Just a thought...

[bretty]

Hi all,

I've only owned my system for a couple of months and love the sound of it. However, I am intrigued by the frequent dicussion on this site about external DAC's. When It comes to the technical side of hi-fi, slap a dunce cap on me and put me in the corner, cos i'm still gettin me noggin round it. So, I have a couple of questions for you all:

Is the DAC mainly responsible for the quality of the sound?

I hear a lot about external DAC. Is it not possible to udgrade the DAC(s) that are in the CDP?

It's jargon to me, at the moment, but i've just looked up the spec of my Rotel and it has '20 bit, 8x oversampling twin differential Burr Brown PCM63, Pacific microsonics PMD 100 Digital Filter'. It's a ten year old player. Has DAC technology moved on since then?

Many thanks to all that reply 

 

[Anonymous]

No takers?ÿ

1). The DAC and the transport affect the sound (though this is debatable dependent on what DAC you have). DACs made for the audiophile world tend to be more coloured than DACs made for the studio world which strive to be as transparent as possible.

2). If your CD player has a digital out you can bypass the internal DAC and plug it into an external DAC.

3). You will hear results if you added, say the DM to your Rotel.ÿ

 

[bretty]

thanks Octopo. My player has a digital out, so I could do the external DAC thing.

Anyone know the answer to my other question: can the Rotel's DAC's be udgraded? It's just that I read somwhere that the DAC chips themselves are dirt cheap (a few quid), so could be much cheaper than getting an external.ÿ

 

[Anonymous]

As components DAC's are cheap as chips (sorry for the pun), but it's all about the quality of the circuits that feed in and out of the DACs.

I know they are a couple of companys on eBay that offer upgrade services for certain CD players but don't know if they will upgrade your particualr model, infact looking at one of there upgrades they don't seem to change the DACs, just the power supply to them.

This I presume shows how important the supply to the DACs can be.

I have a CA DacMagic external DAC to use for lossless files and for the money (£200) you cannot go wrong. I think Richer Sounds do a 90% money back deal if your not happy with the product, but don't quote me on that.

Garry

 

[bretty]

Thanks, Garry

 

[Anonymous]

You said dunces cap, so I am going to point out the DAC stands for Digital to Analog Converter.

Typically the digital format is PCM stereo (Pulse code modulated). A CD is 16 bit, 44.1Khz PCM. So you have a digital representation of the analogue sound wave. It is represented by a 16 bit number (-32768 to +32767) showing the amplitude of the signal at an instant in time. It's 44Khz so this amplitude is being recorded 44,100 times every second.

So every 44,100th of a second the DAC is reading a number between -32768 and +32767 and then translating that number into an output voltage (usually between about -1 volt and + 1 volt). Repeatrepeatrepeatrepeat....

But mine is 20bit? yes, oversampling is very often used on DACS, which is akin to displaying upsampled 480P DVD video on a 1080P screen. It doesn't look nearly as good as true 1080P, but it still looks better than 480P on it's own.

The advantages of an external DAC can be, amongst other things:

Zero interference in it's power supply caused by current draw from other components.

Near Zero analog interference due to other signals being physically nearby in other wires (be they audio signals or not).

No chance of this being a piece of equipment where the manufacturer decided to cost save on the DAC quality, like some systems might.

The only real dangers of going the exernal DAC route is if you already have a male member compensator of a hifi that has fantastic DACs fitted that, combined with all the other bits in their environment, outclass any external unit you're willing to shell out for.... or just make the benefit not worth the cost. ultimate the last bit is up to you though.

A tip.. if you have a surround processor you can experiment with using the processors DAC or the CD players DAC (or your computer soundcards dac) via analog leads vs coax.

This is how I worked out that the DAC in my rotel 1068 is rubbish.

 

[bretty]

WOW! Now that's an answer! The best part is that I understood all of it,ÿ

ÿThanks for taking the time, fella. Much appreciated.

Brettyÿ

 

[bretty]

gary_london:I know they are a couple of companys on eBay that offer upgrade services for certain CD players...
Oooh, I like the looks of that upgrade company. I've given them a call. You're right, they don't replace the DACs, but do upgrade pretty much everything else. I'm gonna take a punt, I think.

 

[Anonymous]

Interesting,

So a £200 DAC would be pointless connected to a £3000 CD PLayer?

Would a £1000 DAC benefit a £3000 CD Player?

Cheers

 

[bretty]

wickerman68:
Interesting,

So a £200 DAC would be pointless connected to a £3000 CD PLayer?

Would a £1000 DAC benefit a £3000 CD Player?

Cheers

I think that is the point, yes.

I've been doing a search for the last couple of days, and it seems that the dacs in my machine, coupled with the hdcd digital filter are, although ten year old tech, top notch. So, I don't think something like the DACmagic would be an upgrade for me.ÿ