[pigmode]

Yup, egg/chicken unfortunately. 
 
I'd like to see comparisons between the OR4 and A2/w psu.

 

[bobeau]

Quote:

Originally Posted by leeperry /img/forum/go_quote.gif
 
Yeah, what we need is an affordable USB transport that outputs isolated I2S...when the market is flooded to death w/ coax, I can't seem to find any $500ish non-DIY/kludgy USB to I2S solution w/ serious clocking at all. The market needs to move on, I2S is the future. You can't isolate 480 MBit/s USB and S/PDIF is a highly flawed protocol(due to the slave mode clock recovery), so this strives for a more foolproof solution IMHO. Ah well, most DAC manufacturers go for a quick buck and don't care for I2S...so this will all end up being an egg/chicken situation I guess

 
John Kenny does.  Admittedly that falls in the DIY camp, although most seem to think pretty highly of the work he does.

EDIT:  Perhaps the issue is the lack of budget DACs with I2S?  I think it's just newer tech and will take some time for the market to mature.

 

[leeperry]

 

Perhaps the issue is the lack of budget DACs with I2S?  I think it's just newer tech and will take some time for the market to mature.

 
Well, m2tech ask $495 for a dumbed down DAC using a cheap opamp in its output stage off a SMPS wall wart...but yeah, it's got a I2S input: http://www.m2tech.biz/evo_dac.html
 
Its I2S input is very obviously a gimmick of the worst kind...I love how this company always tries to hide the forest behind the trees, the same way they kept calling the hiface "low jitter" but never ever bothered providing any measurement.
 
I2S is not new(circa 1986), S/PDIF is several decades old too...it's all going so sloooow =/

 

[Currawong]

 
Quote:

Clean USB out of PC

Is there any kind of consensus about how to get the cleanest signal possible over USB out of a PC? Some methods:

SOtM tX-USB PCI - So I undertand that this FILTERS out noise, but does it do anything for galvanic ISOLATION. Does it need to. There have been mixed results with this card because some say you have to manage IRQ in order for it to sound good. How does one ensure this device does not share IRQs with other devices.

USB Isolator - Like the Olimex provides galvanic isolation but does not filter. Does it need to. It can only pass audio up to 96. Can be bus powered or grid powered. Which is better? Does it matter.

AQVOX USB PSU - I understand that this will help provide clean power to a bus powered device like the Audiophellio2, but does not provide galvanic isolation. Is it necessary?

USB Hub - Like the Vaunix Brick USB Hub. Provies a solid power supply for Bus powered devices but does it provide galvanic isolation? Does it need to?

USB Cable w/ No Powerline - Does a USB cable with the powerline cut achieve the same thing as galvanic isolation. Bus powered devices would need their own grid power like the AQVOX. Is this enough?

Is any one of these items enough to clean the USB signal path or does it take a combination of devices? Which ones?

I have been trying out the Audiophilleo2 and can say that the sound quality of the unit is certainly effected by the signal it receives. Is the John Kenny JKMK3 any better at cleaning the signal? Does it provide galvanic isolation Does it filter out noise?
 
Any help would be greatly appreciated.

Without someone doing measurements, we can't know for sure. I don't know about the Olimex only passing audio up to 96k. USB Isolation has nothing to do with the USB signal. What is isolated is the power supply. I power my isolater using the PSU from the Audio-gd Digital Interface. I need to try other things though I think to see if I can hear any difference.
 
As for a USB cable with no power line, the computer wont recognise the device and think nothing is connected.
 

 

[drez]

I think the issue is that all of these USB isolators only work at full speed USB not high speed, so the limiting factor is the speed that the isolator will allow.
 
IMO I havent seen any indication why the green key is any different to other USB usb isolators apart from who made it.

 

[bobeau]

 
Quote:

 
I2S is not new(circa 1986), S/PDIF is several decades old too...it's all going so sloooow =/

Sorry, that was ambiguous - by newer tech I was speaking to usb convertors and the idea that computer as a source can actually be competitive with audiophile transports.  Before it always seemed to be giving up SQ for convenience... 
 
Thanks for the pointer on the M2Tech DAC, was not aware of that.  Even if it's junky as least it's a start, and the price is right
 

 

[Currawong]

Quote:

I think the issue is that all of these USB isolators only work at full speed USB not high speed, so the limiting factor is the speed that the isolator will allow.
 
IMO I havent seen any indication why the green key is any different to other USB usb isolators apart from who made it.

