[adydula]

phelix,
 
If its not crisp and clear something is not right....either your source material, your setup for bitpefect etc....I have used the O2 and compared with many other high dollar amps etc...its easy to get things mucked up in the settings and also using material that might not be up to par..
 
Tell us more about your reproduction chain etc...
 
Also note its not natural but neutral..ie no sound of its own like a straight wire with gain...garbage in garbage out....good in good out etc.
 
Alex

 

[kkl10]

Quote:

I've been searching for a nice little DAC and I'm interested in this ODAC. I've read that most USB powered DACs, and even DACs with their own power supplies, can benefit from an external cleaner power supply, instead of the dirty +5V sourced by most PCs VBus... Has anyone tried powering the ODAC with the Olimex USB isolator and a cleaner power supply? Or other cheap ADuM4160 based USB isolator? And there are devices like the AQVOX USB Low-Noise Linear Power Supply, Vaunix USB hub (Currawong says very good things of this with the ODAC), iFi iUSBPower... anyone tried these yet?

 
If anyone is interested in this question I raised some time ago...
 
I've acquired an ODAC, an Y USB cable and a 5V portable battery pack with 3Ah max output current through USB ports.
I've been comparing the power provided by the battery to the PC VBus and I can say that there is indeed an influence in sound.
I use electrical tape to cover the 5V pin in one of the A type leads of the USB cable, the one that provides both power and data flow.
With the "power-only" lead I compare both sources of power by switching between them.
The PC won't detect the ODAC with only the main lead connected to it, with the 5V pin taped, so I guess I succesfully disabled it's VBus power draw...
 
The difference in presentation I hear is very clear on my GMP and almost subtle on my Beyer which leads me to think that this is not going to show up in gear that lacks a certain level of transparency...
And even if it shows up it won't necessarily be an improvement, although in my case it so 'seems' to be...
 
With the battery power supply there's more apparent spacial resolution, soundstage gains definition and size, noticeably depht, and upper treble seems more "vivid" or at least clearer, the sound is also bit more transparent and laidback.
With the PC VBus feeding the ODAC there's a warmer presentation and everything sounds more forward, the finest spacial cues are lost. The soundstage is smaller, the bass is omnipresent and a bit bloomy which is more pleasent at times. Upper mids and treble are less clear...
 
The funny thing though, is that what made an even bigger difference was changing the interconnects, digital USB and analog RCA cables.

I know this is a controversial matter, I may be digging myself into an hole, but I can't deny what I hear.
Changing the interconnects between my components almost always imparts an influence in sound and the analog interconnects in particular sound very different between each other.
The difference between the first interconects I had and the ones that sound best is almost as much sonic improvement as switching from the PC line out to the ODAC... believe it or not.
 
I suspect this is because I was using cheapo 5$ cables and these may not be constructed in light of the norms they should follow... I don't know.
On my best sounding configuration I'm using a ~12 EUR Hama Y USB 1m cable bought from Amazon UK and a ~20 EUR Profigold PROA4200 0,5m RCA interconnect.
These cables are supposedly well constructed with twisted pairs wires, and proper shielding. They're the most expensive I have...
 
So there you go, this applies to me only, YMMV.

 

[scuttle]

Quote:

I now have an ODAC+O2 from Epiphany Acoustics and while it sounds kind of attractive, I don't find it that impressive and I even have my doubts about its objectivity. It's not particularly clear or crisp, it stays kind of in the background and in effect it's like there's layer on top which is slightly muffling. Soundstage is wide, depth is there, but it never really "shines", for one (e.g. strings), due to the muffling layer which sometimes seems to be an actual, distinguishable part of the sound rather than some abstract overall effect. Maybe these things will get into perspective eventually, people are also talking about a burn-in phase of such devices, but it's not what I expected a"natural" sound to be. I'm beginning to be skeptical about the "objective" criterion per se, maybe one has to give industry engineers more credit for making use of soundstage differently to create certain effects... Maybe it's a different story for any headphone (SennheiserHD 595) + source combo. I don't know, it's just a thought.

