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  #31  
Old 05-18-2012, 03:12 AM
SoNic67 SoNic67 is offline
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Just an example of what it should have the output stage - look inside my Denon DVD-2930.
The lower board is the DAC part. You see the DAC chips (right side), followed by two OpAmps and a bunch of capacitors. At the end (left side) there are the muting (anti-popping) transistors.
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  #32  
Old 05-18-2012, 05:16 AM
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That looks promising, but I don't see on the board any serious OpAmps on RCA outputs, so I am not convinced of the final audio quality.
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Originally Posted by SoNic67 View Post
Just an example of what it should have the output stage - look inside my Denon DVD-2930.
The lower board is the DAC part. You see the DAC chips (right side), followed by two OpAmps and a bunch of capacitors. At the end (left side) there are the muting (anti-popping) transistors.
I'm in the other camp completely. Discrete output stages are the way to go for quality output from a DAC, not opamps. IMHO opamps are a compromise where the designer doesn't want to go to the effort (or expense) of designing a proper output stage, and the picture of the output stage that you've posted above is a perfect example of such a compromise.
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  #33  
Old 05-18-2012, 05:43 AM
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Also, it is worth noting that this DAC uses a PCM5102 which is a voltage output DAC rather than a current output DAC, therefore it uses no I/V stage and does not require opamps nor a discrete output stage.

Based upon the above, it's a bit harsh to write-off the Dragon based upon assumptions made after viewing a photo
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  #34  
Old 05-18-2012, 05:42 PM
SoNic67 SoNic67 is offline
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I don't see any OpAmps on the RCA outputs for that DAC. Even if you are right about the DAC, the PCM5102 has a THD+N of -93dB (with a possible worse case scenario of -83dB). Not even 16 bit real audio quality (that would be -96dB). Sure, it can "gulp" 32 bit, but the analog side is not capable of more than 15-16 bit... the rest to those 32 bit is plain noise and distortion.
The PCM5102 needs on output a load of 10kohm or more. Less than that and the output is garbage. You need at least a buffer there, for those headphones.

As for OpAmps: You need reconstruction filters at the output. You need virtual ground impedance of curent output DAC's. You need a buffer for following stage/headphones.
None of this can be done properly without an OpAmp. All the DAC manufacturers show analog stages with OpAmps in their falsgship DAC datasheet pages. This include Texas Instruments, Analog Devices, Asahi Kasei, Cirrus Logic, Wolfson Micro, ESS (Sabre)...

Last edited by SoNic67; 05-18-2012 at 05:55 PM.
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  #35  
Old 05-18-2012, 09:07 PM
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As for OpAmps: You need reconstruction filters at the output. You need virtual ground impedance of curent output DAC's. You need a buffer for following stage/headphones.
None of this can be done properly without an OpAmp. All the DAC manufacturers show analog stages with OpAmps in their falsgship DAC datasheet pages. This include Texas Instruments, Analog Devices, Asahi Kasei, Cirrus Logic, Wolfson Micro, ESS (Sabre)...
Sorry but I disagree. None of my audio-gd DACs have opamps full-stop... They are discrete all the way. They are sonically excellent without an opamp in sight. Can I suggest dropping Kingwa an email and telling him to replace his discrete output stages with opamps? I'd love to see his reply. . There are many ways to skin a cat.

Again, I'd strongly suggest investigating the above DAC chip and overall DAC architecture before publicly writing-off a DAC based upon speculation and assumption. In my personal experience Musiland make excellent bang-for-buck gear. They are not some 'fly by night' company trying to sell crap products, and rest assured that their engineers are not stupid nor oblivious to the requirements of designing a DAC.
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  #36  
Old 05-19-2012, 05:50 AM
SoNic67 SoNic67 is offline
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You go by what Musiland engineers do, I go by what TI/BB, AD, AK, WM, CL, ESS engineers do.
As for discrete stages instead of OpAmps... they are poor implemented in 80% of cases (exception is maybe John Hardy 990C ones) and perform below of the level of a modern OpAmp. Been there, done that.

