sjsanford

I will say that one aspect of computer audio that's really been rewarding and a good counter to boredom is internet radio. The quality and variety is excellent and the freshness of well curated radio programming can make music fun again. The whole world is literally at your fingertips. For me this has been a very pleasant bonus to CA.

Hi @dkab. First, disclaimer: I am no expert, and my setup has been my first foray into the audiophile neighborhood, so I have little to compare it to. But as a V-DAC owner, I can tell you where I am with my research. I have a MacMini, and it looks like you're on PC, so my experience may also differ in that regard. I added a V-Link to my chain last month and upgraded my USB cable. I like it, but the jury is still out overall. I hear definite sonic differences among each of three following setups I've tried: 1) Mac Mini > Optical Toslink > V-DAC. 2) MacMini USB > V-Link > Coax SPDIF > V-DAC. 3) MacMini USB > V-Link > Optical Toslink > V-DAC. I've settled on #3 because it's the one that literally causes my toe to tap and gets us dancing to the music. For me, that musicality is better than hearing every last detail; I have also found some of the detail that emerges in both 1 and 2 to be shrill or fatiguing, esp in the highs, with vocals, strings, etc. In terms of upgrades... I'm like you - I've seen some pretty incredible mods on different forums, some of which involve replacing almost all the components on the circuit board! But I'm not going there. Soldering power cable and USB wires is as far as I'll go. Here are the 2 upgrades I am working on at this point. 1) A modest power supply upgrade to a regulated, linear supply. 2) Powering the V-Link from a 5V DC source other than the USB port that supplies the audio data from the MacMini. With each of the above tweaks, no matter how modest or extreme, most of the posts I've seen from people who do them report an improvement in sound. I'll try to summarize here what I've found to date on various forums here and elsewhere: For power supply. You've got 2 approaches: Go with 100% ready off-the-shelf solution, or one that requires a bit of DIY and soldering. Off-the-shelf will be more expensive. For the off-the-shelf stuff, I've found the following, some of which can get as expensive as the DAC itself: - Pangea Audio's PSU: http://www.audioadvisor.com/prodinfo.asp?number=PGP100 - Fidelity(UK) http://www.fidelityaudio.co.uk/mf_vdac_psu.html - Squeeze Upgrade (Dutch) http://www.squeeze-upgrade.com/musical-fidelity-linear-power-supply-vdac-p-1582.html - Russ Andrews (UK) - There was US another supplier, who does them for multiple DACs, that I was just looking at last night. But can't remember name now... in the $150 range I think. Maybe someone else knows. For DIY, I have found several options, that range from very basic (soldering the correct DC connector to a plug-in tranformer), to benchtop/open frame jobs and circuit board designs: ($15-$75 options) Jameco/Reliapro 12V linear PSU http://www.jameco.com/webapp/wcs/stores/servlet/Product_10001_10001_1953663_-1 MeanWell medical grade linear transformer MES-30A-1P1J (12V, 2.5A MES30A-3) http://www.jameco.com/webapp/wcs/stores/servlet/Product_10001_10001_2115426_-1 Samlex RPS1204 - http://www.samlexamerica.com/products/ProductDetail.aspx?pid=94 SuperTeddyReg - http://www.teddypardo.com/DIY/SuperTeddyReg.html ($$$ options) Acopian: http://www.acopian.com/single-l-screw-m.html or http://www.acopian.com/single-l-goldbox-m.html As mentioned in some other threads, all these V-DAC power upgrades should be taken with a grain of salt, as I understand that inside the V-DAC itself there is a DC-DC switching power supply, which many say rapidly becomes the limiting factor in the V-DAC's performance once the original wall wart is replaced. So it's up to you how "Extreme" you want to take the PSU upgrade. Myself, I'm probably going to try the Jameco linear supply and see where that gets me. (Although I'm really intrigued by that SuperTeddyReg...) As for the USB power tweak to the V-Link, I'll not go into that here...there is more info in other CA threads. (It definitely involves soldering and fun stuff like that.) -Steve

I recall reading that Sing-Sing chair rates low on galvanic isolation.

Probably 4. Love music and had always wanted high end system but was too cheap to take the plunge. Computer audio has been a great way to affordably at least move into the audiophile ZIP/post code - and it's geeky.

Is there anything else attached to your USB ports? If so, you could try disconnecting them and test it with the DAC as the only connected USB device.

these are all great ideas. I was hoping someone could also point me in the direction of sourcing a high-quality low-noise linear transformer -- the smaller type which AQVOX seems to be using in its setup.

