trying to learn what a dac is and does

MikeCTM2 · « **on:** 14 Mar 2004, 03:37 am »

hi i don't know much yet and would like to learn and get the basics of understanding a dac. a dac is an external device that goes in-between your source unit (cd player) and the pre-amp right? its purpose is to take over responsibilities previously handled by the source unit, if for example, no dac was being used, right? there needs to be a digital cable from the source unit to the dac and from the dac to the pre-amp just regular rca's/interconnects, correct? does a dac require 110-120V AC to operate? what type of digital output is required of the source unit?

PJ · « **Reply #1 on:** 14 Mar 2004, 03:53 am »

A CD player is essentially a transport + DAC.

The transport is the drive itself, it reads the CD, and outputs a digital audio stream.

The DAC converts the digital audio stream into two analog channels, which we listen too.

In reality, the DAC itself is usually an off-the-shelf integrated circuit from one of the big semiconductor companies, such as texas instruments. However, it requires a lot of external electronics to function.

The connection is:

Transport - Digital cable - DAC - Analog cable - Pre/amp.

The digital cable is usually coax, although it can be optical. The information is the same, merely the medium on which it is transmitted varies. Of course, both have to be using the same connection.

A stand alone DAC naturally requires a mains power supply.

MikeCTM2 · « **Reply #2 on:** 14 Mar 2004, 04:21 am »

great info thanks now i need to figure out the digital connection, which i'm completely unfamilar with. i have the sony dvp-s330 dvd player currently. it has coaxial digital-audio output and optical digital-audio output. i've been looking at scott nixon dacs and the ack! industries dack! i'm particularly interested in the scott nixon tube dac. what digital cable would i need?

Rob Babcock · « **Reply #3 on:** 14 Mar 2004, 04:45 am »

Most would agree that a coaxial digital connection is preferably when you have a choice. Both the DACs you mentioned will accept a coax (someone correct me if I'm wrong).

bubba966 · « **Reply #4 on:** 14 Mar 2004, 05:02 am »

Quote from: MikeCTM2

what digital cable would i need?

This would work...

'course it's kinda overkill for that setup...

MikeCTM2 · « **Reply #5 on:** 14 Mar 2004, 03:35 pm »

i went to the bolder cable website and had a look around at the different digital cables they offer. basically they have two kinds. their $75 cable and then the ultra bubba $700

cable pictured above. with regards to the former, there are four types, rca to rca, rca to bnc, bnc to rca and bnc to bnc. which one would i wanna get?

bubba966 · « **Reply #6 on:** 14 Mar 2004, 03:41 pm »

Yeah, the pic is of a rather extreme digital cable...

Anyway, you'd want an RCA-RCA digital. And if you went with Bolder (which is a damn good cable), I'd suggest the regular cable with the WBT Copper NextGen RCA's ($125 for a 1M cable). That would be one of the best digitals you could possibly get without spending too much.

The regular Bolder with the Copper Eichmann RCA plugs would be a good cable as well. But the WBT NextGen plugs are a whole lot better and would be worth the extra $40 it costs to upgrade to the WBT's over the Eichmann's.

nathanm · « **Reply #7 on:** 14 Mar 2004, 07:27 pm »

Hi Mike. This here cable fulfills all the requirements for a proper shielded 75ohm coax. It's the Elemental Voice Digital Ravensong MkIV, hand-built by skilled artisans and annointed with the sweat of Zeus. Yours for a real world, non-insaneo price. PM me for details.

Rob Babcock · « **Reply #8 on:** 14 Mar 2004, 07:53 pm »

Do orange and purple really match? Is it just me?

Still, cool looking cable.

nathanm · « **Reply #9 on:** 14 Mar 2004, 08:36 pm »

Orange and purple are very close complimentary colors.

Rob Babcock · « **Reply #10 on:** 14 Mar 2004, 08:42 pm »

I think an Orc would wear them together- or is that racist?

lonewolfny42 · « **Reply #11 on:** 14 Mar 2004, 11:11 pm »

Quote from: nathanm

Hi Mike. This here cable fulfills all the requirements for a proper shielded 75ohm coax. It's the Elemental Voice Digital Ravensong MkIV, hand-built by skilled artisans and annointed with the sweat of Zeus. Yours for a real world, non-insaneo price. PM me for details.

Does it glow in the dark ???

nathanm · « **Reply #12 on:** 15 Mar 2004, 04:39 am »

Not in the dark, but in sunlight, yes!

Humorous descriptions aside, I AM serious about this cable. You don't need to spend a fortune on wire, that's what I am saying. Not even a small fortune. They (the industry) make you think you're buying something special because it's been dressed up to look pretty and\or they've got some English major on the payroll who's got a way with words. Don't go down this road - it's a waste of money. You can get 'pretty' cables without taking out a loan. How often do you see them anyway? Maybe once when you install them, then they're hidden away. These won't come with an armored suitcase or silk pouch but they will connect your CD player to your DAC without a lot of fuss. Then you can forget about it and put the rest of that money towards something practical and affordable; like a ziplock bag of sawdust from Shun Mook.

