[drez]

Quote:

 Well, I changed my power cord from computer to the Audio-GD DI and it improved very much. Now I'm buying another power cord for my PC to see what happens, I really don't know if this time there will be an improvement in sound because the clock is off the computer, but for the piece of mind...
 
 I don't feel anymore like maybe I should have invested this money in another piece of gear. By the way, looks like the upsampling works better than no upsampling. People say it sounds a little harsh without 'burn in' but this is exactly the opposite I found compared to the stock setting. Lets see what happens in some days, than I'll try to compare both again.
 
 One of the big differences I found with my DI right now was that the soundstage improved very much, stereo separation and there is more height, vocals are higher in space than other instruments, decay is longer too.
 
 And I bought the USB Isolator and the Furutech GT2 cable, I hope both improves the sound too.

With 44.1 khz material I find that the upsampling tends to smooth over a lot of the low level details and I would only recommend it if you have problems with the DI when running without upsampling.  Other reviews tend to concur that the upsampling isn't optimal for 44.1 material - but you may like it depending on personal preference.
 
Don't understand what you mean by "power cord from computer to the Audio-GD DI" - are you running some sort of power arrangement from your computer PSU?  Or are you running the AGD power supply?  Which power cable are you using?
 
 

 

[ninjikiran]

Cheap products that sound ok   I wouldn't associate them with high end though. 
Though the chip they are using in that spdif interface is a newer model.
Quote:

I'm not aware that C-media is associated with mediocre quality. Would you mind explaining why?
 
BTW, the folks at MHDT seem like a nice and knowledgeable bunch of folks. I've been asking some technical questions and they are keen to answer them...
 

 

 

[Sganzerla]

 Thats strange, drez, because with upsampling the first tought was very different from you. I'll be back again with a comparison soon, to see if I change my mind.
 
 Some time ago, I upgraded one of my component power cords and there was one left, so I tought, let's see what happens if I put it on my computer (that is my transport since) - the improvement was not small - so it stayed there.
 
I bought this DI and found a little improvement over my computer (computer with PS Audio AC3 power cord and DI with stock cable). Then I tough, what happens if I now change my PS Audio power cable to the power supply of the DI instead of the computer? And everything went in its place, the improvements were again not small. At this time the best power cable is in the power supply of DI instead of my computer - I changed what one would do.
 
 Now I need to put another power cable of the same quality on my computer and see what happens, of course this is not a small $$$ upgrade, but it may be worth.

 

[drez]

I would hesitate getting into computer power tweaks -AFAIK most of the noise from the PC power supply that may be affecting the USB output is coming from other components, not from the power cable, there's a whole host of things in a PC which may or may not affect jitter before looking to a power cord - eg computer PSU quality, hardware selection + hardware/software settings, hardware and software latency etc.  Another thing to think about is that just about any power cord is also passing on any line noise it has collected unless it is fed filtered power, unless you believe the theories some manufacturers put forward about skin effect and various other passive 'filtering' supposedly done by the cable (but never actually measured).  Typically what you get with audiophile products compared to Pro-audio is a complete absence of performance measurements, misleading technical descriptions and an inflated price - be wary.  Some of the above tweaks are testable (eg latency) which makes life easier to verify an improvement.  With a computer power cable it is very difficult to compare as you must first reset the computer before you can directly compare - not like switching out the power cable to the DI power supply ( I hope your tested thoroughly) 

IMO tweak away as long as there is a solid theoretical basis for your tweaks, or unless the tweak costs you nothing!

 

[Sganzerla]

 Drez, unfortunately even thinking that a power cable in my computer should not affect the audio, this is not what I found, and I'll try this again as soon as the new power cable reaches my home, and report back my findings.
 
 I'd like to see more people testing it, even for the power supply of the DI, and write here if they found any differences.
 
 

 

[drez]

I can't rule out that this wont have an affect - all I would expect is that a direct comparison will be difficult as listening samples will be at least a couple of minutes apart, and very bothersome to do 

.  Pretty easy to forget exact audio qualities when samples are that far apart.
 
If you already ordered one may as well do your best to thoroughly compare them - but I wouldn't personally be brave enough to shell out money to test it.

 

[svyr]

I can't rule out that this wont have an affect - all I would expect is that a direct comparison will be difficult as listening samples will be at least a couple of minutes apart, and very bothersome to do 

.  Pretty easy to forget exact audio qualities when samples are that far apart.
 
If you already ordered one may as well do your best to thoroughly compare them - but I wouldn't personally be brave enough to shell out money to test it.

that's why we should record the output and compare it objectively (pref using measurements )

 

[haloxt]

I've played around with power cables for source equipment and for the computer. I think stock 14 awg power cables are maybe 75-90% of $75 9-12 awg power cables, depending on how sensitive individual gear are to power cables. I believe power cable shortcomings become more noticeable when you have more, ie if you put a thin long power cable source equipment, and a thick power cable on a power amplifier, the amplifier will have a more stable soundstage and reveal how wobbly the source is making the sound. This increases if your speakers/headphones and cables are revealing as well. If you don't want to spend much on power cables, yet are curious, I'd recommend getting some monoprice.com 14 awg power cables, just buy a dozen so you're set for life . They range from $1-$2. http://www.monoprice.com/products/search.asp?keyword=14awg+power&x=0&y=0
 
For my computer, I use $30 14 awg power cables, 430w antec earthwatt psu (relatively low jitter) and an ac-215 power conditioner. Altogether, I think it makes a notable improvement in ccmputer as source. I got multiple mp3 players hoping the spdif output would be better, but my silly computer still has superior sound quality from usb . Cplay is the best-sounding software I've used.

 

[drez]

@haloxt how do you select low jitter computer power supply?

 

[kr0gg]

Quote:

@haloxt how do you select low jitter computer power supply?

 
i guess he meant low-noise

 

[haloxt]

Yep, I meant low noise and low ripple. There's sometimes a big variety of ripple scores, so look at the ripple rating before buying a new psu. The antec psu I have was replaced with a new earthwatts 430w model, which seems to have very bad reviews about the build quality, so I'd advise you to stay away from it.
 
This website has good reviews with ripple information. I wouldn't spend more than $75 on a psu though .
 
http://www.jonnyguru.com/modules.php?name=NDReviews&op=Review_Cat&recatnum=13

 

[drez]

good website!  I don't think I'm going to get much lower ripple than what my PSU (Antec CP1000) at my load (470W) is producing 

 - looks like less that 10mW:
Will be interesting to see if the DI psu makes any improvements, or whether I just get an Audiphilleo...
 

 

[catchedge]

How difficult is it to switch the semiconductor to something like a 74VHC04N as previously described?

 

[somestranger26]

Quote:

How difficult is it to switch the semiconductor to something like a 74VHC04N as previously described?

1 minute and a pair of pliers or a chip puller. Simple.

 

[wushuliu]

Before playing with power cables it may be a better idea to ensure your PC is getting good quality power from a power conditioner or similar like APC voltage regulator ($50 4 outlets on AMAZON). PCs are extremely sensitive to what's coming out yor wall, especially if you live in a big city. It took me a long time to realize this. For years I would get various BSODs and crashes (in different cities, with different gear) sometimes often sometimes not so often. When I moved to LA it got out of control and after I realized the bulbs in my apt. were also burning out quickly I began to associate power with PC performance. Once I got the APC voltage regulator/conditioner, I have had ZERO crashes regardless of where I live and after changing my PC gear many times. This is over a 3 year period. Again, zero crashes. Same with my laptop.
 
I'll let you make your own assumptions as to whether this would benefit sound quality and PC performance overall.