 
Have you tried tweaking the EQ? Veiling can be created by distortion products from high frequencies, a more "objective" amp will sometimes have a flatter fr and let more of these through, triggering distortion elsewhere in the range due to transducer imperfections. A quick solution for this is to EQ down the frequencies over 15kHz radically (like the curve of HiFiMan DAPs.) If you're out of your 20s you probably won't hear this upper range anyway.

 

[HamilcarBarca]

Quote:

Originally Posted by kkl10 /img/forum/go_quote.gif
 
I've acquired an ODAC, an Y USB cable and a 5V portable battery pack with 3Ah max output current through USB ports.
[...]
With the battery power supply there's more apparent spacial resolution, soundstage gains definition and size, noticeably depht, and upper treble seems more "vivid" or at least clearer, the sound is also bit more transparent and laidback

 
That's not how USB power problems affect the ODAC.

 

[kkl10]

I'm aware of the USB detriments.
This was just a particular case I wanted to share.
I didn't address common mode noise, nor ground loops here...

 

[ClieOS]

Quote:

 
That's not how USB power problems affect the ODAC.

One possibility might be that battery tends to response to current demand much faster and higher than most poorly designed USB port (especially if others USB devices are sharing the same power). Of course it could just as well be placebo.
 
I am quite interested in getting the iFi iUSB myself because I need to a high speed USB isolator, though will have to wait till March before I have the fund to buy it.

 

[kkl10]

That's one possibility.
I still haven't tried to assess if the ODAC actually benefits from more current availability than what my PC can provide, I think I could clarify this easily by untaping the 5V pin in the USB main lead and see if my battery pack still lights up...
 
I'm inclined to think that with my PC VBus the USB cable and the ODAC are subject higher levels of DC ripple, EMI, common mode noise, etc, resulting in higher Jitter...
The USB cable I'm using is pretty standard, I think, there's no separation between the data lines and the 5V power line so there might be some level of crosstalk, through the lenght of the cable, although it supposedly has twisted pair data lines...
Or the ODAC power filtering features are just not good enough...
 
The difference I hear with my GMP is clear, not subtle at all, pretty sure it's not placebo... I would be more inclined to think so if I only owned the Beyerdynamic where it's almost subtle.
 
I was interested in the iFi IUSB myself but it's just to expensive and my amp has a built-in ground lift so I think I can achieve similar result with cheaper alternatives. I'm interested in what it could do to the ODAC performance though...
 
Another thing in which I'm interested is how an "USB over Ethernet" server could influence an USB powered DAC performance, since standard Ethernet network connections are not subject to PC Master Clock Jitter, PC power supply quality and possibly also neither common noise nor ground loops issues, if an UTP cable is used, the same way USB is. I might give it a shot in the future.

 

[Phelix]

Alright, when making sure I had all extensions turned off, I might have accidentally ticked on bass extension. I removed it, and it sounds much more "open" now, not as muffled as I first thought. I also used my onboard audio output for a while, and though it sounds weaker and with more jittering than almost anything else, it also sounds very open and "bright". This also might have contributed to my first impression. Now the impression is very normal, "sound" and balanced.
 
Edit: It might also just be my ears getting used to it... Because although bass extension was on when last I looked, I remember clearly checking "turn off all enhancements" the first time, which makes it impossible to turn on bass extension... Something else I did some time inbetween was redoing all the plugs. Maybe it was that though I think it's unlikely because I did them thoroughly. I give up getting behind it and leave it at that.

 

[adydula]

There is no such thing as DC ripple....
 
There no benefit from more current availability.....
 
Alex

 

[tomb]

Quote:

There is no such thing as DC ripple....
 
There no benefit from more current availability.....
 
Alex

No, but there is such a thing as DC with ripple.  Perhaps it was only in his phrasing.

 
As for no benefit from more current availability, just curious - in what context are you referring?  I can think of many examples where more current availability is beneficial.  It's one reason we use large capacitors in certain places in a DAC circuit.

 

[adydula]

Hey Tom....
 
Yup....there is such a thing as DC with "AC" ripple.....that was my point....words are important....filter caps arent perfect.
 
As far as current availability the current that is drawn by a circuit is dependant on the load...the ODAC "draws" approx 50 ma of current..
 
