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RE: FOR JULI@ users: Removing output pulse trans could reveal more transparent sound!

There is a 74HC125 (the SMD 14 pin ic at the bottom near the PCI slot)driving the digital trans. The idea to add a tube buffer, in addition to the 74HC125, does not appear rational to me. To improve sound quality, I recommend the following two options:

1. Replace the SMD 74HC125 with a regular size 54HCxxx, a ceramic version which sound much better than regular 74HCxxx, not to mention SMD version. You can further improve SQ/noise by using small batteries to drive this IC, 3-7V only 15 ma.

2. If a tube buffer is to be used - remove the SMC 74HC125. Trace the origin of the SPDIF signal which should originate from the AKM 4xxx next to it. Tx should be fed to the tube buffer. I recall that Pin 16 is the Tx, download data to confirm this.

With regard to the two options, it matters whether you can provide a clear HT and Filament PS as noise is always an issue associated with tube circuit. The distance between the buffer and the signal source is also a concern, two long will do away the of idea of a good buffer. Too short, the tube can't practically be placed near the sound card or inside the case.

As a diyer, I prefer option 1. In this scenario a tube buffer is not necessarily better. The cost for Option 2 is too high: noise, heat, placement issue. Such discrepancies may outweight improvement to SQ.



Edits: 06/14/10

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