In the end... I agree to disagree.
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  #37  
Old 05-19-2012, 05:59 AM
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Originally Posted by SoNic67 View Post
You go by what Musiland engineers do, I go by what TI/BB, AD, AK, WM, CL, ESS engineers do.
As for discrete stages instead of OpAmps... they are poor implemented in 80% of cases (exception is maybe John Hardy 990C ones) and perform below of the level of a modern OpAmp. Been there, done that.

In the end... I agree to disagree.
Indeed, we can agree to disagree regarding what it best. Each to their own

However, if you had checked the spec sheets of this DAC chip, you would see that there is no need for opamps with the PCM5102 (as I mentioned earlier) hence Musiland are in the right and deserve none of your criticisms regarding improper design. Musild have designed it EXACTLY in accordance with the TI specification sheet. They are not stupid! I think it is important that this assertion is corrected, as I'd hate for a potential purchaser of this budget DAC to do a google search for information, find this thread, and assume that there is some flaw in the design of this DAC (which is clearly not the case).

http://www.ti.com/product/pcm5102

You will note the line outs DIRECTLY off the DAC chip due to the 2VRMS outputs which do not necessitate an output stage.

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  #38  
Old 05-19-2012, 06:50 AM
SoNic67 SoNic67 is offline
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Like I said before, look at the specs!
It REQUIRES 10kohm output (or more) impedance!!! Unless you have headphones that have that value you NEED output buffers.
Plus, the chip itself is a cheap one, capable of THD=-93dB - that is not even 16 bit performance (16 bit equals -96dB). Probably the lack of output active filters leads to that result too.
32bit snake oil.
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  #39  
Old 05-19-2012, 09:22 PM
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Like I said before, look at the specs!
It REQUIRES 10kohm output (or more) impedance!!! Unless you have headphones that have that value you NEED output buffers.
You'd better get in touch with TI then and correct them. The detailed spec sheet gives full implementation and circuit information and does not specify opamps in any way, shape or form. Either someone at TI has royally stuffed-up, or this DAC chip functions just fine as per TI's own implementation information.

I've also just realised that the JKDAC32 uses this exact DAC chip and it is one of the better DACs that I've heard in this price range, and it has... wait for it... no opamp (or discrete equivalent) output stage. John Kenny (DAC designer) is no fool either. Info and reviews below. John is clearly doing something right here, despite the meagre cost and specs of this DAC chip:

https://sites.google.com/site/hifacemods/home-1/Options

http://www.6moons.com/audioreviews/johnkenny2/1.html

http://www.enjoythemusic.com/magazin...c_shootout.htm
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  #40  
Old 05-19-2012, 10:50 PM
SoNic67 SoNic67 is offline
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How about you scroll to page 4 and 25 in their datasheet and read about output impedance?

At THD+N= -93dB (15 bit performance) is nothing spectacular. Regardless what people paid to say differently say. Or they are just taken by the "32 bit" marketing crap.
I see that you have audio-gd Ref 5 (4xPCM1704) as DAC... Can't belive that you can even compare that with the cheap toy from above.

Last edited by SoNic67; 05-19-2012 at 11:02 PM.
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  #41  
Old 05-19-2012, 11:32 PM
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budgophille budgophille is offline
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I'm in the same boat as the OP, I am also in the market for a DAC. My budget may be a little higher, but not by much. I had considered this: http://www.kingrex.com/productimg.aspx?id=22
But I don't know that it's that much different from the Dragon doodad that was mentioned a couple of pages ago. I heard a Matrix Mini at the fest, and was fairly satisfied with that, but I did want something that would go up to 24/196 through USB, but I do have a 3.5 glass to Toslink coming out of my XPS laptop, and according to the sound settings, I can set my output to that.

I had a couple of questions as well, if you guys don't mind me jumping in here on this thread....
1. I have seen quite a few DAC's with BNC outputs, what's up with that? I'm guessing they might connect to some equipment I can't afford, or would it be more for a commercial application.
2. In looking at the nudies of most of the DAC's here, it just doesn't seem like there's that much to them, compared to say... the MDHT Havana or Paridisea. Is that because they are more in the non-upsampling tube category?
3. Is there are way to search for DAC's on AK? I've tried with "DAC", Dac, "USB+DAC" to no avail. I guess it's a four character min in the Boolean operators?
Thanks so much for any insight on my hodge-podge of questions. Jon
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  #42  
Old 05-19-2012, 11:33 PM
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Quote:
Originally Posted by SoNic67 View Post
How about you scroll to page 4 and 25 in their datasheet and read about output impedance?