The statement above the person is wondering " if the ODAC actually benefits from more current availability than what my PC can provide".
 
Its like if the power supply could source more than the device would draw this might make the ODAC "work" or "sound" better.....
 
If your pc had a 5vdc source capable of 10 amps current the ODAC still will only draw 50 ma or so...
 
The normal PC USB 2.0 power spec is a lot less...more like 500 ma total if implemented correctly...
 
The ODAC doesnt even come close to taxing the 5VDC in most pc's.....
 
Alex

 

[ProTofik]

From my experience, no matter if I connect my ODAC to battery powered laptop, my PC's USB3.0 or 2.0 port or to my Samsung Galaxy S3, it always sounds the same (which means very good). I also tried a couple different cables and can't hear any difference. 
 
Tested with O2 - Sennheiser HD600 and HD650

 

[tomb]

Quote:

Hey Tom....
 
Yup....there is such a thing as DC with "AC" ripple.....that was my point....words are important....filter caps arent perfect.
 
As far as current availability the current that is drawn by a circuit is dependant on the load...the ODAC "draws" approx 50 ma of current..
 
The statement above the person is wondering " if the ODAC actually benefits from more current availability than what my PC can provide".
 
Its like if the power supply could source more than the device would draw this might make the ODAC "work" or "sound" better.....
 
If your pc had a 5vdc source capable of 10 amps current the ODAC still will only draw 50 ma or so...
 
The normal PC USB 2.0 power spec is a lot less...more like 500 ma total if implemented correctly...
 
The ODAC doesnt even come close to taxing the 5VDC in most pc's.....
 
Alex

Well in that context, I agree with your assessment of extra current not being available.  That's why I asked in what context.

 
As for ripple, I would have to disagree and that's why I hate getting caught up in semantics or correcting someone else for that.  AC doesn't have ripple.  The very definition of "ripple" is a variation from perfect DC resulting from "a touch" of AC ... but whatever ...

 

[kkl10]

Ripple.
Shouldn't be to hard to understand what I was trying to convey with "DC ripple"...
 
adydula, I'm not in position to say what is the actual current draw from the ODAC, as I said before, I'm more inclined to think that the differences I heard were due to the cleaner battery power supply.
But, although I understand that a USB powered device will only draw as much as it needs, I find it hard to believe that the ODAC only draws 50 ma... how have you figured this out?
And is this value constant or it varies?
 
One bit of info about my battery pack that justifies my scepticism:
It's the Anker Astro3E model, this particular battery won't power anything that draws less than 80 ma... so my ODAC has to be drawing much more than 50...
 
My ODAC is a JDS Labs standalone unit with both 3,5 and RCA outputs... not sure if the power demands would be the same if it only had a 3,5mm output or if it were part of ODAC + O2 combo...
 
I ran USBView software to check what it would show up for the ODAC and here's what I got:
Note the darkish line. "0xFA" means 250
 
 
"
Device Descriptor:
bcdUSB:             0x0110
bDeviceClass:         0x00
bDeviceSubClass:      0x00
bDeviceProtocol:      0x00
bMaxPacketSize0:      0x08 (8)
idVendor:           0x1852
idProduct:          0x7022
bcdDevice:          0x0001
iManufacturer:        0x01
0x0409: "Binary Audio"
iProduct:             0x02
0x0409: "UAC1 DAC"
iSerialNumber:        0x00
bNumConfigurations:   0x01

ConnectionStatus: DeviceConnected
Current Config Value: 0x01
Device Bus Speed:     Full
Device Address:       0x01
Open Pipes:              2

Endpoint Descriptor:
bEndpointAddress:     0x81  IN
Transfer Type:   Interrupt
wMaxPacketSize:     0x0012 (18)
bInterval:            0x20

Endpoint Descriptor:
bEndpointAddress:     0x03  OUT
Transfer Type: Isochronous
wMaxPacketSize:     0x0246 (582)
wInterval:          0x0001
bSyncAddress:         0x00

Configuration Descriptor:
wTotalLength:       0x0151
bNumInterfaces:       0x04
bConfigurationValue:  0x01
iConfiguration:       0x00
bmAttributes:         0x80 (Bus Powered )
MaxPower:             0xFA (500 Ma)

