[BornEvil]

Hi Guys,
 
A noob's 1st post, please be gentle  
 
Here is a little background/setup notes:
 
I run a pair of AD900X, which I like but do see upgrading @ Xmas.
 
I recently RMA'ed my Essence STX to my retailer, and to my surprise they sent me a brand new sealed replacement, I decided to sell it to cash in to dive a little deeper in dedicated DAC solution.
 
I have since bought a Maverick Audio D1+ with OPA627 OpAmp upgrades (and GE5670W tube which i don't use). I wanted the convenience of plugging my TV's Toslink (hence all my game consoles/satellite down-mixed) to the DAC/Amp combo and switching between sources.
 
Here is my problem I need advice on:
 
On the PC side of things, I have a ground loop problem (i think) when using the DAC's USB and Coaxial input from my on-board sound causing disgusting digital noise. This can be fixed by using optical out but that is reserved for the TV.
 
Another problem is it does this removed (not my video), says headphone/speaker is unplugged the plugged in often 'alt-Tab' me out of a game! This was always the issue, that is why I bought a STX in the first place and disable on-board sound in BIOS. Motherboard is an ASUS P8Z77-M Pro.
 
Also I am not satisfied with the SQ in music of the D1 compared to my previous Xonar STX setup. Would it be worth while to repurchase another Essence STX to use the RCA output running to the D1 using it's amp (and better opamp). This with give me the full 124dB SNR correct?
 
I still like the D1 to use with my TV.
 
Thanks for reading and any advice or enlightenment will be helpful.
 
Nick

 

[uncola]

If you're using usb to the d1+, then you can probably just disable your onboard sound in the bios.. then just work on fixing the ground loop isue

 

[BornEvil]

Thanks for the reply. That is true but I will still need a mic input.
 
I have multiple desktops and it does not have this problem at all, it just so happens that my main rig does . Spent last weekend taking apart multiply components to test and everything works except this particular motherboard's onboard sound
 
I am starting to think it is a motherboard problem, and bad power regulation. I notice I get interference with moving my USB mouse.
 
With the Essence STX before, getting clean power directly though molex, I don't recall any noise issues.

 

[uncola]

If it's a desktop pc, one cheap fix might be to install one of those pci-e usb cards and use a usb port off that

 

[Ari33]

.. and if uncolas suggestion doesn't work you could try using a USB isolator such as - http://hifimediy.com/index.php?route=product/product&path=60&product_id=122 

 

[BornEvil]

The USB DAC stage of the D1+, although decent, it is not as good as what I was used to with the STX. (Tested on another desktop with no noise)
 
TBH, i rather not spend extra money on parts unless it improves SQ. Hence I am leaning towards buying another Essence STX, then using the D1+ as a pure amp.
 
BTW, I am pretty sure it is the motherboard causing the noise problem. I really don't want to replace it as I don't wanna buy another Z77 motherboard (old tech) and I don't need a CPU upgrade. I have disabled the 3.5 ports so at least I no longer get popups disturbing my game.
 
I think the most cost effective solution for me is the buy a Optical to Coaxial Converter, to use with my TV. Then let the PC use the native Optical on the D1. Any thoughts about these converters?