[skeptic]

   
Interesting, so the ADuM3160 in the Doodlebug actually keeps the grounds of USB in and USB out separate?

 
Yup.  Although I think I need to amend my prior comment, following further reading, to acknowledge that there is some debate over the pros and cons of this approach.  On the BH boards, it looks like Swenson thinks the adum chips (in particular) reduce noise but add some jitter.  http://bottlehead.com/smf/index.php?topic=4086.msg50790;topicseen#msg50790  Although, he still suggests that properly implemented ground plane isolation coupled with signal isolators is the best overall approach.  http://www.audiostream.com/content/qa-john-swenson-part-2-are-bits-just-bits  
 
Adum vs. GMR chips aside, it seems like the guys who build up doodlebug beta boards are all pretty happy with them.  Since the doodlebug is so cheap, and so is the wyrd, I may just have to try both when time permits.

 

[estreeter]

I'll stick with the iUSBPower, even if the iFi cable does annoy the hell out of me. Not sure who sits down to design a cable this heavy when they know it's designed to be plugged into a lightweight component like the iUSBPower. 
 

 

[Sorrodje]

  blablablabla
 
 

 
 
Do not take me for an idiot please

. I know that.
 
What I want is to understand what Purrin & those friends said when they talk about "sabre" sound. I have currently an Odac and I had the tiny hifimediy I loaned you a few time ago.  Indeed I forgot that Odac is based on a sabre chip.

 
@purrin : Are ODac & hifimediy representative of other more expensive Sabre DAC you dislike ?
 
I received yesterday a Beresford Bushmaster. Cheap but very very good if I trust my ears. The Embedded headphone amp seems weak but I'll try to use it soon with the Sonett or the 02

 

[Jason Stoddard]

   
Interesting, so the ADuM3160 in the Doodlebug actually keeps the grounds of USB in and USB out separate?

 
Kinda. At the cost of 480Mbps. Max 12Mbps, so not full-speed USB2 compatible. Which is why we didn't use it.
 
There is no effective galvanic isolation for full-speed USB2 data rates. Funny how the buzzwords change, huh?

 

[purrin]

 
 
@purrin : Are ODac & hifimediy representative of other more expensive Sabre DAC you dislike ?

 
Yes more or less. I think I wrote a blurb a few posts back on the SABRE sound. SABRE is the opposite of say something like your Octave.

 

[Sorrodje]

Interesting... 

 
 
The octave is OFF and unplugged right now. Currently using the Bushmaster.

 

[aive]

  Hugo comparison to Geek Wave. (I have not heard the Wave): http://www.head-fi.org/t/713829/light-harmonic-geek-wave/660#post_10871785.
 
BTW a few updates to page one. Ranked most of the newer DACs after some discussion with the ninjas. Note AGD M7 USB firmware update makes M7 with stock USB (without fancy converter) now highly worth considering.

 
Thanks for the heads up, didn't realise there was new firmware for the M7! Noticing bass in Daft Punk Giorgio is slightly more resolving (a SMIDGE more if so)... but not sure, could be my SuSy Dynahi contributing to the change too...

 

[Chris J]

Interesting... 


The octave is OFF and unplugged right now. Currently using the Bushmaster. :blink:

The Bushmaster Mk II?
Yes, it's an excellent DAC for the money.
I believe it uses a Wolfson DAC.

 

[Sorrodje]

MkII indeed. I'm very impressed by the sound produced by this DAC. But it can be a "new toy" effect. Octave will stay off for a few days I guess.

 

[Tony1110]

I'll stick with the iUSBPower, even if the iFi cable does annoy the hell out of me. Not sure who sits down to design a cable this heavy when they know it's designed to be plugged into a lightweight component like the iUSBPower. 

A lot if cable manufacturers will make you a twin-headed USB cable if you ask them. Cheaper too. I recommend the one made by Matthew at FORZA Audioworks.

 

[azteca x]

   
Kinda. At the cost of 480Mbps. Max 12Mbps, so not full-speed USB2 compatible. Which is why we didn't use it.
 
There is no effective galvanic isolation for full-speed USB2 data rates. Funny how the buzzwords change, huh?

Well that's a damn shame. I hope we get there.

 

[StefanJK]

   
Kinda. At the cost of 480Mbps. Max 12Mbps, so not full-speed USB2 compatible. Which is why we didn't use it.
 
There is no effective galvanic isolation for full-speed USB2 data rates. Funny how the buzzwords change, huh?

Why do we need more than 12Mbps?  Even 24/192 is below that if I'm not confused (always possible), at 1.125 Mbps. 

 

[SoupRKnowva]

Why do we need more than 12Mbps?  Even 24/192 is below that if I'm not confused (always possible), at 1.125 Mbps. 

Not quite, 24 bits per sample times 192000 samples per second times two channels is already over 9mbps, not to mention overhead. And it's not like usb always transfers at max bitrate.

 

[castleofargh]

 

   
Kinda. At the cost of 480Mbps. Max 12Mbps, so not full-speed USB2 compatible. Which is why we didn't use it.
 
There is no effective galvanic isolation for full-speed USB2 data rates. Funny how the buzzwords change, huh?

Why do we need more than 12Mbps?  Even 24/192 is below that if I'm not confused (always possible), at 1.125 Mbps. 

 
 

 

Why do we need more than 12Mbps?  Even 24/192 is below that if I'm not confused (always possible), at 1.125 Mbps. 

Not quite, 24 bits per sample times 192000 samples per second times two channels is already over 9mbps, not to mention overhead. And it's not like usb always transfers at max bitrate.

you're saying the same thing, one with bytes the other with bits

 

[purrin]

My question is - are the grounds truly isolated? In the US for 120V, there is hot, neutral and ground on the AC outlet. Even if the ground (outlet) of the devices are isolated or not used, the neutral is still tied to the neutral tie block to where the ground is also tied (just that ground path has less resistance).
 
So yes, the ground is broken at the USB-USB chip. But what about the other way around at the power supply / outlet of the two devices?
 
Are we isolating something that was never isolated anyways at the outlet?