Interface Descriptor:
bInterfaceNumber:     0x00
bAlternateSetting:    0x00
bNumEndpoints:        0x01
bInterfaceClass:      0x03 (HID)
bInterfaceSubClass:   0x00
bInterfaceProtocol:   0x00
iInterface:           0x00

HID Descriptor:
bcdHID:             0x0100
bCountryCode:         0x00
bNumDescriptors:      0x01
bDescriptorType:      0x22
wDescriptorLength:  0x003A

Endpoint Descriptor:
bEndpointAddress:     0x81  IN
Transfer Type:   Interrupt
wMaxPacketSize:     0x0012 (18)
bInterval:            0x20

Interface Descriptor:
bInterfaceNumber:     0x01
bAlternateSetting:    0x00
bNumEndpoints:        0x00
bInterfaceClass:      0x01 (Audio)
bInterfaceSubClass:   0x01 (Audio Control)
bInterfaceProtocol:   0x00
iInterface:           0x03
0x0409: "ODAC "

Audio Control Interface Header Descriptor:
bLength:              0x0A
bDescriptorType:      0x24
bDescriptorSubtype:   0x01
bcdADC:             0x0100
wTotalLength:       0x003E
bInCollection:        0x02
baInterfaceNr[1]:     0x02
baInterfaceNr[2]:     0x03

Audio Control Input Terminal Descriptor:
bLength:              0x0C
bDescriptorType:      0x24
bDescriptorSubtype:   0x02
bTerminalID:          0x05
wTerminalType:      0x0605 (S/PDIF interface)
bAssocTerminal:       0x00
bNrChannels:          0x02
wChannelConfig:     0x0003
iChannelNames:        0x00
iTerminal:            0x00

Audio Control Input Terminal Descriptor:
bLength:              0x0C
bDescriptorType:      0x24
bDescriptorSubtype:   0x02
bTerminalID:          0x09
wTerminalType:      0x0101 (USB streaming)
bAssocTerminal:       0x00
bNrChannels:          0x02
wChannelConfig:     0x0003
iChannelNames:        0x00
iTerminal:            0x00

Audio Control Output Terminal Descriptor:
bLength:              0x09
bDescriptorType:      0x24
bDescriptorSubtype:   0x03
bTerminalID:          0x03
wTerminalType:      0x0301 (Speaker)
bAssocTerminal:       0x00
bSoruceID:            0x10
iTerminal:            0x00

Audio Control Output Terminal Descriptor:
bLength:              0x09
bDescriptorType:      0x24
bDescriptorSubtype:   0x03
bTerminalID:          0x07
wTerminalType:      0x0101 (USB streaming)
bAssocTerminal:       0x00
bSoruceID:            0x05
iTerminal:            0x00

Audio Control Feature Unit Descriptor:
bLength:              0x0A
bDescriptorType:      0x24
bDescriptorSubtype:   0x06
bUnitID:              0x10
bSourceID:            0x09
bControlSize:         0x01
bmaControls[0]:
01
bmaControls[1]:
02
bmaControls[2]:
02
iFeature:             0x00

Interface Descriptor:
bInterfaceNumber:     0x02
bAlternateSetting:    0x00
bNumEndpoints:        0x00
bInterfaceClass:      0x01 (Audio)
bInterfaceSubClass:   0x02 (Audio Streaming)
bInterfaceProtocol:   0x00
iInterface:           0x00

Interface Descriptor:
bInterfaceNumber:     0x02
bAlternateSetting:    0x01
bNumEndpoints:        0x01
bInterfaceClass:      0x01 (Audio)
bInterfaceSubClass:   0x02 (Audio Streaming)
bInterfaceProtocol:   0x00
iInterface:           0x00

Audio Streaming Class Specific Interface Descriptor:
bLength:              0x07
bDescriptorType:      0x24
bDescriptorSubtype:   0x01
bTerminalLink:        0x07
bDelay:               0x00
wFormatTag:         0x0001 (PCM)

