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Info & review(s): Linnenberg Audio udc1, asynchronous USB DAC

post #1 of 46
Thread Starter 

Hi all,

 

After a long search for a truly neutral, honest and transparent DAC for a reasonable price I've come across the Linnenberg Audio udc1 (listprice €1260).

http://www.linnenberg-audio.de/html/udc1.html

(not to be confused with Lindemann which also has a DAC, though that one doesn't look very interesting to me)

I've just bought the udc1, it will hopefully arrive somwhere mid/end next week.

Couldn't find anything about the udc1 on this forum (not much on the rest of the Internet either) so I thought I'd start a thread about it with information and later a review.

If anybody else here has heard this DAC or knows more about it please share.

 

 

 

UDC1_1.gif

 

Not that looks matter much to me, I do really like the clean minimalistic pro look of the ucd1.

I've never liked "hi-fi" looking equipment personally, probably due to more of a studio background.

 

 

UDC1_Rear.gif

 

And minimalistic it is.

Only a powerchord and USB 2 input and 2 balanced XLR outputs.

Which is perfect for me, I don't need anything else.

Adding S/PDIF inputs only brings extra costs and often degraded performance when the USB is converted to S/PDIF first instead of directly to I2S.

The USB input is the asychronous USB M2Tech hiFace OEM board (up to 24bit 192kHz bitperfect with kernel streaming and wasapi drivers) which outputs I2S, making the DAC the master clock and giving very low jitter.

Since there are no S/SPIF inputs it seems to me there doesn't need to be any jitter cleanup etc, and there is no ASRC, giving a very pure digital signal path.

 

 

UDC1_inside.gif

 

Design, construction and parts quality all seem very high and pure.

Some more info about the design:
The USB connector is galvanically isolated from the rest of the circuit by i-couplers and its own floating power supply.

The incoming sample rate is up sampled to a fixed rate of 192 kHz before entering the DAC chip. (I'm assuming this to be a synchronous upsampler)

DAC chip is the Burr Brown PCM1794a. (which we also find in for instance the April Music Eximus DP1, which also has async USB and a 192kHz upsampler btw, though also a much higher price and many additional features)

 

 

UDC1_Analog.gif

 

I/V / output stage is completely passive.

From the Linnenberg website:

"A passive I/V converter consisting of 0.1% precision resistors and the ultra low noise dual monolithic transistor SSM2212 is the perfect link between PCM1794A and the output buffers. This arrangement is absolutely free from slew rate induced distortions, provoked by high frequency out of band noise originating from the actual digital - analogue – conversion process."

"The subsequent gain and passive I/V stage is almost similar to the one used in the cdp3E. This discrete Class A signal path employs only the latest high quality parts from Zetex, Analog Devices and National Semiconductor. The output stage of the udc1 drives cables of any length as a result of the excellent wideband diamond buffer with 0.25A current capability. All voltage regulators are sourced exclusively from the leading specialist supplier (Linear Technology) with ultra low noise specifications (20uV).
No opamps. Zero feedback. Just music."

 

Now this output stage looks very attractive to me.

I don't know much about output stages and I/V conversion, but have been reading up on it a lot lately.

I've read that opamps can have trouble with the very strong high frequency noise comming of delta sigma DACs before filtering (which is actually stronger than the audio you do want). And that this could be partly to blame for harshness / treble glare / exaggerated dynamics/transients I know all to well from some other DACs.

I'm hoping this output stage will give true dynamics. Fast and exciting when the recording is, laid back and slow when the recording is.

Keeping my fingers crossed.

 

 

It looks to me that the designer, Ivo Linnenberg, has a very pure, skillfull, perfectionistic and rational approach.

I can really appreciate and identify with this.

I also spoke with him on the phone shortly for my order (very nice man btw), and amongst other things he told me he has affinity with the studio world.

That tells me more good things.

And it's just refreshing to see such a pure DAC.

The more I learned about how DACs are actually constructed the more I saw all the imperfections and nonsense.

Weird filter designs like minimal phase filters and apodizing filters, NOS DACs, ASRC and other "jitter reducing / removing" schemes that make no sense to me (an ASRC does not remove the jitter, it keeps the errors but simply gives it a different name), and many other marketing hypes.

None of this in the udc1.

 

The specs are modestly stated.

