Toward higher end DACs

[manaox2]

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Originally Posted by infinitesymphony /img/forum/go_quote.gif I love that thread... Thanks for keeping it updated, granodemostasa.

oh wow, thanks and bookmarked!

 

[regal]

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Originally Posted by infinitesymphony /img/forum/go_quote.gif I love that thread... Thanks for keeping it updated, granodemostasa.

I had not seen that thread, thanks for posting.

 

[n_maher]

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Originally Posted by regal /img/forum/go_quote.gif all said was some people prefer discrete analog equipment.

No, that's not what you said, let me remind you...

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Originally Posted by regal /img/forum/go_quote.gif Exactly, it doesn't mater how little jitter there is if you have an opamp analog stage you basically have a glorified CMOY in your signal path. Thats why I could never understand why people will put a good discrete amplifier after something like a Lavry or Dac1. It explains why tube head amps are so well received now days; the tube's harmonic distortion masks the "cmoy" in their DAC. Nothing wrong with that but the sound should be much improved with a good analog stage. This is why people love Oritek or Zapfilter analog stages so much, no more CMOY!

I'm no expert on the English language but I'm pretty sure that anyone that reads those statements is going to see that you're not just implying but flat out saying that having any opamp in an analog output stage is inferior and not worth putting a good amp after. Care to clarify what you really meant?

Furthermore you still haven't answered my question so I'm going to ask it again.

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Originally Posted by n_maher /img/forum/go_quote.gif Please list the Wadias and Meridians that you've heard.

I'm especially curious since you think they all sound like a CMoys. And while you're at it, please explain to me what you think a "CMoy" is since you must know a fair bit of circuit design to be able to tell that the output stages in many DAC's are just glorified CMoys. I'd like a bit more technical analysis please

 

[regal]

Here is a Cmoy.

http://tangentsoft.net/audio/cmoy-tu...angent-sch.pdf


Add a few capacitors, invert, and we have the attached last bit of the DAC1 analog buffer stage.

And again I am not saying there is anything wrong with a Cmoy, a lot of people like the sound. I wish I did, because buying audio equipment would be much easier.

 

[Cauhtemoc]

Quote:

Originally Posted by regal Here is a Cmoy. http://tangentsoft.net/audio/cmoy-tu...angent-sch.pdf Add a few capacitors, invert, and we have the attached last bit of the DAC1 analog buffer stage. And again I am not saying there is anything wrong with a Cmoy, a lot of people like the sound. I wish I did, because buying audio equipment would be much easier.

While I agree with what you say, an opamp in a DAC often sound much better than in a portable amplifier. Things like power consumption is no longer an issue, the opamp drives much lighter loads, you can use a better layout, a better power supply, larger filter capacitors and better components, not to mention better opamps.

The DAC1 uses a standard opamp I/V converter, the same as in almost every other commercial DAC. While they often measure very good in terms of THD, many people can testify that a dedicated discrete I/V converter does indeed sound better.

 

[n_maher]

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Originally Posted by regal /img/forum/go_quote.gif Here is a Cmoy. And again I am not saying there is anything wrong with a Cmoy, a lot of people like the sound. I wish I did, because buying audio equipment would be much easier.

And again, still zero evidence that you've ever heard anything the likes of a Meridian or Wadia, which you've claimed sounded like a Cmoy.

And as Cauhtemoc correctly pointed out, the output stage of a DAC is subject to entirely different loading than a headphone amplifier not to mention that simply clipping out a portion of the output stage of the DAC one only tells part of the story as to how it is integrated into the rest of the design.

If you like discrete output stages great, but you should realize that there is exactly zero guarantee that the discrete stage is any better or worse than the opamp. They are, afterall, exactly the same thing really. One just packages all of the components into a tiny housing for easy of use.

 

[regal]

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Originally Posted by n_maher /img/forum/go_quote.gif They are, afterall, exactly the same thing really. One just packages all of the components into a tiny housing for easy of use.

I have been unable to find an IC opamp that is the same as this board I have installed on my PMD-100 AD1862 DAC.


ALL-FET DAC Audio Board


This analog stage sounds wonderful, better than the ML's I have heard. But I can't find a case that will fit my DAC and this board and still allow all the buttons on the DAC to be accesible. If I could find an IC opamp that would perform like this I would gladly switch for the convenience. Erno Borbely is a very well respected audio designer, note what he says in the description.



.

 

[Cauhtemoc]

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Originally Posted by regal I have been unable to find an IC opamp that is the same as this board I have installed on my PMD-100 AD1862 DAC. ALL-FET DAC Audio Board This analog stage sounds wonderful, better than the ML's I have heard. But I can't find a case that will fit my DAC and this board and still allow all the buttons on the DAC to be accesible. If I could find an IC opamp that would perform like this I would gladly switch for the convenience. Erno Borbely is a very well respected audio designer, note what he says in the description.