Audio Streaming Format Type Descriptor:
bLength:              0x1A
bDescriptorType:      0x24
bDescriptorSubtype:   0x02
bFormatType:          0x01
bNrChannels:          0x02
bSubframeSize:        0x02
bBitResolution:       0x10
bSamFreqType:         0x06
tSamFreq[1]:      0x001F40 (8000 Hz)
tSamFreq[2]:      0x003E80 (16000 Hz)
tSamFreq[3]:      0x007D00 (32000 Hz)
tSamFreq[4]:      0x00AC44 (44100 Hz)
tSamFreq[5]:      0x00BB80 (48000 Hz)
tSamFreq[6]:      0x017700 (96000 Hz)

Endpoint Descriptor:
bEndpointAddress:     0x82  IN
Transfer Type: Isochronous
wMaxPacketSize:     0x0184 (388)
wInterval:          0x0001
bSyncAddress:         0x00

Audio Streaming Class Specific Audio Data Endpoint Descriptor:
bLength:              0x07
bDescriptorType:      0x25
bDescriptorSubtype:   0x01
bmAttributes:         0x01
bLockDelayUnits:      0x02
wLockDelay:         0x0002

Interface Descriptor:
bInterfaceNumber:     0x02
bAlternateSetting:    0x02
bNumEndpoints:        0x01
bInterfaceClass:      0x01 (Audio)
bInterfaceSubClass:   0x02 (Audio Streaming)
bInterfaceProtocol:   0x00
iInterface:           0x00

Audio Streaming Class Specific Interface Descriptor:
bLength:              0x07
bDescriptorType:      0x24
bDescriptorSubtype:   0x01
bTerminalLink:        0x07
bDelay:               0x00
wFormatTag:         0x0001 (PCM)

Audio Streaming Format Type Descriptor:
bLength:              0x1A
bDescriptorType:      0x24
bDescriptorSubtype:   0x02
bFormatType:          0x01
bNrChannels:          0x02
bSubframeSize:        0x03
bBitResolution:       0x18
bSamFreqType:         0x06
tSamFreq[1]:      0x001F40 (8000 Hz)
tSamFreq[2]:      0x003E80 (16000 Hz)
tSamFreq[3]:      0x007D00 (32000 Hz)
tSamFreq[4]:      0x00AC44 (44100 Hz)
tSamFreq[5]:      0x00BB80 (48000 Hz)
tSamFreq[6]:      0x017700 (96000 Hz)

Endpoint Descriptor:
bEndpointAddress:     0x82  IN
Transfer Type: Isochronous
wMaxPacketSize:     0x0246 (582)
wInterval:          0x0001
bSyncAddress:         0x00

Audio Streaming Class Specific Audio Data Endpoint Descriptor:
bLength:              0x07
bDescriptorType:      0x25
bDescriptorSubtype:   0x01
bmAttributes:         0x01
bLockDelayUnits:      0x02
wLockDelay:         0x0002

Interface Descriptor:
bInterfaceNumber:     0x03
bAlternateSetting:    0x00
bNumEndpoints:        0x00
bInterfaceClass:      0x01 (Audio)
bInterfaceSubClass:   0x02 (Audio Streaming)
bInterfaceProtocol:   0x00
iInterface:           0x00

Interface Descriptor:
bInterfaceNumber:     0x03
bAlternateSetting:    0x01
bNumEndpoints:        0x01
bInterfaceClass:      0x01 (Audio)
bInterfaceSubClass:   0x02 (Audio Streaming)
bInterfaceProtocol:   0x00
iInterface:           0x00

Audio Streaming Class Specific Interface Descriptor:
bLength:              0x07
bDescriptorType:      0x24
bDescriptorSubtype:   0x01
bTerminalLink:        0x09
bDelay:               0x00
wFormatTag:         0x0001 (PCM)

Audio Streaming Format Type Descriptor:
bLength:              0x11
bDescriptorType:      0x24
bDescriptorSubtype:   0x02
bFormatType:          0x01
bNrChannels:          0x02
bSubframeSize:        0x02
bBitResolution:       0x10
bSamFreqType:         0x03
tSamFreq[1]:      0x00AC44 (44100 Hz)
tSamFreq[2]:      0x00BB80 (48000 Hz)
tSamFreq[3]:      0x017700 (96000 Hz)