Frequency response: 1Hz - 24kHz +0.1dB -0.5dB
Distortion and noise: <0.01% 10Hz - 20kHz at -10dB
Output level: 4V rms balanced
Output impedance: 150 Ohms
Mains voltage: 115V, 230V factory set
Dimensions (H x W x D): 55 x 165 x 224 mm

 

At first glance the THD+noise of <0.01% looks a little on the high side.

But looking better you can see that it's specced at -10dB and for 10Hz to 20kHz and we need to remember that this is at 192kHz.

Most other DACs have their THD+N stated for a 1kHz sine at 0dB at 44.1kHz.

I've looked at the spec scheet for the PCM1794a, and it states that for 44.1kHz the THD+N is 0.0004% typical and 0.0008% max, all for full scale input.

At 192kHz the THD+N is 0.0015% typical, max is not stated but I logically assume it to be 0.003%.

As for most (all?) delta sigma DACs the THD+N is roughly a fixed value above / follows the theoretical THD+N of 24bit digital audio (it's roughly a straight line from the stated THD+N at 0dB to the 100% THD+N at the stated dynamic range, which point is between -127 and -132dB for the PCM1794a), we can calculate roughly the THD+N max at the -10dB stated in the specs for the Linnenberg udc1.

Doing the calculation finds roughly 0.01% THD+N max at -10dB at 192kHz for the PCM1974a. Exactly the same as in the specs for the udc1.

It's nice when things work out haha :)

So that tells us there's nothing to worry about here, and indicates the passive output of the udc1 also measures perfectly.

(edit: my calculations here are not correct. but the <0.01% THD+N stated spec is from actual measurement of the udc1)

 

 

I could not find any reviews of the udc1 on the Internet yet.

But there is a review by 6moons of the Linnenberg cdp3E CD player, which uses the same PCM1974a DAC chip and almost exactly the same passive I/V / output stage. I'm guessing it sounds very similar to the udc1.

6moons gave it a raving review on sound quality, saying it is better than the Weiss DAC2 and Burson HA160D.

http://www.6moons.com/audioreviews/linnenberg/4.html

Here are some extracts:

 

"cdp3E vs. Weiss DAC2: The Linnenberg fleshed out and texturized what the Weiss left drier, starker and paler. Quite matched on raw detail even though the cdp3E held a small advantage, the truly decisive factor was the legacy machine's greater image/tone density. Without any valves in the signal path, these qualities added up to what one usually expects from glowing bits whilst avoiding their liabilities. Transparency itself is ghostly. In more ways than one you see right through it. To mistake a virtual for a real performer without the aid of sight needs something extra, even compensatory. Think of it as incarnation factor. It turns ghosts into believable presences. For that our hifi must grab us on a nearly instinctual gut level far away from the mind. There dynamics certainly factor highly but during playback in the home they hardly ever approach realistic breadth and the true violence of live peaks. What's left then? However you define it, that's what made up the core difference between Linnenberg and Weiss."

 

"cdp3E vs. Burson HA160D: This juxtaposition inverted the above. Very well matched on that—flesh & blood, incarnation factor, your term—the German had the superior ambient retrieval. This micro detail wrapped itself around performers to extricate them to a higher degree from the soundfield to become nearly freestanding entities. While this freestanding illusion never comes off fully, the cdp3E went just a bit farther than the HA160D. The sense of presences interacting with defined recorded space was more acute. In declining sequence of excellence, it thus was Linnenberg, Burson, Weiss. The first two shifted an important dividing line. Lesser albums apparently flat dimensionally and tonally would still sound flatter than their more masterful peers but no longer flat per se. The more incarnation is in place, the broader the scope of CDs or music files becomes that can sound very satisfactory. This is key to enjoying a library that's built from the music up rather than the sound down. The cdp3E brilliantly checked off all the usual audiophile attributes centered around resolution. More importantly, it began steadfastly on the other foot of physicality and substance."

 

"Since my embrace of computer audio in early 2010, the Linnenberg became the first legacy player I've met—or let into the house—which suggests that the rationale or justification for its kind hasn't entirely expired yet. For the cdp3E it has most certainly run out on features (cough) but not on performance. To hard-boiled hifi fanatics that could be sufficient. Softening the scratchy hair shirt is the very attractive €4.500 sticker for a better than €3.000 Weiss converter + CD/Pro transport with custom servo board and all European manufacture."

 

 

 

Well that wraps up the info I could find and my thoughts on the udc1.

