REVIEW: JHC-A2 DAC/amp very interesting unique product
May 19, 2010 at 2:02 AM Post #16 of 41

jalyst

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Isn't that pretty much what is happening here already? Unless you use USB, there doesn't have to be a PC involved. I just used that as an example because I have tons of music on my PC and I could let it go forever, then simply tap into it whenever I want.
 


yeah that is what's happening from what I can tell.
 
May 19, 2010 at 2:07 AM Post #17 of 41

jalyst

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buz, see the post above your for an example of the target market on this thing. That being said, it would be quite a bit more useful if it had a set of line level analog outputs on the receiver end, and included a 2nd power supply for that part as well. That way it could be used purely as a wireless DAC. I could see myself leaving the transmitter section connected to my PC and basically using the thing as a music streaming setup, to easily get music from the PC out to my living room system. I've suggested this to the maker of the product.

Some good ideas, most importantly imo is improving battery life....
A recharge dock instead of having to pull-out/put-in recharged batteries would be sweet too.
 
 
May 20, 2010 at 7:54 PM Post #19 of 41

project86

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Quick reply, I'll add more in depth comments to the main review when possible.
 
Someone asked about how this compares to the Audinst HUD-mx1. The mx1 also uses a Wolfson WM8740 chip for DAC. After much listening they sound pretty similar, but I have to give the edge to the Audinst as a DAC and to the JHC A2 as an amp. The JHC gives you slightly less detailed sound but it's more dynamic, and possibly a tiny bit more punchy in the bass area. The JHC also truncates the highest highs a bit which is good or bad depending on your source/music/headphones. In the end they both sound excellent. The Audinst of course has the advantage of being able to handle 24/96 and other high res music, which the JHC does not.
 
May 21, 2010 at 8:23 PM Post #21 of 41

pcomliu

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Wireless transmission bandwidth limited, if the bandwidth is large, to shorten distance communication.JHC  can only 16bit/48KHZ, also can do 24bit/48KHZ, but up to 50 meters distance, and high costs.
 
May 21, 2010 at 8:27 PM Post #22 of 41

cegras

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"The amp portion features the older but still nice Texas Instruments TPA6120A2"
 
Are you implying that age makes this chip bad?
 
May 22, 2010 at 4:50 AM Post #25 of 41

pcomliu

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about "The amp portion features the older but still nice Texas Instruments TPA6120A2,"
 
Hi Project86,
I'm sorry. I asked the engineer, the first IC is faulty, with the hot air removed, TPA6120A2 the bottom of a large pad, hot air welding may need to beat IC tools can not withstand high heat will stick the top part of the residue in the TPA6120A2 welding traces. I promise: I was using the spare parts are new. As it relates to personality and integrity.
 
May 22, 2010 at 5:22 PM Post #26 of 41

project86

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Quote:
"The amp portion features the older but still nice Texas Instruments TPA6120A2"
 
Are you implying that age makes this chip bad?




Not at all! I was simply pointing out the fact that it has been around for a while, but it is still a very high performance solution. As an example, if the DAC section used an ESS Sabre chip, I might have mentioned the fact that it was a fairly new chip. Same thought process. Anything to keep from just listing chip after chip.... that would make for a dry read.
 
Quote:
about "The amp portion features the older but still nice Texas Instruments TPA6120A2,"
 
Hi Project86,
I'm sorry. I asked the engineer, the first IC is faulty, with the hot air removed, TPA6120A2 the bottom of a large pad, hot air welding may need to beat IC tools can not withstand high heat will stick the top part of the residue in the TPA6120A2 welding traces. I promise: I was using the spare parts are new. As it relates to personality and integrity.



Hello again. I'm not exactly sure what you mean here, but I'll take a guess: did you think I was implying that you used an old 6120 chip? Like a pre-owned or used chip? That was not what I meant. I just meant that the chip has been available for a while, that's all. I'm aware of the special nature of the chip, as per this link:
http://sjostromaudio.com/joomla/index.php?option=com_content&task=view&id=43&Itemid=27&limit=1&limitstart=1
 
So if you thought I was suggesting you did anything wrong, I apologize for that. I think we have a bit of a language barrier here. But the chip is good and it performs quite well. In fact I think that the amp section is the best part of your whole product. Hope that clears it up a bit.
 
May 22, 2010 at 9:33 PM Post #27 of 41

pcomliu

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Sorry, my English is rather poor, I understand wrong.You say is correct, TPA6120A2 is indeed a very great high-power operational amplifiers. Also use it to make a high performance headphone amplifier.Also, I think AD8397 is a good choice, it is also suitable for low-voltage performance headphone amplifier and DAC. Particularly in the power supply voltage +-3.7V when driving less than 100 ohms headphones performance is also very good.
 
May 27, 2010 at 9:52 AM Post #28 of 41

jalyst

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Quote:
Wireless transmission bandwidth limited, if the bandwidth is large, to shorten distance communication.JHC  can only 16bit/48KHZ, also can do 24bit/48KHZ, but up to 50 meters distance, and high costs.


Yeah but theoretically it should still be possible to do 24/96 via 2.4Ghz so long as one stays close to the transmitter.
I mean, as long as one's close enough there should be plenty of bandwidth, so why not allow 24/96?
 
May 27, 2010 at 3:42 PM Post #29 of 41

project86

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Quote:
Yeah but theoretically it should still be possible to do 24/96 via 2.4Ghz so long as one stays close to the transmitter.
I mean, as long as one's close enough there should be plenty of bandwidth, so why not allow 24/96?



I think it was just a design choice in this case. They really advertise the range aspect of this device, and that would no longer be an option if the range was suddenly a lot less. Also, I've found that in my real world testing, many things can negatively affect the maximum range. If we were alreayd limited to a theoretical maximum of 50 meters with 24/96, we might see a real word minimum of 10 meters in some instances. Might as well build a hard wired unit in that case. I see your point though, but I think it would be a different unit in that case.
 
Which brings me to my next suggestion: Pcomliu, have you considered making a non-wireless version? The sound is quite good on it's own without considering the wireless aspect.
 
May 27, 2010 at 8:02 PM Post #30 of 41

pcomliu

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Non-wireless version? I do not consider, because there are many similar manufacturers. Technically should be better than the wireless version of the simple,Of course, not easy to do great products.But this is not my strong suit.
 

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