To entertain the idea of spending $700 on a piece of copper\silver whatever is fine; but it should mean that you have already done everything possible tweaking things acoustically and speaker-wise in your room. If you have and you have plenty of disposable income, hey have at it, but until then don't believe the hype. Trying to affect meaningful differences in your system with different DAC cables is like painting a barn with a toothbrush. Besides, the look of most expensive cables can be easily replicated with a little effort. (although if we're talking asthetics then Kimber Select takes the cake - they went the extra mile and had little wooden barrels and square holder-together thingies made. Nice touch. That and they have some seriously kick ass photography to show off their audio jewelry. Bolder has some really great photos too, I like the rocks.)

Although the RCA connector isn't ideal for digital as opposed to BNC (for electrical whatchamacallits) those Canare RCA plugs cost approximately $3.00 each and are far and away the best I've ever used. Not only are they cute as a button, but they are built like a brick shithouse. (back when brick shithouses were cylindrical, silver and knurled) These cables have transformed the sound of my system! (from one which didn't have enough cables into one that did).

Rob Babcock · « **Reply #13 on:** 15 Mar 2004, 05:43 am »

I think you could probably improve them sonically by cryo'ing them, Nathan. Possibly exposing them to a really powerful EM field might polarize the crystal latice structure of the wire, too, somewhat improving the sound. Or to really improve the sonics you could, uh, charge more for them! From what I've heard, that always improves the sound.

nathanm · « **Reply #14 on:** 15 Mar 2004, 06:04 am »

You're on the right track Rob, but actually there is one KEY ingredient which I don't have. But I can't tell you what it is. Trade secret. You understand, right?

bubba966 · « **Reply #15 on:** 15 Mar 2004, 06:15 am »

Yes, the digital I jokingly mentioned in the pic is a most expensive cable. And one which is severely excessive for a Sony 330 & Ack!/Nixon DAC.

However, you're not going to be able to replicate that particular cable on the cheap as you're not paying for looks. There's $500 in the 2 Bybees & the RCA's alone. Then you've got to add the cost of the wire, additional shielding, heat shrink, cap, Techflex, solder, etc. Sure, nothing terribly expensive there, but it adds up to a few bucks. Then it's gonna take a bit of work to build such a cable as it's not just slapping plugs on wire & adding the Tech & Shrink. $700 seems like a more than reasonable price given the cost of materials & time it takes to build such a cable.

And yes, that sum of money is usually spent better elsewhere. Unless you've already tweaked/maxed out everything else.

I will order one of those cables for myself at some point. But I do have better places to spend my $ at the moment. I won't have a big problem with the cost as I'll be upgrading the playback of 7 speakers & 2 subs with that single cable.

I do think though that a digital with good plugs (either Eichmann's or WBT NextGen's) would be a good match for the above mentioned components. $75 (w/copper Eichmann's) or $115 (w/copper NextGen's) for a very good digital cable isn't insane to use on a $500 DAC & $400 DVDP...

Rob Babcock · « **Reply #16 on:** 15 Mar 2004, 06:45 am »

I'm guessing unicorn tears or elf sweat- am I close? Hey, you can still raise the price!:lol:

Mark_Walsh · « **Reply #17 on:** 6 Apr 2004, 01:35 am »

Dear All,

Could someone please explain the difference between "standard" audio cable (RCA to RCA), Video 75 ohm interconnect cable (RCA to RCA), and digital cable to me please?

If there is a bargain basement bin of VIDEO cables, do these work satisfactorily, better or worse than AUDIO cable for an AUDIO application?

Regards,
MW

MikeCTM2 · « **Reply #18 on:** 7 Apr 2004, 02:31 am »

recently i was going through my aunt's mini home theatre set-up that her satellite tv guy had done. i looked at the toshiba dvd plyr and said oh he forgot to plug in the 'white' or 'left' audio cable for the audio out. then i looked down at the yamaha receiver and noticed the same thing. i thought it wasn't an accident then and took a closer look and saw he was using the 'red' or 'right' side of a standard analog audio cable to make the connection between the dvd's coaxial dig out and the rec's dig in. i didn't know that the cheapest little rca audio cables you could find could be used to make this digital connection. i'm hoping someone can enlighten me on this. is this a valid connection/will it work? how close in performance is it to a true digital cable?

i think the video cable and digital cable are the same if you mean RG-59 or RG-6 (sat tv) compared to a digital cable. a standard audio cable doesn't seem much like a RG-59 or digital cable but then that's what i saw being used as a digital cable. regarding your second question, i don't know either but i guess worse. hopefully a more exp audiophile will come along

nathanm · « **Reply #19 on:** 7 Apr 2004, 09:06 pm »

There are numerous arguments available online with guys cussing each other out about digital cables, but here's a practical answer: The regular audio cable is a valid connection and it should work. However, it isn't ideal - the RG-59\video type cable will be better. The digital cable is supposed to have a "characteristic 75 ohm impedence" as opposed to the audio cable, which has...something else. It's related to the cable length, the type of connector, the layout of the conductors in the cable assembly and all sorts of other blather which could bore you to tears. Hell, they aren't even supposed to use RCAs for this application (BNCs are better) but apparently the trend snowballed and the cat can't be put back in the bag.

Anyway, for the DAC you want a shielded coax cable with good connectors to avoid jitter and other gremlins which will haunt your dreams and give you audiophillia nervosa. Basically the digital cable is carrying much higher frequency energy than the audio cable is so it needs extra love and attention to ensure all the bits get to where they need without any corruption. You don't need to sell your children into slavery to fund this cable purchase either, as many would like you to believe. You can get the required characteristics in the cable for a few bucks, but you might have to sacrifice the velvet-lined leather carrying case with handcuff.