As you can read, I'm already raving about this DAC before I even heard it :)

It's because I feel well enough educated this time to make an assumption on what makes a good DAC, and had been fantasizing about how my ideal DAC would be constructed. I was even considering building my own DAC.

Didn't really want to go down that road as it would take a lot of time in research and the potential for error due to inexperience would be high.

But then I found this DAC, almost exactly how I fantasized my ideal (but reasonable cost) DAC to be like.

Asynchronous USB to I2S to PCM1794a, clocked from a low jitter clock, to passive I/V. All with a high quality power supply and parts. Only I would have personally done upsampling on the computer (will still do this) but the built in upsampler of the udc1 is kind of like a bonus that will come in usefull at times.

I'm sure that had I tried building it myself (based on a collection of DIY designs available online) it would have been nowhere near as well done as this.

 

But the proof is in the pudding :)

I'll let you all know how it actually sounds when I get it.

I hope I will not have to give another dissapointing review like with the Lavry DA10 and Yulong D18.

But I strongly suspect that won't be the case this time.

 

 

Btw. I thought it might interest some of you here that there is also a fresh new headphone amp available from Linnenberg Audio, the spa1 (listprice €970).

http://www.linnenberg-audio.de/html/spa1.html

Perhaps a good partner for the udc1?

Not interested in this myself as I've switched to speakers only for the moment (Klein+Hummel O300 and a very big high ceiling great sounding room. Thought I'd better put all my money in one great speaker setup than spread it around and have a less great speaker + less great headphones setup)

 

Disclaimer: I'm not affiliated with Linnenberg Audio (or any other audio company for that matter) in any way.

I'm thinking about why I'm writing this info and soon to be review down.

I guess I've started to feel involved with this online community after spending countless of hours reading reviews and discussion here, first about headphones and lately about DACs. Perhaps sharing the results of my DAC search can help some with their search.

Combined with excitement about my comming new DAC and there you have it :)


Edited by slackman - 1/10/12 at 10:21am
post #2 of 46
Thread Starter 

.


Edited by slackman - 1/14/12 at 8:28am
post #3 of 46

Where did you purchase the DAC and how much for? I am awaiting your impression impatiently. I loved the way you did  that i nthe D18 thread.

post #4 of 46

6moons gives everything rave reviews. And especially when comparing cheaper stuff to more expensive stuff, there's always this, "for 1/10 the price, this is a terrific bargain" bit in there.

 

"Doing the calculation finds roughly 0.01% THD+N max at -10dB at 192kHz for the PCM1974a. Exactly the same as in the specs for the udc1.

It's nice when things work out haha :)

So that tells us there's nothing to worry about here, and indicates the passive output of the udc1 also measures perfectly."

If anything, you should be more worried. Because the real, measured specifications of the whole DAC will never be as good as the on-paper specifications of the isolated dac chip. If it is, then the DAC wasn't measured in the real world.

 

Marketing talk taken from any audio manufacturer's website will always persuade consumers to part with their money, making things sound like a bigger deal than they really are: "All voltage regulators are sourced exclusively from the leading specialist supplier (Linear Technology) with ultra low noise specifications (20uV)."

 

Yea, probably bog standard LT317/337 regulators. 20uV is hardly low noise. Regulator noise performance must always be spec'ed with the frequency range; all regulators do a poorer job as you go up higher in frequency. Stating just that number doesn't mean anything at all. Just like how you wouldn't spec a 4" full range speakers to be 30Hz->20KHz without the +/- dB. Sure, they can 'do' 30Hz, but at what, -30 dB?

 

Good regulators are in the nV noise region.

http://www.paulhynesdesign.com/page6.html

"Settling time in all error amplifiers is < 10 nanoseconds and wideband noise spec 2 nanovolts root HZ. "

 

All i'm saying is this: don't believe everything you read, especially not on a manufacturer's site. Just because it has this or that doesn't mean it must be good.

post #5 of 46
Thread Starter 
Quote:
Originally Posted by Szadzik View Post

Where did you purchase the DAC and how much for? I am awaiting your impression impatiently. I loved the way you did  that i nthe D18 thread.



I purchased it directly from Linnenberg Audio (the only way I believe).

http://www.linnenberg-audio.de/html/ordering.html

You can also find the price list there: http://www.linnenberg-audio.de/html/downloads.html

 

I'm glad you liked my review of the D18, but I actually feel it was kind of a mess haha :)

It's easier to first hear the things a new DAC does not do wrong which previous DACs did wrong, because you can identify those errors more easily since you recognise their sonic signature / know what to listen for. (the honeymoon period)

But it takes more time to hear and put in perspective new things that you're not yet familiar with a DAC does not do right (for me).

