[jimlevitt]

I'm interested in the UltraDAC. The website says "Any good tracking CD player or DVD player with a coaxial digital output and the Ultra DAC are all you need for exquisite CD performance." Frank has mentioned in an earlier post that jitter is a non-issue with the AVA dacs.

I'd like some more detail on this, if possible. There are some dacs on the market (Benchmark and Lavry come to mind) that are specifically designed to be "transport independent," in the sense that the dac reclocks the incoming data. Most of the dacs used in the audiophile world - as opposed to the pro world - do not have such a feature, accounting for the vagaries of sound quality depending up the transport and digital interconnect in use.

Here's Benchmark's blurb from their website regarding this issue:
"Many DACs derive their system clock directly from the AES receiver making them very susceptible to jitter. These DACs can rarely achieve their rated performance in real world applications. By contrast, the DAC1 takes full advantage of our jitter free UltraLock™ technology. On the test bench, or at the end of 1000' of cable, the DAC1's performance is the same! Actually, we don't think you should have to be a transmission line expert to be a great audio engineer. "

How are the AVA dacs designed to render them immune from transport and cabling issues? What's the special sauce?

I always stuck to one-box cd players, trying to stay away from mix 'n match troubles. If dacs can outperform the better cd players while hooked to $100 dvd players, I'm in.

[avahifi]

"Jitter" simply is not an issue with our DACs.  Much more important priorities are that AVA DACS are still true 16-bit parallel processing units that can retrieve all the data at all frequencies on a single pass basis.  1-bit DACs simply cannot do this.

In addition, the Ultra DAC has an amazing hybrid analog filter (critically damped) and high current, low output impedance, ultra wide band output stage capable of driving any load downstream.  There are lots of DACs out there with impressive specifications with pure wimp IC output stages without the bandwidth and current drive to adequately drive their own necessary analog filters, let alone drive downstream loads and cables.  Check your output ICs, if they have 5 mA or less max output current and a bandwidth inadequate for the filtering job (needs to sink out all the switching frequencies and their harmonics, up to one meg or more} then what you are hearing from your CDs is not music.

The transport simply provides the digital data stream, which will be perfect if the unit is in good working order and follows the necessary error code corrections.  All the damage is done when the D to A and Digital filters and analog filters and analog output stage strangles on the data.

Can you hear the difference when the details are considered and done right with an AVA DAC?  You bet!

Regards,

Frank Van Alstine

[Charles Calkins]

Frank:
 There is one point that I have to disagree with you.
 In my limited experience with DAC's and transports I've found the better the transport the better the sound. Also a dedicated CD transport sounds better to me than a DVD player used as a transport.


                                        Cheers
                                        Charlie

[WEEZ]

Hi Dad! 

I agree with you Charles. However, you must note that Frank says "Any good tracking.........". The players they give away with a fill-up of gasoline prolly don't qualify....

WEEZ

[Zheeeem]

I'm interested in the UltraDAC. The website says "Any good tracking CD player or DVD player with a coaxial digital output and the Ultra DAC are all you need for exquisite CD performance."

...

I always stuck to one-box cd players, trying to stay away from mix 'n match troubles. If dacs can outperform the better cd players while hooked to $100 dvd players, I'm in.

The biggest single improvement I ever made to CD performance was to get a standalone DAC and run coax in.  That was an Omega DAC shortly after they were introduced.  I recently upgraded to Ultra and am exceedingly pleased.

My thinking is that a CD player is a transport and DAC in one box.  I would prefer not to have to upgrade both simultaneously, and I reckon that any reliability problems will lie with the transport.  So my preference is to keep them separate.

Given that now I have a great DAC I can, at my leisure, neurose all I want about the transport.  The issue then becomes - is the transport on my $100 CDP (or DVDP) "good enough" or do I need to pursue a transport with less jitter?  I have opted to use a cheap CDP as a transport and focus my resources where I think they will make the most improvement.  Frank has greatly eased my naturally neurotic tendencies by advising that with AVA DACs, jitter is not a significant issue.  I have played several different CD sources through Frank's DACs and was not able to note a significant difference.

[GHM]

Pick up a signal conditioner like the Monarchy DIP, GW Labs DSP, Digital Lens or Big Ben..I can assure you..you'll most likely hear a difference. Give it a try..some have 30 day trials. Especially with a inexpensive player ..even not so inexpensive players benefit for such a device.

Just one listen with a device like this will prove the transport does make a difference. ...Either that or your downstream gear hasn't evolved to the point where this is noticeable. I think you'll hear it as plain as day though.

[jimlevitt]

This is the point: if the transport makes a difference with these devices, the devices are not properly designed!

Here's what Robert E Greene, Absolute Sound writer and UCLA math prof, has to say about it, in reply to someone who reported from personal experience that different transports did not sound the same:

"Not if the input is buffered and reclocked on the DAC!
It is to my mind a matter of definition, nearly. A good DAC is one
that reads only the bits of the input. If the transport matters,
then one has a bad DAC. DAC manufacturers are rapidly figuring this
out--those who are going to survive anyway. Took them long enough
since buffering has been the stock in trade of the computer industry
for decades. What a nightmare if everything had to work real time
without buffering. Well, it just would not work , is what."

So back to my original question: how are the AVA dacs designed to handle the incoming data stream so that "jitter is simply not an issue"? Do they buffer and reclock? Or are they dependent upon the clock from the transport? I have no doubt that the rest of the design is superior. I'm only asking about the interface with the transport and cable.