[jtwrace]

Is the one you picked up different than the JDS Labs version?

The case is a little different but sonically it should be the same.

[adydula]

I just got done doing a little experiment with the ODAC seeing how some folks seem to think they are having issue with the USB power supply in PCs etc...

I have heard that the USB power supply in some pcs are less than stellar, whatever that means.

Being an analytical guy I cut up some USB cables to allow for an ammeter and a voltmeter so I could see and monitor the current and voltage of what an ODAC would actually draw,

Well the results are:

ODAC draws 50.5 milliamps of current connected, doesnt matter if its connected to a amp or not. I tested this as well.

The voltage was 5.04 vdc, and after the ODAC was connected the voltage was 5.04 vdc.

The USB power supply in this old tired gateway desktop was not phased in the least with this minimal load.

The USB 2.0 spec is 100ma per unit up to 5 units for 500ma total.

The ODAC is not even close to this as a load.

So there ya go...now go get your super duper external power supply, but its NOT needed!!!

The truth is in the pudding!

Now anyone want some slightly cut up USB cables???

 

Alex

[wushuliu]

Please add an IMO to your statement. You are assuming that what you are analysing is the culprit; culprit for what you have not made clear - and you certainly did not make much effort to articulate the issues others have expressed with the dac in detail to at least some context with the exception of taking an underhanded stab at my previously shared efforts with power supply.

If you're going to go around making declarations at least lay out the argument in detail so we can all understand exactly what is being resolved, otherwise you are just preaching to choir.

If you don't like the fact that I recommend anyone run to build an external power supply because it sounds a hell of a lot better, too bad.
However I believe you stated earlier that doing so runs counter to the premise of the ODAC and with that I agree. I should never have gone anywhere near the thing. Just too much science for me. And way too much conversation. 
 

 

I just got done doing a little experiment with the ODAC seeing how some folks seem to think they are having issue with the USB power supply in PCs etc...

I have heard that the USB power supply in some pcs are less than stellar, whatever that means.

Being an analytical guy I cut up some USB cables to allow for an ammeter and a voltmeter so I could see and monitor the current and voltage of what an ODAC would actually draw,

Well the results are:

ODAC draws 50.5 milliamps of current connected, doesnt matter if its connected to a amp or not. I tested this as well.

The voltage was 5.04 vdc, and after the ODAC was connected the voltage was 5.04 vdc.

The USB power supply in this old tired gateway desktop was not phased in the least with this minimal load.

The USB 2.0 spec is 100ma per unit up to 5 units for 500ma total.

The ODAC is not even close to this as a load.

So there ya go...now go get your super duper external power supply, but its NOT needed!!!

The truth is in the pudding!

Now anyone want some slightly cut up USB cables???

 

Alex

[Speedskater]

I would say that Alex's post is pretty clear and factual and in keeping with the ODAC design philosophy and the sub-forums goal, so no "IMO statement" is required.

[doug s.]

I would say that Alex's post is pretty clear and factual and in keeping with the ODAC design philosophy and the sub-forums goal, so no "IMO statement" is required.

ya - everything except where he says:

"...So there ya go...now go get your super duper external power supply, but its NOT needed!!!..."
 

which is the most important part...  imo...   

the fact is, when it comes to power supplies, audible results have been known to occur in multiple instances, where measurements don't indicate why.  i know it has made differences in my experience, both w/my dac and w/my turntable.

doug s.

[Letitroll98]

I think both arguments are well presented so far.  I haven't heard the unit in either form so I couldn't comment directly.  However I do lean toward wushuliu's argument as I've invariably heard an improvement in DAC's when going to a beefier power supply, and I've never heard of any component anywhere not benefiting from better power supply regulation, unless we're talking battery power which actually is a better form of power supply regulation.  On the other hand adydula presents clear evidence that USB power in this case is more than sufficient.  Additionally the argument that the philosophy of the ODAC is a USB powered minimalist design carries a fair amount of weight on the C&C circle.  I'm not clear if adydula has listened to this DAC with with beefier power supplies or not, he mentions he has them, not sure if they've been hooked up here?  Anyway, the respectful exchange of ideas and information is a real benefit to all AC'ers, let's keep it that way.     

[wushuliu]

Oh you had to show up LIR, didn't you. I had a nice hamster wheel reply all set to go. I just want it noted that I backed away nicely from the topic earlier so that the thread could move on.