For me it meant that I became progressively less happy with the D18.

I'm going to try to be more careful with this for the udc1 review (though this aspect will always be around to some degree it seems to me), and I'll have a longer period before I have to decide to keep it (and hopefully I will and have an even longer period to get to know it's sound or non sound)

 

 

post #6 of 46
Quote:
Originally Posted by slackman View Post





I purchased it directly from Linnenberg Audio (the only way I believe).

http://www.linnenberg-audio.de/html/ordering.html

You can also find the price list there: http://www.linnenberg-audio.de/html/downloads.html

 

I'm glad you liked my review of the D18, but I actually feel it was kind of a mess haha :)

It's easier to first hear the things a new DAC does not do wrong which previous DACs did wrong, because you can identify those errors more easily since you recognise their sonic signature / know what to listen for. (the honeymoon period)

But it takes more time to hear and put in perspective new things that you're not yet familiar with a DAC does not do right (for me).

For me it meant that I became progressively less happy with the D18.

I'm going to try to be more careful with this for the udc1 review (though this aspect will always be around to some degree it seems to me), and I'll have a longer period before I have to decide to keep it (and hopefully I will and have an even longer period to get to know it's sound or non sound)

 

 



 

An honest mess it was :). I hope this one is less messy as you gain experience. 

 

This one is a bit too expesive for me, but I hope you like it. I will be buying a Metrum Octave DAC soon.

post #7 of 46
Thread Starter 
Quote:
Originally Posted by sorue View Post

6moons gives everything rave reviews. And especially when comparing cheaper stuff to more expensive stuff, there's always this, "for 1/10 the price, this is a terrific bargain" bit in there.

 

"Doing the calculation finds roughly 0.01% THD+N max at -10dB at 192kHz for the PCM1974a. Exactly the same as in the specs for the udc1.

It's nice when things work out haha :)

So that tells us there's nothing to worry about here, and indicates the passive output of the udc1 also measures perfectly."

If anything, you should be more worried. Because the real, measured specifications of the whole DAC will never be as good as the on-paper specifications of the isolated dac chip. If it is, then the DAC wasn't measured in the real world.

 

Marketing talk taken from any audio manufacturer's website will always persuade consumers to part with their money, making things sound like a bigger deal than they really are: "All voltage regulators are sourced exclusively from the leading specialist supplier (Linear Technology) with ultra low noise specifications (20uV)."

 

Yea, probably bog standard LT317/337 regulators. 20uV is hardly low noise. Regulator noise performance must always be spec'ed with the frequency range; all regulators do a poorer job as you go up higher in frequency. Stating just that number doesn't mean anything at all. Just like how you wouldn't spec a 4" full range speakers to be 30Hz->20KHz without the +/- dB. Sure, they can 'do' 30Hz, but at what, -30 dB?

 

Good regulators are in the nV noise region.

http://www.paulhynesdesign.com/page6.html

"Settling time in all error amplifiers is < 10 nanoseconds and wideband noise spec 2 nanovolts root HZ. "

 

All i'm saying is this: don't believe everything you read, especially not on a manufacturer's site. Just because it has this or that doesn't mean it must be good.



6moons does not easily say clearly that some DAC is better than the Weiss DAC2 (the only other DAC he's said this of that I'm aware of is the Eximus DP1).

He has preferred other DACs in the past because of things like "better body" or things like that, but also stated these DACs lost out in detail to the Weiss DAC2.

With the cdp3E vs Weiss, he said that the cdp3E actually has a small advantage over the DAC2 when it comes to raw detail. This on top of the "more fleshed out and texturized sound", and what I interpret him as saying a more believable realistic sound.

At least that's what I get from it..

Not saying it's the end of all reviews and everybody would agree, but since Srajan moved into his new room (his old one was too bad to not to color a lot I think) I tend to hold some value to his reviews (though not always to his preferences, but still his reviews make the sonics clear enough).

In any case he's a much much better reviewer than I'll be :)

 

I can't really agree with real world DACs not measuring as manufacturers specs.

I thought that manufacturer specs are often based on their evaluation boards?

And I've seen plenty of DACs meet manufacturer specs with convincing measurements.

