# D/A Converters



## stealthx32 (Oct 29, 2000)

I just bought a used JVC XL-Z431 (kinda off topic cuz it's a home audio component CD player), manufactured in 1990. It has a 1-bit DAC, and was wondering what you guys thought about the quality of it. I also have a Pioneer PD-102, with a PULSEFLOW 1-bit DAC...but it has lotsa trouble reading discs properly. It just sits there and buzzes.... I'm not sure how they really would sound on a decent system, cuz I'm running them through a sound card on my computer (violation #1) and then through some cheapass Altec Lansing speakers (violation #2), with a Kenwood car audio amp (violation #3) running a Kenwood passive subwoofer from a cheap home audio system (violation #4). Anyways, what ya all think? BTW, even though both are from the early 90's, both manufacturers still claim to use the same 1-bit D/A's (P.E.M. DD for JVC and PULSEFLOW for the Pioneer).

P.E.M. D.D. Converter 
The exclusive JVC P.E.M. D.D. (Pulse Edge Modulation Differential-Linearity-Errorless D/A) Converter is touted by media reviewers and audiophiles as one of the most accurate and musical 1-bit D/A converters available. The delicacy and subtlety of the music can be heard at all levels as it was meant to be. 
Some specs:
Pioneer
Frequency Response 2 - 20,000kHz 
Signal to Noise Ratio (EIAJ) 98 dB 
Dynamic Range (EiAJ) 96 dB 
Distortion (EIAJ) 0.005% 
JVC
Frequency Response: 2 Hz to 20,000 Hz
Dynamic Range: 98 dB
S/N Ratio: 106 dB
THD: 0.0022% (@ 1 KHz)
Channel Separation: 96 dB
Anyways, I'm just probably asking an unanswerable question. I'm probably just asking for past experiences.










[Modified by stealthx32, 3:22 AM 1-23-2002]


----------



## vwgtirob (Aug 16, 2001)

*Re: D/A Converters (stealthx32)*

If anyone can reliably distinguish between two DACs given a proper listening test with the ABX protocol, I'll give them $1000.


----------



## Scott P (Nov 13, 2000)

*Re: D/A Converters (vwgtirob)*

you set it up and I'll take that $1000
easy money.


----------



## vwgtirob (Aug 16, 2001)

*Re: D/A Converters (Scott P)*

Okay, here are the rules then:
Any two commercially-available DACs that you supply, and must be able to be driven from the same (digital) source
Frequency response must be flat (no special processing can be done, just a DAC)
Levels matched to within 0.1dB
The DACs must not make any audible noise when fed digital zero
Must get 12 of 12 trials correct
You fly out here, get 12 of 12 trials correct, and you earn $1000.


----------



## Jasonhouse1.8t (Dec 11, 2001)

*Re: D/A Converters (vwgtirob)*

I've seen it done at CES' before when I was managing at a local high end retailer(the car audio dept). In fact, I've heard it myself in both home and car applications. Ever hear of Krell? Trust me, all other things being equal, You'll HEAR the difference.


----------



## vwgtirob (Aug 16, 2001)

*Re: D/A Converters (Jasonhouse1.8t)*

The only things that are going to cause an audible difference between DACs are jitter and non-linearity.
I'd feed the DACs an extremely low-jitter source, so that's a non-issue unless they reclock and do it badly.
And non-linearity isn't an issue with any audio DAC I've ever seen recently. Some discrete R-2R and R ladder DACs with improperly matched resistors have had bad linearity, but I haven't seen any of those around in ages outside of some cheapo computer sound devices.
One-bit DACs are inherently perfectly linear (two points define a line), delta-sigma DACs have no problem in this area, and every commercial R-2R ladder DAC has superb linearity.
There are -no- other variables affecting the DAC output, nevermind any that would be audible.
Hell, I'll turn it into a bet and double the price:
If you get less than 7 of 12 correct, you give me $2000, if you get 7-10 correct, no money changes hands, and if you get 11 or 12 correct, I give you $2000.








I've done this before. No one has been able to tell the difference between my portable CD player's internal DAC, my outboard Soundstream/Krell DAC-1, my Apogee DA 1000, a borrowed Mark Levinson No. 36 Special Edition, and one of the listener's DACs with a tube output stage (I think it was a Cal. Audio Labs one).
No matter what the combination tried (all the combinations weren't tried, IIRC) no one got better than 6 out of 10. Most of these people were audiophiles, and one was a concert pianist.
The transport was a Sony DVP-S9000ES DVD player, playing various audio CDs, and the switching was done by an original ABX comparator. All the DACs were simultaneously connected to the digital input to reduce clocking problems and the switching was done in the analog domain.