At THD+N= -93dB (15 bit performance) is nothing spectacular. Regardless what people paid to say differently say. Or they are just taken by the "32 bit" marketing crap.
I see that you have audio-gd Ref 5 (4xPCM1704) as DAC... Can't belive that you can even compare that with the cheap toy from above.
I understand what you're saying about the specs... but that doesn't change the fact that several manufacturers have designed DACs using this chip, in accordance with the TI spec sheet with NO output stage/opamps, and they perform perfectly well. I haven't heard the musiland DAC but I have heard the JKDAC32 as mentioned earlier and it is very very good for the money with excellent sonic performance. If there was some fundamental issue with implementing the chip in this way, surely there would have been widespread issues by now? A JKDAC32 was sent around on a tour of Australia recently, and nobody had issues running this DAC on a wide variety of systems (from mild to high-end stuff).

That's my beef here... asserting that something is wrong or can't work when there are demonstrated examples of it working just fine, in accordance with TI's own implementation recommendations.

And for the record, I haven't once tried to compare the Musiland DAC to my own DAC... it's irrelevant to the discussion at hand as the PCM1704UKs do require an output stage (which is 100% discrete in this instance, no opamps here).
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  #43  
Old 05-19-2012, 11:41 PM
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Originally Posted by budgophille View Post
I'm in the same boat as the OP, I am also in the market for a DAC. My budget may be a little higher, but not by much. I had considered this: http://www.kingrex.com/productimg.aspx?id=22
But I don't know that it's that much different from the Dragon doodad that was mentioned a couple of pages ago. I heard a Matrix Mini at the fest, and was fairly satisfied with that, but I did want something that would go up to 24/196 through USB, but I do have a 3.5 glass to Toslink coming out of my XPS laptop, and according to the sound settings, I can set my output to that.

I had a couple of questions as well, if you guys don't mind me jumping in here on this thread....
1. I have seen quite a few DAC's with BNC outputs, what's up with that? I'm guessing they might connect to some equipment I can't afford, or would it be more for a commercial application.
2. In looking at the nudies of most of the DAC's here, it just doesn't seem like there's that much to them, compared to say... the MDHT Havana or Paridisea. Is that because they are more in the non-upsampling tube category?
3. Is there are way to search for DAC's on AK? I've tried with "DAC", Dac, "USB+DAC" to no avail. I guess it's a four character min in the Boolean operators?
Thanks so much for any insight on my hodge-podge of questions. Jon
Jon, what's your exact budget?

If you can stretch it, the audio-gd NFB3.1/3.2 is an excellent entry-level DAC. If you have any intention of using USB via PC, the 3.2 is the way to go (asynchronous USB). Fully discrete analogue stages. I had the NFB3 (earlier version) and it was fantastic! I did order the DIR9001 receiver board though (24/96 vs 24/192 for the WM8805) as the DIR9001 offered slightly greater resolution and less colouration.

http://www.audio-gd.com/Pro/dac/NFB3-2011/NFB3.1EN.htm



I'm also a big fan of the Schiit Bifrost. Lovely DAC!
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  #44  
Old 05-21-2012, 03:24 PM
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Thanks for the info guys! My budget is roughly $500. I'm selling my Yammy M2 amp, to make room and $ for a DAC. I'll look in to this audio-gd NFB3.1-2, I had initially had my heart set on USB capabilities, but since my laptop (which will be my main source) has the Toslink out, it's not a deal-breaker. I suppose if I ever get around to building a music server, it may be needed then, but I've never been known for over-planning.

I have also heard good things about the Emotiva XDA-1, for an entry level model. Certainly a good price for something with a remote...
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  #45  
Old 05-21-2012, 03:35 PM
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I have also heard good things about the Emotiva XDA-1, for an entry level model. Certainly a good price for something with a remote...
I'll stick to my guns and second that.

In a market this dynamic, I advocate buying good performance and getting acclimated to the medium and all it's tricks and tips, rather than buying higher performance that may be entry level in a short time for 2-3x the price.

The cutting edge cuts too deep into my wallet
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