Why standalone DACs and not pre/pros?

[The Computer Audiophile]

Hi audiozorro - Very nice post. I agree with you on most everything you said. Options are never a bad thing and separate components provide options. Purchasing options and configuration options.

 

 

I am a fan of anything that sounds good and don't think one solution is best for everybody.

 

[tfarney]

"I think hi fi enthusiasts are very conservative and deeply suspicious of change"

 

This is so polite. Let me offer the rude, blunt alternative: Far too many hifi enthusiasts are members of a very small club who jealously protect their elite territory and refuse to hear that the march of progress, digital technology and world markets has blown open the clubhouse doors and allowed the uninformed rabble to walk through at a fraction of what they've invested. One man's opinion. Your mileage may vary.

 

Present company excepted, by the way. This place is refreshing.

 

Tim

 

[The Computer Audiophile]

That just might be the Post of the Month!

 

Very stern language that could be taken the wrong way by some, but I have a feeling it won't.

 

[watchnerd]

Daphne, can you elaborate on why "10 mHz bandwidth is needed to for higher sample rates of 24 bit and above"?

 

I have a high definition lossless file I downloaded from Chandos that has a sample size of 24bits, and a bit rate of 1419 kbps, or 1.4 Mbps, which is a tiny trickle compared to modern local area networking speeds, even WiFi ones.

 

[watchnerd]

"I think hi fi enthusiasts are very conservative and deeply suspicious of change"

 

Ashley, I think you've hit the nail on the head and, I would add, I think they're applying best practices (that evolved over decades) from the analog world to the digital world, some of which are less applicable or just flat out wrong.

 

If I were to apply the separates analogy to the computer itself, I'd have my CPU and RAM in one box, my storage in another box, my networking devices in a third, etc. If we're okay with the digital files residing in an 'all in one box' (i.e the computer) at one end of the food chain, why would we not be comfortable with all the digital processing (volume, codec decoding, subwoofer crossover filtering, etc) happening in a single box?

 

Granted, the last stage of converting to analog is subject to noise, interference, and other artifacts of a poor implementation, but that's true regardless of whether the box is separate or not.

 

And, if the pros are comfortable using a unified DAC/preamp solution *during the recording and mixing* process, why should consumers be worried about it during playback?

 

 

[Daphne]

Hi Watchnerd

 

Good question.

 

To calculate bandwidth for a TOSLINK audio connection use the following formula: Sampling Rate (44.1KHz to 196KHz) x Resolution (8 bit, 16 bit, or 24 bit) x Channels (1, or 2, or 6, or more) + 15% margin for re clocking to compensate for jitter = Bandwidth

 

44,100 x 16 x 2 + 15% = 1,622,880 or 1.62 MHz

 

196,000 x 24 x 2 + 15% = 11,068,235 or 11.07 MHz

 

(hope I calculated that 15% correctly)

 

For longer runs of TOSLINK fiber cable, one must be very careful to check the bandwidth first. Many manufacturers don't supply this information. Other cable makers using new high resolution poly will tout outrageous claims of 40MHz over a 200 foot run.

 

With TOSLINK audio cables, like all audio cables, there are buckets of snake oil to impress cloud-cuckoo-land tweakos. There should be good connectors so the fiber optics align with the lens properly, gold ends are completely useless. Proper shielding is necessary to eliminate reflection, three to four layers of shielding to prevent the escape of electrons causing signal loss is BS.

 

Daphne

 

[watchnerd]

Thanks, Daphne.

 

Do you have any recommended optical cables that meet the 10 Mhz requirements and aren't based on magic nor priced exorbitantly?

 

[tdme_tj]

Tim,

 

I am Tom "TJ" Jankowski, one of the principals of Overture Imports, Inc. in Ann Arbor, and we are the North American importers/distributors for AVI.

 

First off, I would like to thank you for your interest in the AVI ADM9.1s.

 

We are currently awaiting our first allocation of the ADM9.1s and the 10" Subwoofers from AVI. This initial order is coming via sea freight, and now that the ship has made way all of us here in Ann Arbor are as anxious as a six year old on Christmas Eve!

 

The current ETA for the ADM9.1s is October 6th. We plan to formally introduce and demonstrate the ADM9.1s and the 10" Subwoofer at the Rocky Mountain Audio Fest in Denver the weekend of October 10th-12th. If Denver is a convenient travel location for you we would be happy to have you give them an audition. Just stop by room 433 (Atrium Level) at the Marriott Tech Center.

 

Since building up a qualified dealer network for the AVI-d Digital Lifestyle products will take some time, we will be selling the ADM9 series speakers and the new 10" Subwoofers directly to consumers with a 14 day evaluation period. The retail price for the ADM9.1s in standard finishes (natural cherry and walnut) is $2999.00 per pair and in premium finishes (gloss white, gloss black and Santos rosewood) is $3299.00 per pair. The 10" Subwoofer will retail for $2150.00 a piece (available in basic black only). All of these prices include UPS Ground shipping in the lower 48 states and exclude sales tax.