----------



## JLJetta (Nov 24, 2001)

*Re: D/A Converters (vwgtirob)*

quote:[HR][/HR]Okay, here are the rules then:
Any two commercially-available DACs that you supply, and must be able to be driven from the same (digital) source
Frequency response must be flat (no special processing can be done, just a DAC)
Levels matched to within 0.1dB
The DACs must not make any audible noise when fed digital zero
Must get 12 of 12 trials correct
You fly out here, get 12 of 12 trials correct, and you earn $1000.[HR][/HR]​You should be careful.. ;-)
You have left out a few restrictions which if not controlled can lead to differences. Most minor, but I can think of at least two which would be dramatic, night and day differences. Nothing magical mind you, all easily measurable effects. I suggest you ask Arny to supply a few more "qualifiers".
As much as I could use a new chip, exhaust and shocks.. I suspect you'll cry 'cheating' before handing over the money.. So, I'll let you think about those above qualifiers to "cover yourself" first.. 
*grin*
---
Did you know that a Ferrari F360 and a Yugo drive the same?
It's true.
First you have to be on an absoluletely smooth road.. maintaining exactly 5mph.. and deaf.. and blind.. and .. well, you get the picture.


----------



## vwgtirob (Aug 16, 2001)

*Re: D/A Converters (JLJetta)*

quote:[HR][/HR]You have left out a few restrictions which if not controlled can lead to differences. Most minor, but I can think of at least two which would be dramatic, night and day differences. Nothing magical mind you, all easily measurable effects. I suggest you ask Arny to supply a few more "qualifiers".[HR][/HR]​Which? Note that I'm talking about commercially available DACs, so they wouldn't be likely to be miraculously misconceived. Several other details are taken care of by the standard ABX test protocols.
quote:[HR][/HR]
Did you know that a Ferrari F360 and a Yugo drive the same?
It's true.
First you have to be on an absoluletely smooth road.. maintaining exactly 5mph.. and deaf.. and blind.. and .. well, you get the picture. [HR][/HR]​If all you used a car for was going to the corner convenience store, they'd likely have identical performance. However, your analogy is faulty. Most of the things you pay extra for in a DAC, other then netting you warm fuzzies, don't make the DAC "work" any better if you're using your ear to judge. They might measure differently (although you'd be surprised at how minor the differences are between vastly different DACs) but your ear can't tell.
The careful engineering and artful design of the Ferarri makes a car that handles better, accelerates faster, sounds more refined, looks more beautiful inside and out, and feels better than the Yugo.
If you need the box on your shelf that the music passes through to be gold-plated, then that's fine, but you normally don't touch the DAC, and it normally just works, and there's nothing to stop you from hiding it.
A better analogy would be comparing a Honda Civic, and a gold-plated Honda Civic. They both work equally well in all aspects, but one costs much more.








If you need to spend $1000 or more on a DAC to truly enjoy it, maybe it's the price itself that causes the most additional enjoyment. And maybe that's worth it. Of course, knowing you have "the best" (i.e. pride of ownership) goes quite far to enhancing your experience, whether it is by having the measurably best DAC for the money, or having the "fanciest" one. Stuff like build quality counts, too, as do those nice convenience features.

[Modified by vwgtirob, 12:50 AM 1-26-2002]


[Modified by vwgtirob, 5:25 PM 1-26-2002]


----------



## JLJetta (Nov 24, 2001)

*Re: D/A Converters (vwgtirob)*

Heh... I SHOULD take your $2000.. but I won't.
You forgot some very obvious sources of audible differences in commercial DAQ's.
# of bit's ( program material, not DAC wise ).. such as 16 or 24bit decoding ( i.e. SACD, etc )
# of channel's, i.e. stereo versus 5.1 etc ( not the decoding, but the DAC of all the decoded channels mind you )
Sampling frequency
For example.. I could record a digital-music file of a 1Khz sinewave, recorded at a different sampling frequency.. which would obviously sound different thru a non-flexible DAC. 
And yes, I am talking about commercially available DAC's. I happen to use several National Instrument's at work that the ones you list will not be able to accurate reproduce many ( most? ) of the freq's etc. Perhaps you should be safer and limit it to only commerically available, consumer red/yellow book CD-standard DAC's. 
Other factors also include output configurations.. such as higher-voltage balanced XLR outputs. If you try to level match your little handheld to 9volts balanced.. it'll probably sound horrible ( let alone falling anywhere similar enough to require double blind listening to establish a difference ).
To a lesser degree, many portable's do not have flat frequency response, and hence, might be audibly different under the right conditions and test-signals. 
There are a few other's.. but I think that should sufficience is showing how if someone decided to take up your "bet".. they could have an easy time making money.
My point: do not be so absolutist without covering ALL the possible area's of audible difference. Otherwise, you sound just like Tom and as if you do not understand that there can be differences ( just not magical ones! ). If I had the time in my life, I'ld love to fly around the nation making a few hundred thousand on these imprecise "bets"... especially 'all amps sound the same" ignoring input sensitivity range, bandwidth issues, current capability, insufficienty dynamic range, etc.


