[Tim D]

Ok, I sat down and tried to do more "objective" tests to compare with analog outputs of Denon. I felt there was big improvements especially in longer term listening and liked Ext Sync the most. Used my Beyers and some test tones from a bass mechanic CD and a switchbox, blah blah.

First I measured the boost of volume it gave with test tones using the VU meters on my audiosource amp. At 1 o'clock setting on my amp the D/IO will basically clip/max my amp as indicated by VU meters compared to more than 3 o'clock extra with the Denon. I don't know what this test showed, cept that the D/IO obviously has more gain, power, volume, or whatever knocking off some usable volume knob room (by perhaps 1/3rd!). It also did show however that it has a clean output in terms of S/N ratio since background hiss only elevates well beyond 1 o'clock and is nicely quiet at 12 o'clock with the D/IO and my amp. Would give the D/IO the advantage in having lower noise floor than the Denon (keeping in mind the ratio of the clean signal to background noise). The dynamic range as claimed in the manual as 108 A -wtd, and 105 typical make much more sense to me than the Denon's also very highly rated specs(forgot what they were).

Finally I did some more precise volume matching using the meters on the amp to do extremely short term A/B ing of some music which proved more difficult to discern differences. I than went back to actually listening to bass tones with the ridiculous idea that maybe I could discern an audible difference with test tones!

To my suprise I did make a few strange discoveries. 88khz is not completely seemless with my player as I originally thought and poorer locking does get a hold of it with some test tones breaking up(still curious to how well my soundcard or other digital transports will lock with these tests too). However external sync is fine. But the strangest quirk is that even with test tones there is a discernable difference that was even visual on the analog VU meters of my amp as slightly pulsating and extremely slight fading in and out of sound, that was also somewhat visible by the flashing monitoring indicators on the DAC. Wasn't quite sure why there should be pulsating wheter or not the tube was sucking power. Correlating with the sound was the warmth and VU LED's on the D/IO...very strange since warmth shouldn't even be lighting up in this mode I don't think. Some strange feedback...who knows?

All I know is that at least I'm not too crazy in thinking I hear overall effects if when it comes down to it, the D/IO is slightly different when it comes to the most basic tones. As for the wavering in and out I have no idea which to hand accuracy to, since in the liner notes it says on a stereo sub system it should indeed fade in and out, but this should be because one channel is half a hertz more than the other and there is some stereo cancellation effect, not something I'd imagine coming straight out from the DAC or effected by headphones. Anyhow I'd love to do bass tests with my speakers right now, but *sigh* theres other people.

Did a few more tests...never noticed wavering on the Denon DAC and was putting the D/IO's accuracy into question. However I did listen more carefully and noticed the slightest audible pulsating on the Denon as well and wondered if perhaps that even with volume matched, just more dynamics or "change" can come through on the D/IO. I switched the VU meters on my amp to be 10x more sensitive, and low and behold, there is indeed slight wavering in the needle exactly correlating with a much slighter audible pulsating. Indeed after more checking, with very short test tone tracks being repeated, the tone and VU needle would "pulsate" 3 times per playback of the very short test tone track at exact regular intervals. I figured out that even with VU meters matched on amp, BOTH the D/IO and Denon exhibited the exact same pulsating but to a much different degree. I also have to stress that without the visual guide of the VU meters, noticing anything out of the norm would be extremely difficult since you need to know when and what to listen for.