Borbely's board is basically a discrete opamp, discrete I/V converters usually mean something like this:

diyAudio Forums - Easy-to-build I/V stage

By the way, PMD100 + AD1862 is a killer combination.

 

[regal]

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Originally Posted by Cauhtemoc /img/forum/go_quote.gif By the way, PMD100 + AD1862 is a killer combination.

Opinions very on this but many believe that the PMD100 + AD1862 was the pinacle of digital conversion.

 

[infinitesymphony]

Audio Alchemy DDE v3.0?

 

[facelvega]

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Originally Posted by Cauhtemoc /img/forum/go_quote.gif While I agree with what you say, an opamp in a DAC often sound much better than in a portable amplifier. Things like power consumption is no longer an issue, the opamp drives much lighter loads, you can use a better layout, a better power supply, larger filter capacitors and better components, not to mention better opamps.

Quote:

Originally Posted by n_maher /img/forum/go_quote.gif And as Cauhtemoc correctly pointed out, the output stage of a DAC is subject to entirely different loading than a headphone amplifier not to mention that simply clipping out a portion of the output stage of the DAC one only tells part of the story as to how it is integrated into the rest of the design. If you like discrete output stages great, but you should realize that there is exactly zero guarantee that the discrete stage is any better or worse than the opamp. They are, afterall, exactly the same thing really. One just packages all of the components into a tiny housing for easy of use.

Sure, an amp section driving transducers doesn't behave as well as one just providing a line out, but I think Regal's point stands that at the price brackets we're discussing here, the producers could easily put in a more complex and potentially better-sounding amp circuit in their analog out section. It could hardly sound worse, and it would probably be cheaper to do than much of the digital-side trickery that separates more expensive dacs from cheaper ones. I don't think this is too much to ask from a potential high-end dac purchase, though of course not as important as testing and comparison.

 

[n_maher]

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Originally Posted by facelvega /img/forum/go_quote.gif the producers could easily put in a more complex and potentially better-sounding amp circuit in their analog out section. It could hardly sound worse, and it would probably be cheaper to do than much of the digital-side trickery that separates more expensive dacs from cheaper ones.

What evidence do you have to support anything that you just said?

How easily could a discrete output stage be implemented? How much better, at the same price point, could it sound? It's all well and good to propose stuff like this but it's a bit naive to think that companies like benchmark, lavry, etc, are intentionally doing it the wrong way.

 

[Faust2D]

I am a big proponent of discrete class A solid state or ever better tube output stage in DACs. Call me unfair but I really do not understand why some manufactures that charge several thousands of dollars for their DAC use cheap OP Amp in the output stages. When I see things like modded DACs or CDPs that cost 5K new, it does not sit with me well. IMHO you should not modding 5K DAC, there should be no need to do this.

 

[facelvega]

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Originally Posted by n_maher /img/forum/go_quote.gif What evidence do you have to support anything that you just said?

I didn't say anything that requires special evidence. There do exist more complicated and potentially better output circuits than the ones we've been discussing as "glorified cmoys," some companies do use them and therefore any company might. They don't cost very much more than cheaper output stages in terms of parts or research (as a likely percentage of a high-end dac's production cost), so they would probably be cheaper to implement than, say, advanced anti-jitter technology. Knowing this, it wouldn't be too much to ask if one decided only to consider options with such a circuit when shopping for a dac. Is there something in particular you think is wrong here, or overstated? Or are you just annoyed with Regal and taking it out on anyone who supports his perhaps overstated point?

Quote:

How easily could a discrete output stage be implemented? How much better, at the same price point, could it sound? It's all well and good to propose stuff like this but it's a bit naive to think that companies like benchmark, lavry, etc, are intentionally doing it the wrong way.

I never said anything about discrete output stages, there are plenty of better opamp implementations out there too. However, I'd say discrete could be implemented fairly cheaply, for instance that discrete semi-portable Xenos amp was not much more expensive than a comparable opamp-driven one. To make it really sound clearly better, of course, one would want to spend more on it, but this is certainly doable within a profit margin, as some companies are making profit doing just that. Personally, I think that improved opamp-based outputs would likely be more cost-effective than going discrete except for the most expensive dacs, and from your previous posts, it seems you do as well.

And I already explained why I think benchmark, lavry, etc. made the decision not to build in more complex output stages. It would be naive to think that they would spend time and money on something like "better analog output stage" when they can spend it on "UltraLock (TM) clock systems" or CrystalLock (TM) - jitter elimination circuitry," which are far more likely to sell units and elicit gushing reviews.

 

[Faust2D]

Rant---

IMHO good output stage can make or break a DAC. Lots of the new up-over-under sampling is just marketing to sell new DACs. Just look at TDA1451 or TDA1453 DAC designs that sound superb.

End Rant---