----------



## vwgtirob (Aug 16, 2001)

*Re: D/A Converters (JLJetta)*

quote:[HR][/HR]Heh... I SHOULD take your $2000.. but I won't.
You forgot some very obvious sources of audible differences in commercial DAQ's.
# of bit's ( program material, not DAC wise ).. such as 16 or 24bit decoding ( i.e. SACD, etc )
# of channel's, i.e. stereo versus 5.1 etc ( not the decoding, but the DAC of all the decoded channels mind you )
Sampling frequency
For example.. I could record a digital-music file of a 1Khz sinewave, recorded at a different sampling frequency.. which would obviously sound different thru a non-flexible DAC. 
And yes, I am talking about commercially available DAC's. I happen to use several National Instrument's at work that the ones you list will not be able to accurate reproduce many ( most? ) of the freq's etc. Perhaps you should be safer and limit it to only commerically available, consumer red/yellow book CD-standard DAC's. 
[HR][/HR]​If I'm controlling the format of the digital source, none of the above matter one iota. Also, if it didn't do 20-20kHz, it'd fail the equalization test.
quote:[HR][/HR]Other factors also include output configurations.. such as higher-voltage balanced XLR outputs. If you try to level match your little handheld to 9volts balanced.. it'll probably sound horrible ( let alone falling anywhere similar enough to require double blind listening to establish a difference ).
[HR][/HR]​It's easy to match the handheld's output to the 9V balanced output: reduce the level of the balanced output.








quote:[HR][/HR]To a lesser degree, many portable's do not have flat frequency response, and hence, might be audibly different under the right conditions and test-signals. 
[HR][/HR]​I haven't tested -any- that didn't have a ruler-flat frequency response in the 20-20kHz range when any special processing was defeated. And even if it didn't, I'd EQ it out to be flat.
quote:[HR][/HR]There are a few other's.. but I think that should sufficience is showing how if someone decided to take up your "bet".. they could have an easy time making money.
My point: do not be so absolutist without covering ALL the possible area's of audible difference. Otherwise, you sound just like Tom and as if you do not understand that there can be differences ( just not magical ones! ). If I had the time in my life, I'ld love to fly around the nation making a few hundred thousand on these imprecise "bets"... especially 'all amps sound the same" ignoring input sensitivity range, bandwidth issues, current capability, insufficienty dynamic range, etc.[HR][/HR]​I think you'll find I covered a lot more than you think.







I -have- done this before.


----------



## nefilim (Nov 23, 2001)

*Re: D/A Converters (vwgtirob)*

Not quite







In my main system the differance in (soundstaging & slam most notably) sound between two of my DACs, an Assemblage 2.7 Platinum and a Sonic Frontiers SFD-MKII is easily distinguishable. 
Opamp vs tube output stage makes quite a differance, I think you should limit your conditions to one or the other


----------



## vwgtirob (Aug 16, 2001)

*Re: D/A Converters (nefilim)*

quote:[HR][/HR]Not quite







In my main system the differance in (soundstaging & slam most notably) sound between two of my DACs, an Assemblage 2.7 Platinum and a Sonic Frontiers SFD-MKII is easily distinguishable. 
Opamp vs tube output stage makes quite a differance, I think you should limit your conditions to one or the other







[HR][/HR]​Measure them. I bet the frequency response on the tube preamp DACs is far from flat (as have been every tubed DAC I've ever measured with one exception, and that one was accused of having a "sterile" sound).