I removed the tube and the pulsating didn't behave much differently (although the warmth light won't shine now, and doesn't show the clip indicator til I drive up the input gain which is just quirky). If the D/IO is doing it wrong, than the Denon is doing it wrong to a much lesser extent. But if it is doing it right...the same also holds. Maybe the D/IO is just exhibiting greater dynamic range even at matched volume? Maybe it has to do with the greater voltage input to my amp. I can't figure out the slight pulsating phenomena in the first place, which could be in the test tones or transport section or amp interaction, or if its just supposed to do that as some sort of PCM coding/decoding artifact dealing with the limitations of DSP. I threw in my Panasonic portable straight into the test, and of course it was hard to notice anything at all, and of course it required even more work from the amp to bring volumes up to par. It was much more difficult to discern any pulsating in the Denon compared to the D/IO, and likewise I couldn't discern anything special out of the Panasonic and wasn't going to blow up my amp to try. And of course the tones sounded similar, but I always felt it lacked a certain dynamic control or precision compared to the Denon, much less the D/IO. If I were to boil things down into a silly hypothesis, I would say that regardless of matched volume, the D/IO is revealing greater dynamics perhaps in contribution by the greater voltage output. And that I could rank the D/IO, Denon, and Panasonic portable by subjective quality, and it would correlate with voltage output as well. Likewise I felt that each output gave the amp more or less to work with, the D/IO being more, the Panasonic being less. Also I had doubts this phenomena, whatever it was, was really a glaring inaccuracy of the D/IO and to a lesser extent the Denon, and something not in the Panasonic, seeing as the D/IO is a 24bit/96 khz pro audio DAC, the Denon utilizes decent but dated HDCD filter and older burr-brown 18 bit DAC's, and the Panasonic with its MASH DAC of course.

Anyhow all these strange and boring tests didn't really do much except show me that there IS even some discernable differences with matched volume on even the simplest tones. And that both D/IO and Denon outputs had the exact strange pulsating of yet unknown origin, but made much more discernable a presence on the D/IO regardless of volume. Overall I did feel major subjective improvements especially with long-term listening with the D/IO noting strong dynamics from the start. When doing objective volume matching with very short samples and quick switching with a switch box, differences were more difficult to discern. But when simplifying things to the simplest tones, quantifiable, repeatable, and discernable differences showed up just to make sure I wasn't insane about my overall subjective opinion.

I have no real strong conclusion to this, except that I am insane with too much time in which I try and discern differences into something repeatable, audible, and measurable. But this is just me...I like having objective conclusions to at least make sure I'm not crazy, and to let any other DAC/CDP skeptics know that there are differences. And I would consider audible, measurable, and repeatable differences in the simplest test tones as a pretty big difference alone. Ummm I'll give more subjective impressions if you give me like a couple of months to listen to all my music and equipment over again, but can only say that the sound so far makes me want to do exactly that.

 

[chych]

Hmmm I would be curious exactly how your vu meter would register once the DI/O's inputs are terminated with 75 ohm terminators...

 

[Tim D]

I terminated it by supplying it with an input, however again there is no difference in the slight wavering and pulsating of the needles on my VU meters.

This is not a random pulsating but occurs repeatedly at specific intervals...it is very slight, and is very exact in both L/R channels. It is not effected by removal or addition of tube. It is also seen in the very exact same nature on the Denon, but to a much smaller degree. I do not consider it to be a randomized noise or aberration. I do not know WHAT it is from, I just know the D/IO is far more revealing of it.

It does the same thing in 88 khz sampling as well.

I am also using very low bass test tones supplied on a bass mechanik CD and don't think I would have noticed the audible differences without the visual feedback of differences to correlate with.

On the same CD, the needles don't move or waver on a low-end frequency sweep. I just tried some test tone sweeps on a different CD and the needles don't move in the tones either although they also are much shorter and shift as well. It is when playing the low-bass tones on a particular CD that I notice this...maybe I should just rip the CD and see how it looks. All I know is whatever is causing the particular bass test tone tracks on that CD to behave a little strangely is much more revealing on the D/IO than other sources even at matched volume.

Actually I finally found my old test tone CD I made by myself...it again shows that on frequency sweeps, both DAC's are very similar as far as the VU meters go. Again it seems to boil down to how the D/IO is revealing something weird on some bass mechanik test tones to a much greater extent. My own test tone CD is just filled with pink, white, brown, purple noise. Some square waves, triangle, sawtooth, and sine sweeps who knows what I put on it. Anyhow maybe I can find something else interesting in terms of big differences in test tones I made, but as of now my verdict is that the D/IO is more revealing and dynamic of subtleties.

Ok I already made that statement before in my purely subjective evaluation, however it is pretty exciting (for me at least) to find my objective evaluation backing it up.

