by Kevin O'Brien on March 19, 2012

We wanted to let YFS readers know about our recent investigation into our M2Tech USB to SPDIF converter. Should you hook your digital source to your DAC via direct USB or should you use a USB to SPDIF converter in the chain and go digital COAX or digital XLR out to your DAC's input? Basically, we were wondering if we should be hooking our YFS HD-Ref-1 music server straight into our Minimax DAC Plus' USB input? Or should we continue to use our M2Tech EVO/ TeddyEVO Power Supply USB to SPDIF converter's BNC digital output and then hook that into the Minimax DAC Plus? Which scenario works and sounds better?

We figured enough folks would have an interest so we checked it out. We used the same set-up within the "IBM T43 vs. Theta Carmen II" review so you can check that out here. We ended up using a DELL Latitude D510 as our other computer source. It has essentially the same specs as the IBM T43 so we could keep things fair (we added a 150 GB HDD, 512 MB of RAM {1 GB total}, and it has a 1.87 GHz processor). Foobar 2000 was the digital player on both computers. We used the Silnote Audio Poseidon USB cable plugged into the M2Tech EVO from the IBM T43. We then used the Veloce 75 Ohm Black Cat Digital BNC cable to go from the M2Tech EVO to the Minimax DAC Plus. We used an ACR Reference Silver USB cable out of the DELL plugged directly into the same Minimax DAC Plus' USB input. Another important point to note is that the M2Tech EVO USB converter is essentially buried within the Minimax DAC Plus chassis, external PS aside. It's really more like the HiFace is inside the DAC chassis but you get our basic point. We definitely thought it would be an interesting shoot-out. We would be toggling between the two set-ups via the input switch on the Minimax DAC Plus.

Just a small note to the reader here first. We have compared the ACR Silver Reference USB to the Silnote Audio Poseidon USB and they are practically identical in sound quality! (neither cable is available today unfortunately) I wanted to let the readers know we are keeping the comparison as fair as possible. We feel here at YFS that the USB interface is the most preferable way to hook up your digital source to a DAC. Why do we say that? Look at the trouble we've had trying to get digital 24.192 signals through a COAX digital BNC cable to a DAC! None of our USB cables have had ANY trouble sending that signal to a DAC. You decide for yourself. (We think it's even better than firewire) Sorry to get sidetracked.

Now that you are familiar with the equipment and what we are trying to achieve, let's describe the results. We did an A-B comparison with both set-ups and we could not hear a difference! I know that different USB cables are involved in the test but we tested those out independently of this test and we feel they're both extremely similar. Both computers are essentially the same although the IBM has more RAM. We are using a legit digital COAX cable as well so we feel those are not the main factors in the test.

Adding the SPDIF converter and the BNC cable had no effect on sound quality. It neither added, nor subtracted from what was going on. The only difference by going DIRECTLY into the USB input was that we could now enjoy 24.192 and 24.176 digital files without any upsampling or downsampling. VERY SWEET!

What's the lesson here you say?

If you need to use a USB to SPDIF converter, don't be afraid of degrading your system's sound quality. Although there is a plus to using a straight USB digital signal into your DAC, it's not a deal breaker if you're happy with the resolution (24.96) you're getting out of your digital COAX cable!

Thanks for reading and enjoy!

 -KOB

 

Associated Equipment for this Review:

  • Eastern Electric Minimax DAC PLUS
  • YFS/ SCH Custom Speakers
  • YFS Custom Room Treatment
  • YFS Custom CA-60a Preamp and Custom 6L6 Tube Power Amp
  • YFS Custom Interconnects and Cables
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