Endpoint Descriptor:
bEndpointAddress:     0x03  OUT
Transfer Type: Isochronous
wMaxPacketSize:     0x0184 (388)
wInterval:          0x0001
bSyncAddress:         0x00

Audio Streaming Class Specific Audio Data Endpoint Descriptor:
bLength:              0x07
bDescriptorType:      0x25
bDescriptorSubtype:   0x01
bmAttributes:         0x01
bLockDelayUnits:      0x02
wLockDelay:         0x0002

Interface Descriptor:
bInterfaceNumber:     0x03
bAlternateSetting:    0x02
bNumEndpoints:        0x01
bInterfaceClass:      0x01 (Audio)
bInterfaceSubClass:   0x02 (Audio Streaming)
bInterfaceProtocol:   0x00
iInterface:           0x00

Audio Streaming Class Specific Interface Descriptor:
bLength:              0x07
bDescriptorType:      0x24
bDescriptorSubtype:   0x01
bTerminalLink:        0x09
bDelay:               0x00
wFormatTag:         0x0001 (PCM)

Audio Streaming Format Type Descriptor:
bLength:              0x11
bDescriptorType:      0x24
bDescriptorSubtype:   0x02
bFormatType:          0x01
bNrChannels:          0x02
bSubframeSize:        0x03
bBitResolution:       0x18
bSamFreqType:         0x03
tSamFreq[1]:      0x00AC44 (44100 Hz)
tSamFreq[2]:      0x00BB80 (48000 Hz)
tSamFreq[3]:      0x017700 (96000 Hz)

Endpoint Descriptor:
bEndpointAddress:     0x03  OUT
Transfer Type: Isochronous
wMaxPacketSize:     0x0246 (582)
wInterval:          0x0001
bSyncAddress:         0x00

Audio Streaming Class Specific Audio Data Endpoint Descriptor:
bLength:              0x07
bDescriptorType:      0x25
bDescriptorSubtype:   0x01
bmAttributes:         0x01
bLockDelayUnits:      0x02
wLockDelay:         0x0002

"

 

[adydula]

Hey Tom...
 
I agree....AC doesn't have ripple, that what I was trying to say....AC is all "ripple" (lol)....if you get what I mean...but DC from a rectifier half or full wave bridge supplied by the AC from a transformer will usually have some minute about of AC ripple ridding on the DC...and is measured in millivolts etc...but we know that....
 
The neat thing about the O2 amp (yes this is a ODAC thread is that it runs off of pure DC from batteries, and this means NO ripple...and all those AC power supply worts diappear....
 
KKL10: how do i know what the ODAC draws for current? Well I took a perfectly good cable and cut into in to put an ammeter in series with the +VDC liine and actually measured the current at quiescient and under operation.
 
I havent looked lately....but you can take a look at the USB specs at USB.ORG....but if I remember the USB spec is 500 ma total....and I think the USB 3.0 spec went up to 750ma.  Thats what the USB power "source" should be able to provide in needed.....in the ODAC case its not. The 500 ma "MaxPower" is what the USB source should be able to source. Even using MaxPower with current is mis-leading....power usually measured in "watts" not current.
 
As far as being "clean" DC from the PC USB's supply, I have not used an O'scope to actually see how much AC riipple of any other HF is actually on the VDC line. But I am am sure there is some in most cases.  That said the ODAC circuitry has a choke and filtering etc....and any noise on the USB VDC line from a PC .will have no real afffect on the sound quality.....unless bits are being dropped etc....if bits are being dropped its not usually due to a few millivolts of AC ripple.Also if your using a good USB cable with a ferrite bead this should help eliminate any induced gardage...but if stuff gets in the ODAC again its choke and filtering should help there....again its bits, not analog.
 
The ODAC in your integrated JDS O2/ODAC still is powered via the USB supply and the O2 amp gets its power from the half wave rectifier or batteries....its current draw will be different....I have not measured it myself but I think on nwavguy site its spec out...
 
All the best
Happy Ripple to All!
 
Alex