My router is 3ft away but it wasn't an issue before unless I didn't notice it, the ticking is hard to hear. I did move to a new house but all my equipment is the same.

Occasionally my amp will pick up a weird ticking noise with no input. It doesn't change with volume and if I hover my hand over the tube, it goes away... I haven't been able to figure out what is causing it.

Its been a few years since I built my o2 and wanted something new/different. I don't know if I have bad hearing but its not that microphonic. When you first turn it on there is a high pitch ring but it goes away after about 10 seconds. I have to tap on the case real hard to get it to ring, with...

Taken from the blog . If your line voltage is below 117 VAC or 235 VAC, and/or you plan to drive difficult low impedance headpones (i.e. HiFiMan planars), I would suggest a 14+ VAC transformer at 400+ mA. The best Mouser transformers are the WAU16-400, 412-218054 or WAU16-1000 CUI. But those...

Turn off flexbass and have the receiver handle bass management, its probably disabled.

I never built anything like the o2 but I have done some soldering. It really wasn't that difficult and there is tons of information on how to build and test it. If you're confident in your soldering abilities then I say go for it!

objective2

Why do you need the schematic? Buy the PCB and case at jdslab. The PCB has a silkscreen of all the components so you just drop the right part in there and solder. I use my o2 as a desktop amp with no batteries, just a wall adapter.

  I just realized that the Front lineout on the Xonar DG is also the headphone port which is amplified. The DX and D1 don't have a headphone amplifier?

Does the Xonar DX (or any other high quality sound card) support Dolby Headphone through the line output so it can be used with an amp? I'm thinking about upgrading my Xonar DG which supports this feature. 

I think the sound card had an audible hiss which why I got the Fiio. I would get a USB DAC if there was a way to use Dolby Headphone.

I use Dolby Headphone for gaming and movie watching which is why I need toslink.

I'd like to try soldering SMD components and the only DAC with a Toslink input that I've come across is the y1 from AMB.   Are there any other DIY DACs around $100?

If you play them loud enough in a quiet room, they can be heard.

I have no idea. I would guess a dedicated optical adapter is best but its all digital till it gets to your Fiio. Most likely there would be no audible difference.