It seems likely to me the specs stated for the udc1 are from actual measurement, and they're not written in a way to make it look impressive (if he wanted to do that than there are plenty of tricks to give a much higher number for THD+N)

 

As for the regulators.. not something I know much about ;)

I've given a link of this thread to Mr. Linnenberg, perhaps he will read about the 20uV without frequency range and add the frequency range spec if you're correct

Empty statement specs aren't a nice thing indeed in audiophile land where there's enough nonsense flying around to wade through already.

But the more convincing argument for build and parts quality came for me more from the 6moons review of the cdp3E and amp2S.

Not saying Srajan is likely to be a great technical expert (sampling theorem seems to not have sunken in with him yet for instance), but by now after all the hi-end gear he's taken apart he's surely more of an expert than me in parts and build quality.

 

I interpret the Linnenberg website and work as one of a passionate and proud man. Not a marketing machine.

Have gotten plenty of reasons to think so already, but could always be wrong.

The sonics will tell :)

 

post #8 of 46

Very interested to hear about this. At probably $1700 usd shipped, it's out of my league for now, but I can always aspire.

post #9 of 46
Quote:
Originally Posted by slackman View Post

 

I can't really agree with real world DACs not measuring as manufacturers specs.

I thought that manufacturer specs are often based on their evaluation boards?

And I've seen plenty of DACs meet manufacturer specs with convincing measurements.

It seems likely to me the specs stated for the udc1 are from actual measurement, and they're not written in a way to make it look impressive (if he wanted to do that than there are plenty of tricks to give a much higher number for THD+N)

 

Not saying Srajan is likely to be a great technical expert (sampling theorem seems to not have sunken in with him yet for instance), but by now after all the hi-end gear he's taken apart he's surely more of an expert than me in parts and build quality.

 

I interpret the Linnenberg website and work as one of a passionate and proud man. Not a marketing machine.

Have gotten plenty of reasons to think so already, but could always be wrong.

The sonics will tell :)

 


"Plenty of DACs meet manufacturer specs" -> i think you misread what i said. I meant to say the DAC chip specifications, as per the datasheet, are only on paper. In practice, that elusive THD datasheet specifications number is seldom met.

 

Expert in parts and build quality? Srajan does not design audio gear for a living. He is an expert reviewer, not an expert electronics designer. You cannot tell how well something is designed, much less how it sounds, just based on how good it LOOKS on the inside, and what parts it uses. Using a ton of capacitors the way some brands do in the power supply section does not mean those caps are actually doing anything, at all.

 

Linnenberg, like any one else, is a business first and foremost. They are out there to sell stuff and make a profit. Without marketing, no one will know about your brand, your products, and no one will buy your stuff. It's not an idealistic world. Passion and enthusiasm alone does not make a successful business.

 

 I don't know where you're studying your material from, but if you want to read about audio design without all the marketing technoblabble, start learning from sites like diyhifi.org (the best diy resource IMO) or diyaudio

 

 

 


Edited by sorue - 1/6/12 at 10:29pm
post #10 of 46

Subscribed smily_headphones1.gif

post #11 of 46
Thread Starter 
Quote:
Originally Posted by sorue View Post


"Plenty of DACs meet manufacturer specs" -> i think you misread what i said. I meant to say the DAC chip specifications, as per the datasheet, are only on paper. In practice, that elusive THD datasheet specifications number is seldom met.

 

Expert in parts and build quality? Srajan does not design audio gear for a living. He is an expert reviewer, not an expert electronics designer. You cannot tell how well something is designed, much less how it sounds, just based on how good it LOOKS on the inside, and what parts it uses. Using a ton of capacitors the way some brands do in the power supply section does not mean those caps are actually doing anything, at all.

 

Linnenberg, like any one else, is a business first and foremost. They are out there to sell stuff and make a profit. Without marketing, no one will know about your brand, your products, and no one will buy your stuff. It's not an idealistic world. Passion and enthusiasm alone does not make a successful business.

 

 I don't know where you're studying your material from, but if you want to read about audio design without all the marketing technoblabble, start learning from sites like diyhifi.org (the best diy resource IMO) or diyaudio

 

 

 




Hi Sorue,

 

No I understood about the DAC chip specs on paper.

But I thought that those paper specs are based on the actual performance of the DAC chip in an actual circuit.

I thought that evaluation boards by the DAC chip manufacturers actually already reach these paper specs in reality?