 
It's not an issue with USB 2.0, which the Isolator is. USB type labelling leaves much to be desired, as it can be confusing. From Wikipedia:
 
 
Quote:

The original USB 1.0 specification, which was introduced in January 1996, defined data transfer rates of 1.5 Mbit/s "Low Speed" and 12 Mbit/s "Full Speed".^[3] The first widely used version of USB was 1.1, which was released in September 1998. The 12 Mbit/s data rate was intended for higher-speed devices such as disk drives, and the lower 1.5 Mbit/s rate for low data rate devices such as joysticks.^[4]

 
USB 2.0 is labelled on devices as "USB Hi-Speed" and easily has enough bandwidth for 192 kbit/sec audio.
 
Good point though about checking the capabilities of devices, however it's mainly an issue with S/PDIF and AES converters, as not all have the necessary clocks to handle the different audio rates (44.1, 48 and multiples of those).
 

 

[DaveBSC]

Quote:

I think the issue is that all of these USB isolators only work at full speed USB not high speed, so the limiting factor is the speed that the isolator will allow.
 
IMO I havent seen any indication why the green key is any different to other USB usb isolators apart from who made it.

According to Vaunix, the Lab Brick does basically everything possible will still allowing for maximum USB 2.0 speed. Any more filtering, and you lose 480mbit capability. My hunch is that the Lab Brick powered by something like a Hynes linear PS (or a battery supply) in place of the wall wart is probably best, though I'd definitely like to see a comparison vs. the SoTM card and some of the other devices.
 
You can cut the powerline from the source, but that 5V still has to be supplied from somewhere.

 

[AppleheadMay]

Where would one look for that Hynes linear PS? And what type exactly would be needed for the Vaunix?

 

[leeperry]

 

I havent seen any indication why the green key is any different to other USB usb isolators apart from who made it.

 
As usual, implementation is everything. I compared several dongles on the Firestone Bravo(+Supplier DPS) and the Olimex sounded the best to my ears...but it wasn't either designed or specifically meant to be used on audio gear. This is the first commercial audiophile USB Isolator I'm seeing.
 

Good point though about checking the capabilities of devices, however it's mainly an issue with S/PDIF and AES converters, as not all have the necessary clocks to handle the different audio rates (44.1, 48 and multiples of those).

 
I'm not a math geek, but I believe you can't transport more than 24/96 over 12MBit/s...that's how I understood it anyway.

 

[DaveBSC]

Quote:

Where would one look for that Hynes linear PS? And what type exactly would be needed for the Vaunix?

You order them from Paul's website. Bolder Cables also makes linear supplies, but they are more expensive. According to the Lab Brick website, the AC adapter is 12V, 24W. Unless I'm mistaken, that works out to 2A, which both the Hynes and Bolder supplies can do at 12V without any problem.
 

 

[AppleheadMay]

I found his site, thanks.
I see he has a 12V model SR1-12 Supply, but it's listed at 0.6 A so I guess that won't work?
I checked the wallwart thing that came with it and it has 0.5A input and 2A output.
Those US plugs are indeed dangerous, managed to elctrocute myself while plugging it back in.  

 

[DaveBSC]

Quote:

I found his site, thanks.
I see he has a 12V model SR1-12 Supply, but it's listed at 0.6 A so I guess that won't work?

Paul makes all kinds of stuff that he doesn't list on his site, I think you'd just have to ask for a 2A+ supply.
 

 

[drez]

Quote:

As usual, implementation is everything. I compared several dongles on the Firestone Bravo(+Supplier DPS) and the Olimex sounded the best to my ears...but it wasn't either designed or specifically meant to be used on audio gear. This is the first commercial audiophile USB Isolator I'm seeing.
 

I'll look forward to your review 

 Anyway I can't get my Hiface to work with the OMLIEX isolator, not sure what to make with that.

 

[bcwang]

After being away from this thread for a while, I just caught up.  I wonder if Audioexcels has a faulty Audiophilleo.  It sounds like it got slaughtered by an OR4 in a test, but other posts he also seem to indicate it performs worse than a hiface in soundstage and close to other spdif sources in overall sound.  Pardon if I got that summary wrong, but that was my impression after reading these posts in reverse once.
 
What would have been good is if Audioexcels takes a known good Audiophilleo that is broken in, powered with an AQVox (since we know the AP is sensitive to power supply), and directly connected it to the DAC.  This is pretty much as good as the AP will sound short of the battery pack mod as far as I know.  It wasn't clarified how the AP was powered in the comparison setup, as it could have been a highly noisy usb power while the OR4 had the advantage of it's own power supplies. 
 
I myself use an AP2 with AQVox setup and it significantly outperforms other spdif output sources including various computer sound cards, motherboard spdif outputs, dvd/cd/blu-ray player digital outputs that I've tried.  The fact that Audioexcels finds the improvement minor to none makes me question if he indeed has a defective unit or if the AQVox supply makes so much difference that it is the missing link in his setup.  If the AQVox was also plugged into something that cleaned up the AC power that may help even more.
 
Just my thoughts!