YULONG DA1: Flagship All-in-One with AK4499, 5W Class A BAL headphones and Pre-Amp
Jul 12, 2021 at 3:31 PM Post #31 of 49

project86

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DSCF1608.JPG


One more, just because. This thing is a beauty.
 
Jul 15, 2021 at 1:11 AM Post #33 of 49

classicjazz

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I just received my DA1 (just the main unit, no external power supply). I am running Roon and the DA1 is connected via coax to my Auralic streamer.

I've noticed that the chassis is quite warm, measuring 44º C in many places. The ambient temperature is 24ºC. The unit is on the first shelf and has 4 inches of air space above it and lots of space around. Is this temperature the normal working temperature? It seems hot, especially for a DAC/preamp/headphone amp.

Does anyone have any insight?
 
Jul 15, 2021 at 1:32 AM Post #34 of 49

vkenz

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I just received my DA1 (just the main unit, no external power supply). I am running Roon and the DA1 is connected via coax to my Auralic streamer.

I've noticed that the chassis is quite warm, measuring 44º C in many places. The ambient temperature is 24ºC. The unit is on the first shelf and has 4 inches of air space above it and lots of space around. Is this temperature the normal working temperature? It seems hot, especially for a DAC/preamp/headphone amp.

Does anyone have any insight?
It must be those mosfets that are using the chassis as heatsink. Look at page 1.
 
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Jul 15, 2021 at 3:09 AM Post #35 of 49
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I just received my DA1 (just the main unit, no external power supply). I am running Roon and the DA1 is connected via coax to my Auralic streamer.

I've noticed that the chassis is quite warm, measuring 44º C in many places. The ambient temperature is 24ºC. The unit is on the first shelf and has 4 inches of air space above it and lots of space around. Is this temperature the normal working temperature? It seems hot, especially for a DAC/preamp/headphone amp.

Does anyone have any insight?

Full Balanced Class A, this is not unusual. In fact, I have stated HERE that
"The output stage is composed of 12 high output audio grade power transistors. These BJTs (Bipolar Junction Transistors) are really powerful and sing like a nightingale, they deliver up to 5 watts per channel output (at 32ohm loading) with stellar dynamic range in DA1. However, they are extremely hot when operates in Class-A, we have tried numerous methods to cool them down and our final option is to mount them horizontally so that the power transistors can use the CNC machines aluminium chassis as heat sink to cool down itself effectively."
 
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Jul 15, 2021 at 4:58 AM Post #36 of 49

classicjazz

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Thank you for the follow up. I had read that information and knew the unit was biased into Class A. I guess I am used to larger chassis that can dissipate the heat over a larger area. I just wanted to confirm that the temperature is as expected.

If I were to get the power supply, do you recommend keeping them on separate shelves to minimize heat build up? Many of the photos show the units stacked.
 
Jul 15, 2021 at 5:22 AM Post #37 of 49
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Thank you for the follow up. I had read that information and knew the unit was biased into Class A. I guess I am used to larger chassis that can dissipate the heat over a larger area. I just wanted to confirm that the temperature is as expected.

If I were to get the power supply, do you recommend keeping them on separate shelves to minimize heat build up? Many of the photos show the units stacked.
Yes, definitely. :beerchug:

Under the heading of "Connecting to DA1 Power Station" in the user guide, I have written:
The DA1 Power Station can be placed below the DA1 Main Unit when setup as a stack. Please do not put the DA1 Power Station on top of the DA1 Main Unit, this will affect the audio performance. Placing the two chassis side by side or into different shelf of a proper HiFi rack will be more desirable.
 
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Jul 15, 2021 at 1:01 PM Post #38 of 49

project86

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I've noticed the DA1 does get fairly warm, but nothing beyond what I've experienced from various other gear. My KGSSHV electrostatic amp gets quite a bit warmer, as did a lot of the Schiit gear that has come through my system. So I wouldn't worry about it.

One little detail I find thoughtful is the fact that Yulong provides two umbilical cables to connect the main DA1 to the power station. One is fairly short, useful for stacking (DAC on top, as mentioned) without leaving a big mess of extra cable everywhere. The other is long enough to separate by a good distance, in case you wanted to throw the power station at the bottom of your audio rack or something. It's a small touch that shows someone really thought things through on this device.
 
Jul 15, 2021 at 2:31 PM Post #39 of 49

EagleWings

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Hi John, does the tone of the DA1 err towards the warm/full side of neutral or towards the other side?
 
Jul 16, 2021 at 4:43 PM Post #40 of 49

project86

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Preliminary thoughts only... it seems fairly neutral with just a hint of warmth. So not all that different than DA10 in terms of tonal balance. It also has some of that same midrange emotion that I loved about the DA10. So not boring neutral in the least.

It's tricky though, because when I play something with bombastic lows, the DA1 has such authority that it makes me think of a really warm sound. But then when I focus on sparkly highs and open, airy presentation, it does that so well that I automatically start thinking it's a lightweight, bright sounding device. In reality neither of those is true, but it's just such a good DAC that it shifts my focus at times.

This also happens using my Niimbus US4+ paired with my Resonessence Labs Mirus Pro Signature DAC (total cost over 3x the DA1 with power station), which is a sign that Yulong did something really well here.
 
Jul 17, 2021 at 12:35 PM Post #41 of 49

project86

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Minor update, I just picked up the proper cable to connect a USB C source to the DA1, and I've had great results. My various LG V-series and G-series phones work flawlessly using Hiby Player as well as USB Audio Player Pro. That includes 24/192 and DSD material with both apps. I intend to try a few more devices as it really would be best to use a tablet in that scenario, a phone just feels small. That said, the SQ is superb thanks to Yulong's JIC processing.

On the down side, my daily driver Pixel 4 XL does not work. UAPP isn't even available on the Play store (and I don't want to mess with trying an APK install). Hiby Player looks like it will work, but then stalls for a moment before forcing a reboot of the phone. So obviously the phone doesn't play nicely with USB audio output. That's obviously a Pixel problem, not Yulong's fault.
 
Jul 17, 2021 at 8:34 PM Post #42 of 49

Nick63

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poject86,

Yulong's description of the DA1 says it has a "high-power tube Class A amplification circuitry". Could you explain this? It does not use tubes it seems. I am not sure I want any tube sound added as I have always used solid state. I would appreciate any thing you could tell me about this.
 
Jul 17, 2021 at 10:00 PM Post #43 of 49
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poject86,

Yulong's description of the DA1 says it has a "high-power tube Class A amplification circuitry". Could you explain this? It does not use tubes it seems. I am not sure I want any tube sound added as I have always used solid state. I would appreciate any thing you could tell me about this.
That should be pure class A, not tube class A. That's a typo, can you show me to the description so that I can change it?
 
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Jul 18, 2021 at 8:36 AM Post #44 of 49

Nick63

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That should be pure class A, not tube class A. That's a typo, can you show me to the description so that I can change it?
It is possible Yulong itself did not make or provide the descriptions on these sites. Here are the ones I read.
This is on Shenzhen Audio's site, but it appears to be Yulong's promo for the theDac. It says there: "high power tube amplification". https://shenzhenaudio.com/products/...2-32bit-768khz-decoder?variant=39971285991575

The one I first quoted that reads: ""high-power tube Class A amplification circuitry" is on a release about the dac. It also says : "Powerful tube Class A amplification circuit,"
https://www.gizaudio.com/yulong-announces-da-1-latest-all-in-one-desktop-audio-solution/

Whether Yulong had any direct input for these descriptions is not clear to me, but either way I appreciate you clarifying the tech.
 
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