In any case, the <0.01% THD+N for -10dB 10Hz-20kHz (at 192kHz sample rate) as in the specs for the udc1 are not taken directly from the Burr Brown paper specs as this figure is not in the paper specs for the PCM1794a.

I had to do the calculations as I wrote in my post to find what could be expected of this chip in a good implementation, and it just so happened that I arrived at the same figure as is actually stated in the udc1 specs by doing so.

It seems very likely to me that the specs for the udc1 are from actual measurements, but I'll ask the designer to be sure.

 

About Srajan not being a designer / great technical expert, yes that what I said too :)

But at least he got a good look at construction quality and parts, and is sure to know more about this than I do.

I'm not a designer / technical expert either. (Though I do consider myself an intelligent and well informed person.)

I'll try to take detailed pictures once I receive the udc1 so you and other people with technical knowledge can have a good look at the parts and design.

 

About the marketing stuff.

I'm not against marketing :)

Though I do get irritated from nonsense misleading marketing stuff (like saying minimal phase filters have better time domain behavior which is wrong, it's the opposite! Or NOS DACs having better impulse behavior which is completely false too.)

But I'm not reading such nonsense on the Linnenberg website, nor do I see it in his design.

Btw. I also read in the 6moons review that the designer, Dipl.-Ing. Ivo Linnenberg, does not make a full living out of this but does it out of passion (and for 20 years already).

His other income is stated in the 6moons review as lighting systems, hi-speed infrared cameras and motor controllers for industrial conveyor belts.

I do like the udc1 comming from such a designer, but it doesn't matter much to me actually.

I just stated this info out of interest in my post, and I do still think I wrote a correct picture.

But even if the udc1 was designed and built by a large commercial audio company, or in China etc, I'd still would have bought it.

The functional design is what attracts/convinces me.

(edit: Well what I wrote above is not completely true.. I do give some trust to actual implementation and build quality from a designer like this more than a big commercial designer or a just starting Chinese designer. But this is not the sole reason for the trust, the 6moons review on the other Linnenberg equipment does give some trust in these parts to me too)


Edited by slackman - 1/7/12 at 8:43am
post #12 of 46
Quote:
Originally Posted by slackman View Post



 

About Srajan not being a designer / great technical expert, yes that what I said too :)

But at least he got a good look at construction quality and parts, and is sure to know more about this than I do.

I'm not a designer / technical expert either. (Though I do consider myself an intelligent and well informed person.)

I'll try to take detailed pictures once I receive the udc1 so you and other people with technical knowledge can have a good look at the parts and design.

 

With detailed pictures we can see what parts are used, but we cannot tell how they are being, e.g. the real design/schematic. And that's the most important thing. If you don't know the schematics, you cannot say anything meaningful about the dac/amp. You won't know what this resistor is doing, what that transistor is doing, etc. Now of course, that is their intellectual property and they have every right to protect it. Besides, if you don't know electronics design, that schematics means nothing to you.

 

I honestly don't understand the point of asking the designer all these things, because you're not going to hear a honest critique of his own design. Would you objectively criticize your own product, if you knew you depended on selling these things to make a living? Conflict of interest is unavoidable.The answers that you are seeking will not be found from most, if not all, audio manufacturers who are out there peddling their wares.


Edited by sorue - 1/7/12 at 7:05pm
post #13 of 46
Thread Starter 

I asked the designer about the THD+N spec.

Here is his reply:

 

All the given data is measured and guarantied by design.
If you look at the PCM1794A datasheet, you will see that there is hardly any difference between 0dB and -10dB in the THD-figure.
TI measures this with the standard 3 opamp circuit (NE5534, LT1028) and a brickwall filter of 22 kHz.
This arrangement creates the marketing spec of 0.0004% THD, although not very real life, especially because of the very high out of band noise present.

>From this it is easy to see, that it is not possible to just "calculate" a THD figure @ -10dB.

The reason, we chose the -10dB level @ 44.1kHz @ 16bit is, that the average music level lies between -20dB and -10dB for a fully normalized (100%) recording.
This gives a real life THD figure of 0.01%, which is extremely good for an zero feedback amplifier.

It is not by chance that this is exactly the same number as for the cdp3E, because important resistor / current ratios in the circuit are the same too.

 

 

I also asked about the upsampler, if I was correct in assuming it is a linear phase "synchronous" upsampler.

And he confirmed this.

 

He also responded about the regulator and said that the published 20uV noise is for 10Hz to 100kHz bandwidth. The noise is lower in the audio bandwidth up to 20kHz.