I don't like listening to one CD player jumping to another, where you *think* one is more revealing, but not for sure. Than you go back and forth and don't make any real good conclusions since now that some small details are made more apparent to you, you can also notice it in the other player as well as it has colored your testing and response. For example, in a long-term listening of an album like Princess Mononoke, I can glean so much more detail off the D/IO. In a short term A/B well obviously the details are still in the other player cause you know what to look for, so you can get slightly confused. I'm just saying I found an instance where I found slight difference on the D/IO that was also on the Denon but to a much lesser extent audibly and measurably in something as simple as a test tone. My subjective evaluations have always been pretty good IMO. For example I knew DT931 bass was extremely tight and extended beyond SennHD600 from short subjective evaluation well before seeing any graphs. Headroom's description of the DT931 always being "thin on bass". Yet the headroom graphs will show that the DT931 has better low-end extension. Don't use the normalized smooth graph(makes the DT931 look boomy on this "normalized" chart which is quite contradictory to thin bass), but the frequency response as shown on the product info page, since the normalized smooth graph is an average of many headphones with lesser bass extension. Also the DT931 is not averaged into their selection of this normalization of "ideal" headphones so it also is at a disadvantage in the smoothed normalize graphs compared to any other headphone that was selected as 10 best to be averaged out (this is pretty simple mathematics I hopefully won't need to explain this).

I guess I'm just saying, its nice to have a mix of objective and subjective evaluations to back up some claims.

 

[Nikolai Dot Org]

Since you are seeing the fluctuations in all sources, I would examine your power source. The fact that the DI/O is "seeing" further into the peaks must be a testament to its revealing nature. I can't wait to get mine.

By the way, Radio Shack finally has the upgraded power supplies in stock. They're about $27.

 

[Tim D]

Right now I think the D/IO is peering deeper into a fluctuation from the bass mechanik test tones themselves...again realizing that this fluctuation is just not random, but repeatable and very EXACT in duration of the test tone on both sources. My own recorded tones do not exhibit this strange behavior and they go on for longer periods and should also be utilizing full CD amplitude last I remember on the wav editing program.

Also I have phase check tones...just to comfirm AA findings that the polarity matters with the wallwart so make sure your system is in-phase. Likewise if a recording happens to ever be out of phase you can reverse the wallwart. On my system at least, the D/IO is in-phase or has the correct polarity when the wallwart wire faces downward as would be logical (I don't think the power leads are shaped to enforce polarity however).

I will look into the RS power supply upgrade however. I think it is important that you don't exceed the voltage (especially if you are running with tube), although people say it is regulated. My stock supply is 1300ma over the 800 one however, but I'll dig up peoples findings. Right now it seems like people find it to be a big improvement. But admittedly removing the tube was not something I would quantify as a huge improvement or change in my system, although it definitely would run better for longer hours given the cramped space and heat(however I did leave the unit on with tube overnight for at least 2 nights to see). I do think it was a slight improvement but I suppose it can depend on the heat. Both wallwart transformer and the unit itself seem MUCH cooler without tube which is a good thing. Power supply improvements usually translate to much better handling of busy dynamic passages so that would be what I would look for. Noise is also a good indicator, but I don't think tube removal made a huge difference there.

 

[Tim D]

Another mystery -

One more objective discovery which wasn't very positive. At first I thought the unit wasn't doing very hot with EMI/RFI emittance. In its current position it actually interferes with my FM tuning quite a bit...again ext sync being the least problematic, to the other sampling rates really thrashing the reception.

Played with it some more...it was very peculiar since positioning differences were minimal...than I discovered that the RFI/EMI not only changed according to sampling...but dissappears when my co-axial cable is removed from Art DIO!

At first I experimented if it was a power issue since power-down cleared up all the interference, but finally discovered that removing the digital cable completely removed the RFI/EMI interference. Please note I'm using a coaxial 75 ohm monster video cable I had lying around. I was a little confused since using my AM tuner trick on the unit itself did not yield any extremely noisy result above norm. But I think whatever noise there is becomes propagated by the digital cable somehow. My co-axial cables somehow emits lots of RFI/EMI when connected...and I will figure out if I have anything better. They seem to act like I'm moving my antennas when moving them around...which I don't really get much with the other cabling.