 

I look forward to becoming an active member of the Computer Audiophile community and wish to thank Chris for both the opportunity to communicate with all of you as well as for his hard work on such an invaluable resource.

 

Cheers for now!

Tom "TJ" Jankowski

--

Overture Imports

US Distributor for Quadraspire AV Furniture and North American Distributor for AVI Ltd.

 

www.overtureimports.com

 

[haiku1]

Hi Tom

 

Good luck and all the best from Germany for you and your team from a happy and very satisfied 9.1 owner! :-)

 

[Daphne]

The good news: High bandwidth TOSLINK cable is just now being introduced using a new fiber titled High Purity Quartz. The bandwidth will exceed 10MHz over a 30 meter run. I'm told there are only around three companies on the planet who manufacture this fiber, the largest and best quality is located in Germany.

 

There are a number of audio cable companies who now offer the quartz fiber cables, but mainly under 2 meters in length. However, they are capable of transmitting high bandwidth files using the current TOSLINK standard.

 

Currently, high quality plastic fiber can meet or surpass glass fiber cables, but for TOSLINK use the max bandwidth is around 6MHz. Which is excellent because most plastic fiber is limited to around 4.5MHz or less.

 

So, transmitting 24/96 files on a top quality plastic fiber cable is no problem, and one can easily find cables up to 30 meters or more.

 

As you can see from the bandwidth formula I supplied, TOSLINK falls short for transmitting high bandwidth 5.1 or 7.1 audio signals being used for high resolution movies like the new Blu-ray format. Therefore, Toshiba (TOShiba Link) has introduced a new TOSLINK standard which can transmit a higher bandwidth over greater distance using a different LED light source and interface. Perhaps there will be a presentation at the 2009 CES. In the next year we should see this new standard being installed in A/V receivers, and maybe even DACs.

 

All the audio industry touts about fiber cable is the advantage of not being effected by any electronic interference. However, the number one key factors are speed and energy. There is no copper wire that can transmit a digital signal faster than fiber cable, and it requires a small fraction of energy to do so. A good illustration would be the old Cray Supercomputers back in the 1980s. One tenth the size of a IBM mainframe and thousands of times faster. The last largest prime number was calculated to a Cray. It produced the number in a matter of hours which would take any other mainframe more than a year to compute. Cray connected all the mother boards with fiber optic data lines thus greatly reducing heat, the amount of energy needed, reduced space, and greatly reduced the weight. The telecommunications industry immediately embraced the technology. 20 years later fiber cable being employed on a large scale.

 

A good deal of high quality fiber cable is used in the medical field. Hundreds of surgical procedures now use fiber optics.

 

I know of a company in New York who manufactures just fiber optic cables. One of their small niche markets is TOSLINK. Mostly cables for the recording industry. They are very reasonably priced and offer lengths over 30 meters. Lifatec, http://www.lifatec.com will be including a line of high bandwidth TOSLINK cables using the finest quartz fibers sometime in the next month or so.

 

I have a single quartz TOSLINK cable at home, one meter long. Cannot recall the manufacturer, but I paid something like $45. I have two 3 meter long cables from Lifatec which uses the finest quality plastic fibers available, the ends are polished, with a quality metal end connector. I know a couple of guys who install home theater systems and use TOSLINK often. I will be home in a few weeks and ask them for a recommendation, but I think they gave me the Lifatec cables.

 

Daphne

 

 

[Ashley James]

I'm afraid that we insist that our customers use the cheapest possible optical digital cable they can find with plastic plugs on the end and these work perfectly in up to 10 metre lengths. They might do longer but we haven't tried.

 

The reason we did this was that on the early models we found that people were buying expensive high end, fibre optic cables and that they were so heavy and cumbersome that they were snapping the socket off the PCB. Now we've made the hole in the back plate too small for them and we advise people not to spend more than £3 if they can help it.

 

This is pragmatism at it's best.

 

Ash

 

[The Computer Audiophile]

Ashley - I've been meaning to discuss the downsizing of the hols in the back. The only potential problem is the limited number of cables that have standard Toslink on one end and Mini-Toslink on the other end. these are required for the Mac optical output. There are certainly adapters, but many people aren't fans of adapters, including myself. Since the cables are so cheap maybe AVI can consider including one with the purchase in the same fashion as you include the interconnect cable between the two speakers.

 

Just an idea.

 

[tfarney]

Tom,

 

Thanks for your detailed reply. I'm afraid neither Denver nor Ann Arbor are too convenient from here in Charlotte, NC.

 

Tim