----------



## JLJetta (Nov 24, 2001)

*Re: D/A Converters (vwgtirob)*

Ah yes. Just as I suspected.
You *intentionally* ignore area's of measurable audible differences.. and THEN claim there are *NO* audible differences. How uh, ethical.
You have learned from Tom, et all well. 
###
If I'm controlling the format of the digital source, none of the above matter one iota. Also, if it didn't do 20-20kHz, it'd fail the equalization test.
###
Yes, just as how that Yugo accelerates the same as the Ferrari when you control the throttle. You then turn around and say.. hey, this yugo is as fast as teh ferrari!
Sorry. You can not intentionally and blatantly ignore sources of audible differences, and then turn around and claim they do not exist. That is extremely unethical scientific behavior!
In any event, I would not allow YOU to control what *I* choose to use for source material. In any test for audible differences, I'ld design program material that I believe maximizes the chances.. not pick material which minimizes it! This is a common method to hide differences: the prevention of people to choose their OWN test material, and material which is highly selective in double blind, level matched tests.
The look on your face would have been priceless for my to bring my test-signals, and achieved a "statistically significant' Result of 20 out of 20 double blind trials... ;-) And on a simple 1Khz sinewave too!

###
It's easy to match the handheld's output to the 9V balanced output: reduce the level of the balanced output
###
Sorry. No can do. One does not castrate/hobble the performance of one particular DUT simply because other DUT's perform poorly. 
What you are proposing is to load up the ferrari with a thousand kilograms of lead to slow it down till the yugo is as fast. 
It is not *MY* fault that the DUT you wish to bring to the test can not accurately reproduce the test signals, and distorts/clips prematurely!!! 
###
I haven't tested -any- that didn't have a ruler-flat frequency response in the 20-20kHz range when any special processing was defeated. And even if it didn't, I'd EQ it out to be flat.
###
Ah, again.. the overconfidence. NOTHING is "ruler-flat" in the frequency response. NOTHING. 
The only issue is if it is flat enough to be audibly different. And yes, many cheap portable CD players are NOT flat enough to be inaudibly different. 
And what is with this equalization? YOu don't equalize something and then turn around and say it is inadibly different! 
If you have to equalize it.. then you have already *determined* it can be audibly different!
Really, you all schmuck's in the internet are *SO* predictable!
Oh, and it does not matter how *many* times you have done this.. if you are imprecise and ignore real world examples and use source-material that does not maximize test sensitivity.
*I* have enough experience that I looked at your so called "controls", and realized instantly how wide open they are. I'm telling you to be more CAREFUl with your absolute statements. Why? Because they have holes so wide that you can drive a semitruck thru them! If I wanted to, I could have accepted your challenge, ensured that an iron-clad contract was draw up with a lawyer.. and taken your money. Instead of pointing out the area's that you negligently FORGOT about when you issued your ultimative that there are no differences between DAC's. 
There are. Just none unexplanable.


----------



## JLJetta (Nov 24, 2001)

*Re: D/A Converters (vwgtirob)*

quote:[HR][/HR]
Measure them. I bet the frequency response on the tube preamp DACs is far from flat (as have been every tubed DAC I've ever measured with one exception, and that one was accused of having a "sterile" sound).[HR][/HR]​But you just stated: "I haven't tested -any- that didn't have a ruler-flat frequency response in the 20-20kHz range when any special processing was defeated. And even if it didn't, I'd EQ it out to be flat."


----------



## vwgtirob (Aug 16, 2001)

*Re: D/A Converters (JLJetta)*

quote:[HR][/HR]
Ah yes. Just as I suspected.
You *intentionally* ignore area's of measurable audible differences.. and THEN claim there are *NO* audible differences. How uh, ethical.
You have learned from Tom, et all well. 
[HR][/HR]​I intentionally ignore areas of measurable audible differences that don't denote any difference in QUALITY. If I wanted a more powerful signal, I can put an opamp buffer on the outputs. If I want a non-flat frequency response, I can put an EQ on the output and tweak it however I want.
###
If I'm controlling the format of the digital source, none of the above matter one iota. Also, if it didn't do 20-20kHz, it'd fail the equalization test.
###
quote:[HR][/HR]Yes, just as how that Yugo accelerates the same as the Ferrari when you control the throttle. You then turn around and say.. hey, this yugo is as fast as teh ferrari![HR][/HR]​You're free to control the content of the material, etc. The only thing I'm controlling is the quality of the digital input into the DAC (to isolate the DACs performance, rather than to test any particular transport, etc.)
quote:[HR][/HR]
Sorry. You can not intentionally and blatantly ignore sources of audible differences, and then turn around and claim they do not exist. That is extremely unethical scientific behavior!
[HR][/HR]​There's a difference between well-known differences between devices that don't have anything to do with sound quality, are easily eliminated, and cause qualitative changes in the perceived sound quality, versus differences not-so-easily measured that reflect a real improvement (or at least difference) in the sound quality.
quote:[HR][/HR]In any event, I would not allow YOU to control what *I* choose to use for source material. In any test for audible differences, I'ld design program material that I believe maximizes the chances.. not pick material which minimizes it! This is a common method to hide differences: the prevention of people to choose their OWN test material, and material which is highly selective in double blind, level matched tests.[HR][/HR]​I didn't mean to restrict your test material.
quote:[HR][/HR]The look on your face would have been priceless for my to bring my test-signals, and achieved a "statistically significant' Result of 20 out of 20 double blind trials... ;-) And on a simple 1Khz sinewave too![HR][/HR]​I doubt it. Even the THD of tube preamps are inaudibly low on test tones.

