 2013 at 6:09 AM Post #1,115 of 1,182
I'm planning to mod D100 mk1. Get rid of the integrated amp (maybe cut out that area of PCB completely) and put in, for example, O2 amp + digital pot like AD5290. I would reprogram the already present MCU to controll that pot from some kind of rotary encoder in place of that analog pot. Main reason for wanting a digital pot is great channel balance, because I listen at relatively low levels. Also, the "sound" button would be used to set gain of O2 (high=~12/low=1). The LCD would display volume bar (instead of that useless line YULONG Audio DAC), maybe gain setting (high/low) and of course the sampling rate + input. These are just some ideas. I haven't checked whether they're electrically or physically possible yet. :cool:





Ooh, another idea. Use Sound+Input button combo to change O2 input via additional relay: Input1=D100; Input2=rear RCAs
 
Mar 24, 2013 at 4:32 PM Post #1,118 of 1,182
This hobby makes me wish I studied ee when I was in school. I wish I had the ability for such things
 
Mar 24, 2013 at 6:19 PM Post #1,119 of 1,182
That's quite an ambitious project. I assume you have the capabilities to handle all this? Most people aren't equipped to do that sort of thing.
I've been messing with microcontrollers for a while so that could be a fun little project. MCU/software part is quite easy, I'm probing my unit at the moment. :redface:

What I've gathered so far:
  • The controller is 89C54RD+.
  • I2S LRCLK (AD1896's pin 6) is connected to MCU pin 11, that's how it determines the sample rate.
  • MCU Pin 1 via S9012 transistor controls I²S feed into AD1896 (two green DPDT relays): logical 1=CS8416; logical 0=TAS1020B.



I would also read up a little more on the O2.  Using a gain of 12 with a full output signal from the dac section is going to cause major clipping.
Thanks for the remark!

Also I'm not sure whether O2 is better than integrated. Has anyone compared O2 vs D100 integrated AMP?
 
Mar 24, 2013 at 7:42 PM Post #1,121 of 1,182
More findings:

  • MCU pin 2 is connected to CS8416's RXSEL0.
  • MCU pin 3 is connected to CS8416's RXSEL1.

So, when MCU pin 1 is high (which means CS8416 is connected to AD1896's I2S input), RXSEL[1:0] are used to select which pin, RXP[3:0], is used for the receiver input:

  • RXSEL1=0; RXSEL0=1 — optical
  • RXSEL1=1; RXSEL0=0 — AES
  • RXSEL1=1; RXSEL0=1 — coaxial

This information is for others that might also consider to mod this dac...:wink:
 
May 18, 2013 at 7:16 PM Post #1,122 of 1,182
Hello Head-Fi! Still new hear but the heaps and heaps of reading has kept me busy. Even managed to pick up a few gear in the process.
wink.gif

 
I just picked up a used Yulong D100 in mint physical condition and thought I'd ask the more knowledgeable if this one niggle should be something of a concern. Basically the sample rate portion of the LED display flickers steadily, with or without music running on both USB and Toslink feed. When the source (my laptop with both Toslink and USB) is turned off, the "No Sample" does not flicker. Also, Toslink won't run at 192KHz, just static noise on one channel. Same source and cable works fine on the Mini-i at 192KHz. Other than those two, everything seems to be of working order. Should this be a concern or should I check anything else?

Edit: Just watched the vid, the phone camera doesn't capture it well but it is flickering from the very beginning. Shifting the angle makes allowed the camera to capture it. Also the flicker is steady despite it looking erratic.

 
May 18, 2013 at 8:00 PM Post #1,123 of 1,182
Not sure what the deal is with the flicker, but it's common for toslink to top out at 96khz. I don't know the exact science behind it, but it has something to do with the quality of the signal that is being sent/received and the fact that toslink isn't really a good interface to begin with.
 
May 18, 2013 at 8:14 PM Post #1,124 of 1,182
I believe the flickering was something that happened with early models. It was said to be by design, indicating signal lock. Which is why it doesnt happen all the time. Or something like that. But customers complained that it looked odd, so Yulong did away with it. I'd guess you have a lower serial number unit. Right? I could be remembering wrong, and it was just a minor glitch that later got fixed. But I know it didn't affect anything else - just looked funny to some people.

As for Toslink, most units I've tried which claim to accept 192khz actually top out at 96khz. In fact, most transport are the limiting factor rather than the DAC. It's just not a very robust interface.
 
May 19, 2013 at 4:39 AM Post #1,125 of 1,182
The sample rate is determined from I2S word clock by the same MCU that controls the LCD. So flickering may not necessarily indicate anything bad with the DAC subsystem, it could simply be poor frequency counter implementation. That's even more plausible if you say sound is fine.

I also couldn't get 192 through optical. Only static. My serial is 0384
 

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