Musiland Monitor 01 USD 24/192 USB to SPDIF

[jkeny]

I've modded my 01US starting here: M2TECH Hiface USB->SPDIF 24/192Khz asynch

[Pjotr]

I am listening to the IO-USD hooked to my M-Audio “Superdac” for a month now. This is by far the best I have heard so far with a DAC connected through USB (including the DacMagic). Although the E-MU sounds pretty good, it has still some uneasy edgy sound with longer listening. This is completely absent with the IO-USD – Superdac combo. This combo sounds very natural, open and with ease without any listening fatigue.

The Superdac is unfortunately not available/in production anymore for a long time. I have modded this thing in the past with a better external low noise stabilised PSU and better NS-LME op amps.

I see no use for a separate 5V for the IO-USD. My laptop has already a lo noise 5V on the USB port and the IO-USD is isolated from my audio set through the S/PDIF transformers, which are of pretty good quality. It are no cheap Chinese ones but Murata ones also used in pro gear (although made in China ).

[jkeny]

Hi Pjotr,
You can check how low noise PS on the laptop compares to your laptop running off batteries. I have found the Musiland DAC to repond well to my mods as I have detailed!

[Pjotr]

Hi Jkeny,

I have done so (it is an Asus EeePC 901 netbook) and I don’t notice any difference. The 5V has its own smps inside the EeePC. What amazes me is that, despite the standard Crystal S/PDIF receiver chip in the Superdac, measured jitter with a 11025 kHz test signal, is very low for a S/PDIF link: > -135 dB. But the Superdac has a dedicated input with a separate comparator and doesn’t use the comparator of the Crystal chip.

Also I don’t notice any difference when driving the IO-USB through ASIO or Direct Sound (WDM) with my JRMC music player. The drivers of the IO-USB work flawless with both. This was also a bit problematic with the E-MU drivers.

[jkeny]

Very good Pjotr

[Pjotr]

Maybe worth to mention is that the 5V of the Crystal S/PDIF receiver of the M-Audio Superdac is very sensitive to noise. With the standard wall wrath I get a whole bunch of 50 Hz (and its harmonics) related spurs in the jitter plot. These completely disappeared after I powered it with a good filtered and stabilised external PSU and did put some better (and bigger) Lo ESR Panasonic FC caps nearby the receiver chip.