###
It's easy to match the handheld's output to the 9V balanced output: reduce the level of the balanced output
###
quote:[HR][/HR]Sorry. No can do. One does not castrate/hobble the performance of one particular DUT simply because other DUT's perform poorly. 
What you are proposing is to load up the ferrari with a thousand kilograms of lead to slow it down till the yugo is as fast. 
It is not *MY* fault that the DUT you wish to bring to the test can not accurately reproduce the test signals, and distorts/clips prematurely!!! [HR][/HR]​Bullsh!t. We're testing DACs, not cars, and the output voltage of the DAC is *HARDLY* analogous to the top speed or acceleration of a car. 0dB FS is 0dB FS, and whether a DAC decides to put out 0.707V at 0dB or 70.7V at 0dB is irrelevant. Besides, my preamp can more than handle either signal, so you get your hot signal all the way up to the input of my preamp, which, BTW, has XLR connectors and transformer balanced inputs, so you even get the benefit of a balanced line interconnect if you want.
###
I haven't tested -any- that didn't have a ruler-flat frequency response in the 20-20kHz range when any special processing was defeated. And even if it didn't, I'd EQ it out to be flat.
###
quote:[HR][/HR]Ah, again.. the overconfidence. NOTHING is "ruler-flat" in the frequency response. NOTHING. 
The only issue is if it is flat enough to be audibly different. And yes, many cheap portable CD players are NOT flat enough to be inaudibly different. [HR][/HR]​My ruler is only accurate to +/- 0.25dB in frequency response







Also, I had stated that the device needed to have a reasonably flat frequency response from 20-20kHz. This is a reasonable restriction, like having a 1/4mi drag race and requiring that all the cars be able to go 1/4mi.
quote:[HR][/HR]And what is with this equalization? YOu don't equalize something and then turn around and say it is inadibly different! 
If you have to equalize it.. then you have already *determined* it can be audibly different![HR][/HR]​That's only if you really want to test something so miraculously misconceived that it has a non-flat frequency response.
quote:[HR][/HR]Really, you all schmuck's in the internet are *SO* predictable!
Oh, and it does not matter how *many* times you have done this.. if you are imprecise and ignore real world examples and use source-material that does not maximize test sensitivity.
*I* have enough experience that I looked at your so called "controls", and realized instantly how wide open they are. I'm telling you to be more CAREFUl with your absolute statements. Why? Because they have holes so wide that you can drive a semitruck thru them! If I wanted to, I could have accepted your challenge, ensured that an iron-clad contract was draw up with a lawyer.. and taken your money. Instead of pointing out the area's that you negligently FORGOT about when you issued your ultimative that there are no differences between DAC's. 
There are. Just none unexplanable. 
[HR][/HR]​Now now, be nice.


----------



## vwgtirob (Aug 16, 2001)

*Re: D/A Converters (JLJetta)*

quote:[HR][/HR]
Measure them. I bet the frequency response on the tube preamp DACs is far from flat (as have been every tubed DAC I've ever measured with one exception, and that one was accused of having a "sterile" sound).
---
But you just stated: "I haven't tested -any- that didn't have a ruler-flat frequency response in the 20-20kHz range when any special processing was defeated. And even if it didn't, I'd EQ it out to be flat."














[HR][/HR]​In the first, I was talking about tubed DACs, and in the second I was talking about the few portable players (admittedly not exactly cheap ones, but not top-of-the-line either) I've tested.


----------



## MADBUG (Dec 14, 2000)

*Re: D/A Converters (vwgtirob)*

Interesting.


----------

