Hi,

I am using since several years a Buffalo II but recently started to set up an additional Buffalo III for stereo and PCM/DSD playback.

The Buffalo III is conected via an XMOS based USB/I2S inteface to a dedicated audio PC running Windows Server 2012, foobar2000 and JPlay, nothing else. After some initial problems (Trident oscillations, firmware update, how to wire the inputs...)

I am just now listen music via headphones and are impressed

But I have some questions left for which I have not found any answers. May be someone can bring light into (my) the darknes.

1.
I was amazed that even with DSD the volume control worked! Since I have no datasheet of the ES9018 I am a little bit concerned that the chip converts DSD to PCM for volume control!? I hope that's not how they do it! Also i noticed some strange buzz like noise in the output signal when the DAC was feed with an DSD signal and the volume pot was turned. With PCM no problem.

Any information available how volume control for DSD is handled and generally how the signal path for DSD playback inside the ES9018 chip is?

2.
At the beginning I had an old firmware and had not realised that in the leonvb-Buffalo_III_DAC_Integration_Guide_V2.1.3 the settings of the DIP switches are described for the new firmware. This caused some problems due to wrong switch settings. But even with this I could hear PCM music from start on. Problem was that I got no LOCK with DSD. First I thought this could be a problem of the USB/I2S interface, but after checking the signals with a scope I found the expected signals (Clk, Data Left, Data Right). With the approved trial and error methode I figured out that the problem was caused by the DIP switch setting of the feature "listening Oversampling filter and reclocking", which was set to OFF. Setting the switch to ON fixed the problem.

This leads to the question if it is really so that it is not possible to bypass the oversampling/reclocker unit if also DSD playback needs to be supported?

3.
Has the ES9018 a hardware mute input (pin?) and if so is this pin accessible on the Buffalo III board?


Thank's for the help & Regards,
Peter