[JohnR]

On the other hand adydula presents clear evidence that USB power in this case is more than sufficient.

Um... I don't think it's a question of whether USB will supply enough current for an ODAC...

[doug s.]

Um... I don't think it's a question of whether USB will supply enough current for an ODAC...

+1.  which is why i posted that the "imo" is necessary for the most important part of alex's post - where he said upgraded external power supply isn't needed.   

doug s.

[adydula]

Wow!!!

Such excitement....on such a low current draw device.

Hey guys enough of the BS.

If I offended anyone, my apologies.

The short of my posts were just to point out that the ODAC draws 50 ma of current.

This is way within the capabilities of the USB 2.0 spec.

If you think that using a larger capacity power supply makes a real difference then hey spend your money and enjoy!

When people state that they hear HUGE differences by doing things like this I want to know if your really hearing differences that really matter.

If you tell others to go out and get a bigger supply and its not really needed when the USB supply will provide great sound and meet all the specs
that the designer has set....well I really wonder what your objectively hearing.

Its not that your a bad guy for indicating this....its my analytical engineering background that challenges these claims.

Heck it might be really true...but I honestly doubt it.

and yes I have a box of all kinds of DC wal-worts and a wonderful Lamba DC supply that can source mega-current if needed.

The fact remains that for the ODAC to operate and meet its design specs...you do not need anything more than a USB power supply can provide as
long as it meets the USB 2.0 specs. No IMO here.

The IMO part is hey try a nice big external supply and it gets even better....again I can respect this.

Happy Saturday!!
Time for a beer!!

All the best
Alex
 

[Letitroll98]

Um... I don't think it's a question of whether USB will supply enough current for an ODAC...

Well, that's why you're the engineer and I'm not.    Understanding that I'm among the great unwashed laymen, I thought that's what  adydula was pointing out, that you don't need anymore than USB power for the ODAC and anything more will have no effect on SQ.  As always on the web one has to point out that I'm asking a serious question and not making a sarcastic jab, but please expand, what is the question?

Oh, and adydula posted while I was writing this.  I think you guys have been pretty good about explaining your positions, which are polar opposites, while still being personally respectful of each other.  So no need for anyone to bow out or apologize.

[adydula]

Just some more food for thought...

When the O2 amp and the ODAC came out, and well before.... the designer went thru great pains to explain and tell the world what he was trying to do.

You can read all this on his blog.

It was not very long before many folks with all good intentions started to "make it better".
(yes this was mostly with the amp, not the dac).

Over on the DIY audio forum there are a ton of mod's for the amp, from a very well respected person, which I will not name here...
and most all if not all of his mods are prefaced by "it doesnt really add to the performance of the unit" but I had to muck with it....

The spirit of DIY is alive and well....and this is a good thing...

Its just the way it is, is pretty good too...

Alex

 

[adydula]

Letitroll98..

Thanks!!

Being an engineer....Is hard at times, it seems we trust nothing by facts, charts and graphs....

When I finally get lost in the music I know the design is right!!

All the best
Alex

[doug s.]

to reiterate, i will simply quote johnr:

"Um... I don't think it's a question of whether USB will supply enough current for an ODAC..."

i don't think anyone is disputing whether or not the usb will supply enough current.  it is correct that no "imo" is needed for this issue.  what is incorrect - imo - is that adequate current is all that affects the sonic end result.

i can tell you unequivocally that my art di/o dac was sonically improved w/a different p/s, even tho the stock unit supplied more than ample current.  i can tell you unequivocally that my oracle delphi turntable was sonically improved when i upgraded its motor to an origin-live motor, even tho the stock unit supplied more than ample current.  and then it was further improved when i upgraded the o-l's p/s to a hewlett-packard lab grade p/s, even tho the o-l's stock unit supplied more than ample current.

ymmv,

doug s.

[wushuliu]

@ ady - I believe you set up a strawman in the earlier post with the goal being to smack down my mentioning my super duper martin lawrence in a fat suit power supply:

the mentioning of people having technical issues with the usb power supply is unclear. I certainly made no such declaration here, only that I was not satisfied with the sound quality and have read others having similar experiences. I have only read one person specifically question whether the odac received enough power and that was rjm in his blog on diyaudio - and I don't think I mentioned that here either, so if there other specific mentions to usb power supply criticisms you are addressing it would be great if you clarified what those are.

