[avahifi]

You cannot measure this effect with op-amps as there is no way to access the internal voltage amp output.

However in an appropriate circuit you can hear the effect by playing with both the AD847 and AD817 linear op-amps.  They are essentially identical in design except that the 817 has a larger die area for the current amp section and thus less thermal feedback distortion.

Simply A-B them for bass linearity, power, and extension in identical circuits.

Slapping appropriate heat sinks on all the devices might help a bit, but the effect occurs on every musical cycle, probably too quickly to port the heat out of the mix.

Regards,

Frank Van Alstine

[plaf26]

Have been living now for a couple of weeks with the new Vision DAC and the Insight Double 240.  Wow!  Another order of magnitude improvement in purity and clarity.  For example, it's easier now to pick out an instrument in the orchestra and follow its melody line.  It doesn't get swallowed up with the rest.  I think this separation of instruments is what people mean by "air."  You can tell when an oboe takes over from a clarinet that much better.  As others have noted, I was a little concerned at first about loss of ambience (what I used to think of as "air"), but my unscientific guess is what we have here is significantly increased dynamic range.  If you set the volume so that the louder passages are what you're used to, the quieter ones (e.g., hall sound) will fall below the noise level of your listening room.  But when I crank it up to about 2:30, I get not only ambience galore but also pants leg flapping bass.  I love it!  Good thing I live in a house made of poured, reinforced concrete.  Might be a little tough on the neighbors in the summer with the windows open at midnight, though.  Way to go, Frank & Co.!  Thanks heaps!

[oneinthepipe]

But when I crank it up to about 2:30, ...

Wow, 2:30, just wow. 

(Is that AM or PM?)

Good thing I live in a house made of poured, reinforced concrete. 

No kidding.  My house would be a pile of rubble.

Happy listening.

[trebejo]

That's great, plaf26. I totally agree with your observations about the great clarification of musical lines that Frank's gear offers.

Congratulations, and enjoy the "new" tunes!

[smargo]

Have been living now for a couple of weeks with the new Vision DAC and the Insight Double 240.  Wow!  Another order of magnitude improvement in purity and clarity.  For example, it's easier now to pick out an instrument in the orchestra and follow its melody line. 

Your not allowed to talk about improvement in purity and clarity after a couple of weeks - according to wayne your hearing things and your just getting used to the sound. Its borderline ridiculous to say that the dac doesn't improve over time - Your right the seperation is very special - Im glad im not the only that heard lovely seperation after a couple of weeks.

[charmerci]

I will admit that I "am just hearing things!"

Years ago, I bought a pair ADS L810 speakers. (Geez, I wonder what ever happened to that company?) After a while, I grew to not liking their high frequencies - a bit harsh. Then after a while, I started getting into the AVA equipment. Over the years of listening to components recommended by Frank, the stereo equipment "sounded better and better." I read all his old Audio Basics newsletters which would describe what he was listening to, e.g. an "awww" sound in speakers which shouldn't be there.

So over the years by listening to Van Alstine equipment, I began to familiarize myself (it's called learning!) with what good sound sounds like. Now, I am a very good judge of finding faults in stereo equipment. Sometimes I can even tell you which one of the components is the culprit in an unfamiliar system.

I really don't understand why audiophiles are SO offended by the fact that we are humans and just might be able to learn by listening?

As another example, never having really listened before, do you think that any of us would be able to hear the difference between a good modern violin and a Stradivarius? Probably not, but I'm sure that any of us could learn how to do so.

Scientific research has recently shown that the brain changes well into adult years. Yes, we can learn and hear things that we couldn't before. It's called learning and there's nothing wrong with that!

[Big Red Machine]

Can someone post a pic of this new DAC?

[martyo]

Pete,

Back on page 4 of this thread Wayner posted an enhanced pic of what the EC version would look like, and the basic unit looks the same as the Ultra Dac.

[avahifi]

The Vision EC DAC is shipping right now.  You know, the model with two coax and two optical switchable inputs.  XLR balanced line out is also now available.

The new faceplates, back labels, and circuits are all completed and work great.

Several orders that have been waiting will be shipped within a week now as we get them all built and tested.

Best regards,

Frank Van Alstine

[smargo]

one really nice thing about the vison dac - is that it keeps everything really tidy and in order - there are hardly any ruff edges - expecially with good recordings - in other words compared to the bryston dac 1 - this dac really holds it own - its so hard to seperate them in terms of performance

Id even go as far as saying that the vision dac overall is a scooche better - for overall musicality - not night and day - but the vision costs a lot less than the bryston the last time i looked.

Im just saying - anyone looking for a dac in the $2000-$3500 range - this one seems very competetive - at least to the bryston

[smargo]

- in other words compared to the bryston dac 1 - this dac really holds it own -

I mean the bcd -1 (cd player)

[taoggniklat]

So I called my insurance company to see if I could claim a vision DAC as necessary equipment for my eyes.....


sadly they don't.

[wilsynet]

Is BNC input available as an option?  I have a transport that has BNC output.

[avahifi]

The Vision DAC has everything but BNC jack inputs.  We can't provide all possible input combinations at a rational price and keep the musical qualilty too.

However BNC to RCA adaptor cable ends are available inexpensively at Radio Shack.

I suppose we could supply a BNC input on a special order (satisfaction guarantee waved) for about $50 extra. We would have to go buy the part, hand modify the chassis, and then get a RCA to BNC adaptor for testing too.

By the way, I notice that my BNC fittings on my scope are more prone to signal dropouts than the RCA jacks we use.

Regards,

Frank Van Alstine

[Big Red Machine]

Is BNC input available as an option?  I have a transport that has BNC output.

I had very good results using the BNC-to-RCA adapter on previous electronics.

[Tom Alverson]

Is BNC input available as an option?  I have a transport that has BNC output.

$1.79 plus shipping from MCM:

http://www.mcmelectronics.com/product/33-510

[wilsynet]

I've read in a number of places that BNC termination is best, but honestly I have no idea and wanted to ask.  I'm sure an adapter will work just fine.

[Big Red Machine]

I've read in a number of places that BNC termination is best,

Agreed, we have all read those reports as well.  Whether we can actually hear the difference is the next thing.  I never could but YMMV.

[roscoeiii]

Any of the measurements for this DAC published yet?

[Wayner]

It's in the normal chassis as the other, older DACs, and the Vision EC DAC has a selector knob on the front face plate, where the normal selector switch location is on the preamps, to select one of 2 toslink or 2 coax inputs on the back.

See link: http://www.avahifi.com/root/equipment/dac/insight_dac.htm

Wayner