Hmmm further testing shows that connection to even the analog inputs/outputs seem to be conducting interference with my tuner. Strange since I've never had anything else complain to my tuner when being hooked up. I'll figure out if its a cabling issue or DIO issue or whatever. It seems effected by sampling modes but also connection, yet also totally changes upon movement of the digital cable alone...

 

[neworder]

I want to buy one of these Art DIO.

Where are some good places to buy one?

 

[Hirsch]

www.fullcompass.com had them for $123 but are sold out, not clear when they'll be restocking, or if the price will stay the same. It's not on their site, you have to call them.

www.samash.com has them for $189.

A local music store near me was able to get them for $159 (Chuck Levin's, www.washingtonmusic.com). If you call them they should be able to ship to you if they have them in stock.

Or, you could check out music stores near you to see if you can find a deal.

 

[Tim D]

Damn actually my Marantz FM tuner is just being really sensitive...and its the jazz or classical stations with the weakest sensitivity compared to all the Pop or classic rock stations that are getting nailed by any of my other components, especially the D/IO Denon combo. Hmmmm maybe I hafta re-arrange stuff or get better stuff than this dipole wire antenna crap.

 

[Nikolai Dot Org]

Full Compass is sold out? *WHEW* I just got my order in before the drawbridge closed!

Boldercables.com, unfortunately, does not have a "special price". The custom RCA interconnects and SP-DIF cable will cost $235... the price of TWO DI/O's. Nevertheless, with the DI/O's finicky nature, it's a good idea to have them. Long term stability and purity of signal in a source is worth the money, IMHO.

 

[Hirsch]

Quote:

Originally posted by Nikolai Dot Org Full Compass is sold out? *WHEW* I just got my order in before the drawbridge closed!

Fullcompass may be able to restock quickly. If not, it seems that someone comes up with a breakthrough price every few months. I got my first one at Mars Music, who was clearing them out at $119 or $129, depending on the store.

Quote:

Boldercables.com, unfortunately, does not have a "special price". The custom RCA interconnects and SP-DIF cable will cost $235... the price of TWO DI/O's. Nevertheless, with the DI/O's finicky nature, it's a good idea to have them. Long term stability and purity of signal in a source is worth the money, IMHO.

I found some digital interconnects (Elco DC-32) on audiogon that were being discontinued at $45 for a one meter cable. It's a solid silver conductor with a teflon/air insulator. I had been using Audioquest Digital 2 (twice the price), and the Elco was clearly much superior. I wound up buying half a dozen of them. I'm sure that there are better digital interconnects, but not at that price! Unfortunately, I think they are finally sold out.

I've been using the MIT MI-330 with a Calrad RCA to phono adapter. This doesn't provide attentuation, but so far I haven't needed it. Unfortunately, Calrad doesn't sell direct, and I haven't yet found a source for the adapter that doesn't require a mass purchase.

John Risch posted instructions for wiring attenuation into an RCA plug over at audioasylum, in the "Digital Drive" forum. I believe that this is the design that Wayne uses in his cables.

 

[Wayne1]

Nikolai,

You never told me you were a Head-fier!!

Here is the deal. If you send me an e-mail after you place an order with the website, or if you call in, TELL ME you heard about Bolder Cables from this forum I will give you 5% off one item and 10% off two or more items. This is the only forum I am making this offer on.

This offer is good for orders placed from 10/19/01 untill 11/23/01. If you placed an order before that time, get in touch with me and I will see what I can do.

Nikolai, I will give you the 10% discount. Use it to buy some more music.

For those who wish to make their own attenuating cables, here is a link to a picture and schematic of the network. I hope you are good with a soldering iron

http://www.AudioAsylum.com/audio/dig...ges/30858.html

Cheers,
Wayne

 

[Tim D]

I rearranged my setup, but on stations with somewhat marginal reception in the first place...either my Denon or D/IO will interfere slightly. But I have to practically apply voodoo positioning on my indoor antenna in the first place.

Anyhow I just have to shut everything but the tuner and amp for absolute best tuner performance. But than again I arranged things so my FM tuner never sounded better (I never noticed the Denon alone added haze to some stations either).

So I basically improved on both my Tuner performance, as well as my digital front-end...so I'm happy.