Adding:

Furthermore, RC decoupling is used to preclude any interaction between the regulator and the audio circuitry again lowering the noise seen by the audio circuit.

There are no LM317 / LM337 regulators inside the udc1.

 

He also said one should not ignore:

the work it takes to put together a unique package which fits mechanically, electrically and sonically.
There is no problem to build something, where 11 voltage regulators (that’s the number of regulators in the udc1) consume the whole financial budget.
The question remains, if the product gets better. I doubt it.

 

 

That last part makes a lot of sense to me :)

 


Edited by slackman - 1/8/12 at 2:21pm
post #14 of 46
Furthermore, RC decoupling is used to preclude any interaction between the regulator and the audio circuitry again lowering the noise seen by the audio circuit.

This is hardly a big deal and it's common practice in plenty of equipment.

 

"The noise is lower in the audio bandwidth up to 20kHz."

Nope, the reason why you want high bandwidth is because the noise at those high frequencies can, and often will, affect the audio bandwidth. Again, no proper specifications. How low is low? Without numbers, it's all up in the air. LM317/337 is used metaphorically to represent all standard off-the-shelf 3 pin regulators. Which he is probably  using. Which is hardly low noise.

 

There is no problem to build something, where 11 voltage regulators (that’s the number of regulators in the udc1) consume the whole financial budget.
The question remains, if the product gets better. I doubt it.

This is strange to me. So is he doubting the 11 voltage regulators in his dac not making the dac better?

 

There is nothing difficult about throwing in tons of generic 3-pin regulators. It's cheaper and easier than designing a discrete, high performance regulator from scratch. Heck, there's the jung/sulzer (google: walt jung) discrete regulator which performs much better than any generic 3-pin regs and has been used for years in the diy and commercial circuit. It just costs more money and time to implement.

http://waltjung.org/Regs.html

 

Again, you won't find the answers you from people selling their wares.


Edited by sorue - 1/8/12 at 4:55pm
post #15 of 46
Thread Starter 
Quote:
Originally Posted by sorue View Post

Furthermore, RC decoupling is used to preclude any interaction between the regulator and the audio circuitry again lowering the noise seen by the audio circuit.

This is hardly a big deal and it's common practice in plenty of equipment.

 

"The noise is lower in the audio bandwidth up to 20kHz."

Nope, the reason why you want high bandwidth is because the noise at those high frequencies can, and often will, affect the audio bandwidth. Again, no proper specifications. How low is low? Without numbers, it's all up in the air. LM317/337 is used metaphorically to represent all standard off-the-shelf 3 pin regulators. Which he is probably  using. Which is hardly low noise.

 

There is no problem to build something, where 11 voltage regulators (that’s the number of regulators in the udc1) consume the whole financial budget.
The question remains, if the product gets better. I doubt it.

This is strange to me. So is he doubting the 11 voltage regulators in his dac not making the dac better?

 

There is nothing difficult about throwing in tons of generic 3-pin regulators. It's cheaper and easier than designing a discrete, high performance regulator from scratch. Heck, there's the jung/sulzer (google: walt jung) discrete regulator which performs much better than any generic 3-pin regs and has been used for years in the diy and commercial circuit. It just costs more money and time to implement.

http://waltjung.org/Regs.html

 

Again, you won't find the answers you from people selling their wares.


Seriously.. I'm beginning to find your negative questioning of the udc1 build quality a bit strange..

This is clearly a very high quality and pure design by an experienced and skillful designer.

If you're responding to this design in such a manner then surely there must be no commercial DAC out there that you trust no matter the price or builder.

I don't know a single DAC under 2000 euro which has a similar purity of design (the price range I've been looking at).

Not Anedio, not Audio-GD, etc.

I mean it's asynchronous USB to I2S, 192kHz synchronous upsampler (correctly done with linear phase), then to DAC. Pure I2S digital signal path that does not add jitter.

Then the top BB DAC chip the PCM1794a, then passive I/V and discrete class A output stage with 0 feedback. How pure can it get? I don't know another DAC that does this.

One of the proofs that it is excecuted will is the specs, they are great and they are from actual real-life measurement, stated clearly now by the designer as I've posted in the post you're replying to.

If you don't trust it go measure it yourself. But I don't think you're suggesting Mr. Linnenberg is lying right?

A badly implemented zero feedback discrete class A amp would not measure like this would it?

