Originally Posted by zzzmonster
Thank you for the reply. I have no doubts that the micro iDSD will be great and of course greater than the nano iDSD.
I will be direct and ask 2 questions:
1. Which is better in an environment with noisy mains - micro iDSD or mini iDSD not the nano iDSD?
2. Is iFi Audio planing to release another CD transport that is clocked slave to the mini iDSD? - Then I can offload my Audiolab :)
1. Run either on battery - why put up with bad mains? But if you run off USB power, then micro iDSD is better because of attention to power supply section.
2. Nope. But if you wish to use SPDIF via the CDT, then keep the AudioLab. You may get a Touchscreen PC with a disk drive or similar and play through USB? The GMT+ZeroJitter tries to make sonics as impervious to the USB connection as possible. So break-free of the audiophile need for synch'd locks etc...
GMT+Zero Jitter also kills SPDIF input Jitter via the coaxial.
All the tech notes largely illustrate that what we do inside makes what happens upstream and downstream far less mission critical.
Thorsten just asked us to put this up for you as it is hot off the AP2.
This sexy jitter test is done a la "Stereophile" (so you can compare with other mega buck DACs in the published articles to see how the micro iDSD stacks up).
Jitter tests style, 24Bit/48KHz:
It is the SPDIF input of the iDSD micro with a signal that had 50nS (50,000pS) of 400Hz squarewave jitter APPLIED (read: forced fed jitter that has been artificially created by the AP2's "Generate jitter" function).
We originally tried to generate this trace directly from the AP2 in loop-back. But at 50nS/400Hz square-wave jitter the AP2 could no longer lock onto the SPDIF signal. So we had to "hack" iDSD micro to disable ZJ!
- the top traces (Red+Green) is GMT+ZJ Jitter OFF. The micro iDSD is just like other DACs.
- the lower traces (Cyan+Yellow) are with GMT+ZJ enabled. It is basically identical to SPDIF in with NO jitter added and to the trace from USB. So you see, the iDSD micro does to jitter what Jason Bourne does to a trained assassin.
So no need to link the clock back. Any SPDIF source that is Bit-Perfect (not all CDP SPDIF outputs and really cheap DVD players are), will do. We take care to remove the jitter, be it via SPDIF or USB.
i. So what we did was to have AP2 simulate a SPDIF source so crappy, the AP2 itself could not lock onto the signal.
ii. The iDSD micro not only locked onto the signal but also killed all the 50,000pS jitter from the source.
iii. Top traces show that so much jitter produces noise with 400Hz (jitter frequency related) peaks every 400Hz and the noise is huge, we are talking around -40dB,it makes old Cassette tape distinctly noise-free.
So please go-ahead and make our day and put the micro iDSD in a "big, big rig."
As the Americans say, "bring it on."
Edited by iFi audio - 7/1/14 at 8:21am