upstateguy
Headphoneus Supremus
- Joined
- Dec 20, 2004
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Quote:
USG,
I did a little experiment at work yesterday comparing optical out on a macbook and imac to the modded hiface feeding a headroom ultra micro dac (it has undefeatable upsampling). I also compared the optical out to the modded hiface with a 15dB attenuator. I was using my SE530's, an inexpensive coax cable from esoteric usa and an optical cable from lifatech. The DAC has a manual switch that I can flip to optical or coax input.
The setup I used included two computers with one computer feeding optical and the other feeding the Hiface and both coax and optical inputs of the DAC were simultaneously being fed signal. Lest I be accused of not being thorough, I switched computers and checked my results and they were similar. I had to sync iTunes/Pure music between the 2 computers and then changed inputs on the DAC as the tracks were playing. This was no means a blind test.
First off, I did not hear any volume differences between inputs in this setup. The optical out of the Mac's and modded hiface were similar sounding; however it was clear that the presentation with the hiface was more organic and had a bit more dimensionality. When I added the attenuator the sound improved a great deal. The presentation became 3 dimensional and the tonality of the instruments was much better than without the att. or the optical input. The reverberation within the recording venue was revealed more clearly. In addition there was a better lower end presentation that grounded the music and provided a more solid and satisfying experience. I was listening to a redbook recording of Carmignola Vivaldi late violin concertos.
Even using this modest setup consisting of the ultra micro stack with SE530's, I was able to detect these differences.
What I took away from this is that the attenuator helps as John has suggested by reducing reflections. I have now tried 2 upsampling DACs and I can hear differences with the modded hiface feeding the DAC's compared at least with optical out. The sound improves greatly by including the attenuator in the HIface setup!!!!! In my experience, the benefits of feeding good (presumably low jitter) digital signal to an upsampling DAC can be heard but it becomes extremely obvious and clear with the addition of the attenuator. As has been stated by Regal in other posts, using the attenuator makes the battery modded hiface a phenomenal transport!!
That was a very neat little test you set up Bubu.
Just to be clear, you're saying that the volume out of your macbook's optical connection and the volume USB of the modified HiFace from the same computer, when played through the headroom ultra micro dac were exactly the same?
I think it was on DIYiIFi that an attenuator was first demonstrated to have an effect with the HiFace. I don't recall, however, that the effect was anything more than a rounding out the edges.
Btw, were you using long cables or short cables?
USG