Received my Wadia i170 transport today.

Why spend a lot of money modding the iTransport? It is a perfectly good mechnism for delivering the data intact, just like the AirPort Express, Squeezebox, Sonos or Duet are. The money spent on mods is wasted as soon as the next best device comes out anyway, and you will never get your money back selling it on Audiogon. This is my advice, and I have been a professional modder for 8 years.

Instead, add a good quality reclocker with multiple outputs that will deliver really low jitter, can be used with future generations of devices, and has upgradability for higher sample-rates etc.. This will retain it's value and you can apply it to whatever you are using in the future.

Read this review for instance:
http://www.positive-feedback.com/Issue39/ramblings_computer.htm

Steve N.
Empirical Audio

Chris - a good transport will crush a stock iTransport. It uses the PCM270X part from TI to generate the S/PDIF output and reportedly has high jitter. This is not surprising since the AirPort Express uses the same part and has high jitter as well. I used to mod the crap out of the AE (called it the Off-Ramp WiFi), Superclock4, new power supply etc., and it still was not very good, so I discontinued this product. This chip is beyond help IMO.

Steve N.
Empirical Audio

Dazzdax - As a matter of fact, I am currently selling OEM USB interface modules to several companies, including Ultra-Fi (the iRoc DAC). The new version iRoc will debut at RMAF in Oct. Larry of Ultra-FI and I are tentatively talking about a collaboration too. Nothing serious yet. He does analog design and tubes really well and I do digital design really well and Larry does not have the usual giant ego that comes with most audio designers so there is potential there. I know Lavry and Peychev pretty well, but never met Keith Johnson, or at least I dont remember. Getting pretty old and the solder fumes are having their effect....

The problem with these types of collaborations is the business end of things. I have seen so many audio companies that have partnerships end-up in ruins or litigation etc. I'm too old to deal with that, and it's really no fun. I already have patent infringement on my cable products....

Steve N.
Empirical Audio

Oxia - I believe I can easily hear jitter in the 300psec range and so can you, depending on the spectra. (This is very difficult to measure accurately BTW). Here's why:

I had a mod for the AE some time ago, including power supply improvements, new S/PDIF output circuit and upgraded clock. It was called the Off-Ramp WiFi. The power and S/PDIF output mods improved the sound, but changing from the stock oscillator to a Superclock made the largest improvement. The only thing changing here is the clock and the jitter associated with the clock. The improvement in detail and image focus due to ONLY changing the clock was obvious in my system. Changing only the clock has no other effect than jitter.

Changes to the clock and other things that ONLY affect jitter is what leads me to the conclusion that jitter is the problem with the AE. I ultimately discontinued making the Off-Ramp WiFi because the jitter even with the Superclock, power supply and S/PDIF mods was still worse than even my USB converters. It is obviously audible in comparison.

Besides, with the AE, technically there is nothing else except jitter. With AE Toslink output, there is no RFI, no ground-loops, no other mechanisms. The data is bit-perfect.

The Toslink output from the AE can also be reclocked through a Pace-Car reclocker and this makes an even bigger improvement. One only has to listen for a few seconds to "get it".

Steve N.
Empirical Audio