[bhobba]

There is an argument raging on Steronet out here in Aus about Jitter and async.  I believe async certainly helps Jitter but may not always eliminate it - it may still be possible for a little to creep through.  I believe Steve does stuff like double buffering to really stop it dead but without measures like that will async always eliminate it - in other words will even the most basic async device eliminate jitter?

That is certainly not my experience with devices like the async in the WFS2 being totally blown away by the Off-Ramp - or is something else other than Jitter going on?

Thanks
Bill 

[wilsynet]

I had an Off Ramp 3 with BPT battery supply about 2 years ago, and it was stellar.  My memory is imperfect, but my recollection is that it easily outclasses both the M2Tech Hiface and the Audiophilleo 2 which I've had in my system since then.

I imagine the Off Ramp 5 is even better.

[audioengr]

Bill - Async does enable the USB interface to isolate the jitter of the input signal from the jitter of the local oscillator.  Neither will have zero jitter.

I believe the reason that different cables and USB interfaces can sound different with async USB is mainly due to common-mode noise over USB.  RFI may also be a factor, depending on the design and shielding.

I proved this to myself by making a common-mode filter for USB and disconnecting the 5V wire in the cable.  The improvement in SQ was immediate and noticable.

The signals of USB are differential digital, similar to balanced in analog.  The ground wire is only there to insure that the DC potential of the grounds of the two systems (computer and USB interface) are similar.  Different USB receivers will have different levels of common-mode noise rejection.

The reason that some USB interfaces dont sound as good as the Off-Ramp is that the local clocks have higher jitter, or jitter spectrums that are more undesirable for audio.  The edge-rates of the S/PDIF output signals on USB converters also impact jitter, as well as any duty-cycle distortion caused by the master clock.

Steve N.

[Audioexcels]

Jitter will always exist.  I'm pretty positive the Audiophilleo has recorded the lowest jitter out of these asynch devices, but we know how it sounds vs. the Off-Ramps...I don't understand these people paying $400 or whatever it is to upgrade their Audiophilleos with the battery supply when for $200 more you get an Off-Ramp 5, but whatever.  I personally think the low jitter clocks Steve mentions is helpful, but I believe the way things are put together/designed/etc. is what it is all about.  Steve obviously have "overbuilt" designs vs. anything else out there.  This doesn't always equate to better sound, but it generally does particularly when done/implemented correctly as Steve has done.  I'd put my money on the design, a little on the clocks, and that's where the Off-Ramp stands out on its own as the most superior converter available.  Now if Steve's overbuilt Off-Ramps had a poorer implementation than even super cheap Hiface designs, then it would not sound as good...I'm just 99% about implementation including "good enough" parts, and 1% about use of super fancy parts...And how much that 1% can be heard is up for the listener to decide, then tweak, then tweak, then...and you get the idea;).

Steve is just the digital king of USB conversion, IMHO.  I do believe all the asynch devices out there do offer a certain "sound", and one may prefer one over the Off-Ramp, even the cheapest of available options, but as I have mentioned and have heard, if the Off-Ramp could shame the Audiophilleo so badly, it must be able to shame anything else out there.  This said, if another said they felt otherwise, and their Halide or U3, etc. was better, I would never say they are wrong.  It's all personal experience, mine again, being, the Off-Ramp is just extraordinarily well implemented/designed, happens to use fancy  crazy clocks, but it's the designer of the product, IMHO, that is bringing the sound...not the fancy clocks (though they do help with that 1%)...