Therefore measuring the current and voltage served no purpose. The ODAC performs within specs. Okay. Again, was this a question that was raised earlier? Has there been any disputation concerning whether it met specifications? I don't recall any such direct questions in this thread; if there are other previously mentioned forums or posts regarding this that I am not aware please share.

So the end result - a super duper big gulp power supply which by the way has only been mentioned/utilized by one person so far - is not needed. Great pains were made to emphasize that part and I have a problem seeing how you got there wihout implying that I (and others or just me?) found the stock odac to be potentially defective or ill-designed and receiving insufficient power, etc.

You're an analytical guy. I get that. Your position is clear. Get that too. But you make your argument and do your measurements based
on a statement or premise that was never made.

Just some more food for thought...

When the O2 amp and the ODAC came out, and well before.... the designer went thru great pains to explain and tell the world what he was trying to do.

You can read all this on his blog.

It was not very long before many folks with all good intentions started to "make it better".
(yes this was mostly with the amp, not the dac).

Over on the DIY audio forum there are a ton of mod's for the amp, from a very well respected person, which I will not name here...
and most all if not all of his mods are prefaced by "it doesnt really add to the performance of the unit" but I had to muck with it....

The spirit of DIY is alive and well....and this is a good thing...

Its just the way it is, is pretty good too...

Alex

 

[adydula]

Actually I have heard more than one person indicate they thought that had issue with the ODAC due to the USB power supplied by a PC.

So there are 2 areas of the ODAC and power that I have read about that an external supply might help, fix or whatever:

1. Various poppng or ticking or what one person indicated like hearting random fireworks going off during complex passages. (this particlar situation the person is very much in suspect of the design etc..).

2. The other issue being just replacing the supply with a 'better' supply will give your better sound?

In my particular experience with only (2) ODACS, I have not experienced ANY issues at all, zip, zero, nada....its just been all around excellent performance and with A/B testing indiscernable with my HRT MSii+ USB DAC.

The real point is to date this little $99 dac has performed admirably and provides many of us that cant or will not send thousand of dollars on a dac....stellar perfromance.

Alex

[JohnR]

As always on the web one has to point out that I'm asking a serious question and not making a sarcastic jab, but please expand, what is the question?

Power supplies are circuits, and like other circuits, can be fairly complex things. Other than the basic specification of voltage and maximum current, they have specs like noise, output impedance, and frequency response. That a supply provides enough current at the specified voltage is necessary, like saying, say, that an amplifier needs to provide 100 W into an 8 ohm load. But it's far from the whole story.

[adydula]

Dont know if anyone here is interested but you can actually explore the schematic of the ODAC here from a link on this site:

http://www.yoyodyneconsulting.ca/pages/ODAC.html

Its amazing on how the designer and this vendor is so open as to publish the schematics for all the world to see.

Not many vendors are willing to do this.

I copied these specs from this site:

•Frequency Response: +/- 0.1 dB (10 hz - 19 Khz 24/44)
 •THD+N 100 hz 0 dBFS: 0.0029%
 •THD+N 20 hz -1 dBFS: 0.003%
 •THD+N 10 Khz -1 dBFS: 0.003%
 •IMD CCIF 19/20 Khz -3 dBFS: 0.0011%
 •IMD SMPTE -1 dBFS: 0.0004%
•Noise A-Weighted dBu 24/44: --102.8 dBu
 •Dynamic Range: > 111 dB A-Weighted
 •Linearity Error -90 dBFS 24/44: 0.0 dB
 •Crosstalk 0 dBFS Line Out 100K: --93.5 dB
 •USB Jitter 11025 hz J-test 24/44: Excellent
 •Maximum Output Line Out 100K: 2.0 Vrms
 •Distortion: < 0.005%
 •PCB Dimensions: 49.0 x 58.0 mm

For such a dac to deliver this type of performance from USB power is, well amazing!

I would ask you which one of these specs is made "better" by using a "better" DC power supply?

All the best
Alex
 

[JohnR]

I would ask you which one of these specs is made "better" by using a "better" DC power supply?

I would ask you what you thought you were proving with your voltage and current measurement earlier?

[Letitroll98]

Power supplies are circuits, and like other circuits, can be fairly complex things. Other than the basic specification of voltage and maximum current, they have specs like noise, output impedance, and frequency response. That a supply provides enough current at the specified voltage is necessary, like saying, say, that an amplifier needs to provide 100 W into an 8 ohm load. But it's far from the whole story.

Thanks John.