 

About the 11 voltage regulators. No you're reading his words wrong.

He's saying, surely you can use regulators with even lower noise specs, and you can use up the entire financial budget on these, but he doubts if the product would get any better by doing so.

And why is the info of 10Hz to 100kHz for the 20uV regulator not enough? It's exactly what you asked for so I posted it.

He also said it's 9uV for 10Hz to 20kHz, but this you should be able to calculate for yourself from the 20uV for 10Hz - 100kHz  bandwidth right?

 

And have you read the entire 6moons review on the cdp3E and amp2S?

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

Srajan quite clearly puts the Linnenberg equipment in the highest plane of quality.

 

Sorry if I'm understanding you wrong.

But it seems a bit disrespectful to me to start criticising the udc1 and designers intentions out of the blue like this. I don't see a good reason for it. (and trust me I'd join you in criticising if I did see a good reason)

First on specs, saying they're not real, where you were wrong (me too in my calculations, but not in that it is from acutual measurement)

And now on the wording of very low noise regulators. Your way of writing seems to hint in the direction that the udc1 must be a cheap (bad even?) design that's meant to make a lot of profit for the designer?

I'm not liking that way of talking about my new DAC without good reason wink.gif

 

 

Here are some more abstracts from the 6moons review where Srajan qoutes Mr. Linnenberg on the cdp3E and related matters so you can partly see how the designer thinks.

On SPDIF and DAC design:

"Although widely used and accepted, the S/PDIF communication protocol is not state of the art because it is a composite signal like FBAS in video."

"An outboard DAC as we see it should have an asynchronous USB input, Firewire or non-standardized I²S input and in that order. S/PDIF, AES/EBU or optical communications are actually not up to the task of delivering high-quality low-jitter audio. Having built very many different DAC topologies, I finally concluded that the advantages of paralleling DACs are ultimately only theoretical. They are more than offset by higher distortion plus more radiated interference within the analog section. To my mind this does not warrant buying 2 or 3 decibels more channel separation. I thus run a single BB 1794-A chip with fully balanced passive I/V conversion resistors—no op amps!—and a very accurate 3ps crystal oscillator."

 

Here some more texts by Srajan about Mr. Linnenberg and the cdp3E:

"Lest you think this capricious or ill-informed, Linnenberg had a very ambitious power DAC as early as 1994. While the German press was all over it as a pioneering project, it proved well ahead of its time in terms of consumer acceptance."

 

"The cdp3E benefits from a custom daughter board to modify the stock CD-PRO2 transport. All control logic firmware was custom-written to give Linnenberg full control over the critical transport servo parameters. This demonstrates high-level engineering that's not content with quality stock solutions, even one as proven as the CD-PRO2. The cdp3E upconverts the extracted Redbook signal three times prior to conversion. Then a digital filter applies another 8 times oversampling. Asynchronous sample rate conversion however is deliberately shunned as Ivo Linnenberg considers it an inferior approach to jitter reduction whilst causing amplitude distortion. I/V conversion, spurious noise filtering and the class A output driver are dual differential."

 

"The master clock and converter stage benefit from heavily regulated ultra low-noise supplies and the digital and analog section get their own discrete power toroids. The blue custom LED display—not the stock Daisy issue seen in most all other CD-PRO2 machines—runs in DC mode to avoid interference with the audio circuitry. The output stage generates 4V under full signal with a Zout of 470Ω."

- note, this 470Ω output is 150Ω in the udc1. Most other things about the cdp3E output should apply to the udc1 as well.

 

"As should be clear by now, Ivo's deliberate positioning of Linnenberg Audio as a low-volume destination for very specific customers allows him to be quite uncompromising."

 

And let's not forget that Srajan, an experienced audiophile with good surrounding equipment, gave a clear victory in all areas for the cdp3E over the Weiss DAC2.

So it surely isn't all empty words..

 

So I don't know what your experience and skill level is with high-end audio design or DAC design in particular.

But I'm guessing it's not the same as that of Mr. Linnenberg.

And I feel the udc1 and it's designer deserve some respect. There is probably a lot to be learned from it.

 

 

edit:

Mmm perhaps I owe your intentions an apology.

I just read things again, and I interpreted your posts as a bit of "bashing" on the design and designers intention, for which I could not see the reason.

But I now see that your intentions were perhaps to help me?

If that's the case then sorry for my tone!


Edited by slackman - 1/8/12 at 7:34pm
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