- using all the different USB ports on the Mac? - in your screenshot you have 48khz selected. Try setting to 44khz if you havent already. if you're playing redbook rips, which it seems you are since 44 lit up on your toslink connection, then 44 would need to be set unless you're using a media player that automatically switches it on the fly.

Hi Eloise - yes, I had read in a few places that both the V-Link and the V-DAC have internal power conversions, with some saying they're not necessarily top of the line. (I seem to recall on another board people mentioning the V-Link has a switching converter inside.) This is one of the reasons I really don't want to over-invest in the power upgrade, as the internals on these devices might be limiting factors. (I understand there are some hard-core modders who have rebuilt the guts of these boxes, but I'm not going there!) This project is mostly for fun, and seeing if I can squeeze any modest improvements out of a modest investment (

definitely compare any upgrade like the V-Link vs. the Mac's optical out directly to the DAC. I have been doing some basic A/B sessions comparing the V-Link to just my mini's optical out directly to the V-DAC. Honestly, I'm still a bit undecided, although leaning toward the V-DAC. (Granted, my system's very modest.) I found the optical out directly to the DAC can hold its own, seems to have better imaging and some instruments stand out better, but it seems to be at the expense of a sort of shrillness I have found fatiguing, esp in strings and vocals. The V-DAC's imaging seems less "clean", but vocals, strings, complex music are much smoother and very easy to listen to. It's also "more musical" - we find ourselves toe-tapping or more likely to dance (seriously) with the V-DAC. This is all extremely subjective - bottom line is you very well may hear differences and it's definitely worth auditioning both setups.

Hi Eloise - You're exactly right - it is bus powered - and that's what some folks have been trying to change in order to improve sound by providing it with cleaner power. I have seen elsewhere on the forums several folks (Mark Powell, barrows, et al.) describing how they found other sources to deliver the 5V DC power to their (buspowered) DACs or VLINK instead of relying on bus power from the same USB port on their computer that's delivering the audio data. People have instead fed the VLINK power from a variety of sources: a different USB port, a separate AC/DC power supply, or batteries, and in each case usually report improvements. There are a variety of home-made hacks that achieve this (usually involving soldering, spare parts, and heat shrink tubing!), and also some off the shelf products (like AQVOX). -Steve

I'm working on some modest DIY power supply projects. My plan is to supply both my V-DAC and V-Link with linear regulated power. (I'm seeking to avoid the bulky Pyramid or Samlex style boxes.) I've found some good contenders at Jameco... a 12V linear regulated plug-in adapter (DDU120100M2250) and a 5V linear regulated plug-in adapter (DDU050100M2270). Each has decent, but not stellar, ripple performance (listed as max 50mV, but measured in the datasheets around 10mV). However, I saw the AQVOX folks have a plug-in linear transformer with much better ripple performance (~1mV). So my question is: anybody know a place in the U.S. to source the kind of low-noise plug-in linear transformer that AQVOX is using? I've attached a picture of it. Thanks, Steve

...after adding a V-LINK to my chain over Christmas, last week I chucked my el-cheapo (and long) USB printer cable and replaced it with a 1m WireWorld Ultraviolet. Significant improvement. So now I'm playing with the link between the V-LINK and V-DAC (auditioning coax vs. optical -- am leaning toward optical) but that's another kettle of fish. Steve

Another analogy to understand this... imagine a portion of a straight-line graph... just a simple y = x + 2 type function. The uncompressed .wav file would be analagous to the full series of numbers describing that graph. So starting at 0 and moving out, the function (the "uncompressed wav" version) would be (2, 4, 6, 8, 10, 12) if we're sampling for each whole number value of x. So the uncompressed "music file" would look like 2, 4, 6, 8, 10, 12. Imagine that's our "song". The compression algorithms for FLAC or ALAC seek to express that same data in a shorthand format. An easy way to do that is simply use the formula! It's much shorter than the full series of data. So that same music in FLAC format is would be "compressed" to something like (y,=,x,+,2) (more or less). Now, let's say we change just one element in each of files. Changing *any* one item in the compressed (FLAC) version formula "y=x+2" is likely going to have a crazy result when we "decode". So if y=x+2 gets corrupted into y=x+3, then "uncompressed" the music file would be (3, 6, 9, 12, 15, 18) which is much different from the original. Whereas changing just one item in the uncompressed .wav version might yield (3, 4, 6, 8, 10, 12), which will still sound a lot like the original song. If that makes any sense??

Looking forward to hearing back on your DIY battery powered usb cable. This is the CA forum at its best - folks trying stuff out, being creative, and sharing their impressions.

So other than confirmation from the manufacturer, is the only way to confirm this for our OP to find someone somewhere to hook up the analog outs from the NA7004 to a realtime analyzer while playing a 24/96 flac file?