Thanks for spending the time it took to write and post all that
(Edit....Just realised that you posted that in October 2007!! I never did get around to reading pages 60 to 70 of this thread!)
A clock mod onto this sound card is one of the things I've not tried.
How did you know which way around to connect to the two wires to the two holes where the Crystal was? And did you remove the 22pF's and the 1M Ohms?
I think that companies like that one prey on vulnerable people who have enough money and no technical knowledge. Parts connection are asking €430 for that http://www.newclassd.com/index.php?page=36
which is a huge rip off considering that's something like a £5 board with perhaps £10 of parts on it that are doing nothing particularly special. There are many clock modules that are much less expensive and offer squarer wave forms than that one appears to offer, or sine wave like the one I and a RF engineer friend designed in the 1990's . People felt ours sounded better than the square wave form, but eventually I seemed to find that just giving the digital filter chip and good power feed meant I could no longer hear the difference between the different clocks. Maybe the difference was never more than the quality of the regulation and decoupling that the various clock boards came with!?
That long lead with the one you're using likely smears the wave form so it no longer has sharp transitions, and may be ringing a bit. Recently, I and a friend, using his state of the art professional DSD recording studio and mastering suite, compared leads from the DSD recorder master clock output, maybe a dozen different clock leads of all expenses, including the Siltech Crystal, and they all made a different change to the sound. Shorter was better.
You can get A LOT MORE from that sound card that you currently are. I own and tried those NX Black gates, they are boomy, smeared and blurry. That double cap on the left of the DAC chip is to AC couple the DAC chip ground to the ground plane. It's of critical importance to the speed and dynamics of the sound. It needs a polystyrene 10n or so across the 10uF. I stuck with the original 10uF value in case there was a time constant or filter or anything that required that value. For the caps on the right of the DAC chip, I went up to 2460uF in the form of three parallel 820uF caps, more caps lead to more and stronger bass volume. I used the Nichicon Polymer caps as they were the cleanest and fastest sounding, far better than black gates, all be it with less bass but a cleaner and much more informative bass which we preferred. Favourite Op-Amps are the metal can TO-99, not plastic, and single, NOT DUAL, LME49710HA. Some people are liking the newish LME49990 surface mount chips now, but I've not tried those.
That capacitor you've replace with those two large Black Gates is the muting time delay for the switch on de-thump control. Nothing at all to do the pre or post regulation power supply, it doesn't decouple anything in the audio path. It's a common and astonishing mistake that people throughout this thread have been making; instead of finding out what the parts on the board do, they just change the largest capacitor!!!!
Here's my X-Meridian:, I've not changed it much, or at all, since those posts about 2 years ago.
Spread over a couple of pages:
I've measured it's sine wave output and found that it's not even at all frequencies. I'd like to re-do the output stage but off the board, on it's own board, with Vishay resistors and polystyrene capacitors. Or I maybe moving toward a Sabre ESS DAC and am considering running I²S to it from the X-Meridians CMedia DSP. I think it's just three or four wires. Take off the AK4396 and take those wires from that point, over to the new DAC on it's own board with it's own far better PSU. That then preserves the cross feed for my headphones.
I ran the headphone amplifier from the ± 8 Volt X-Meridian rails, soldering take off wires just after it's regulators and earth wires to the solder side of the line output sockets, then instead, I changed the headphone supply to my own PSU and wow what a big improvement! The supply rails on that sound card are VERY noisy! Hence I want to feed the output stage and DAC chip separately too.
If you change your sound card to be like mine you totally won't believe your ears when you hear it! And you may find your eyes water a bit!
And the cost in parts? Maybe £61. MUCH less that your clock module and FAR better. Edited by Ian AS - 2/22/13 at 6:36am