Why no UK built NOS DAC?

Hi,

Absolutely.

Well, in principle, IF S/P-DIF or AES/EBU are implemented correctly it matters zip if the connection is via optical or electrical connection.

Then the question of quality is limited to transport getting a good "read" of the CD.

From there, assuming no errors are encountered the DAC should reject all problems and provide correctly timed data with full data integrity to the DAC (possibly with integer multiple upsampling normally called oversampling, including interpolation or not applied). Any jitter in the interface should be stripped out, the crucial short & medium term clock stability should be determined only by the DAC's own clock oscillator (which is usually part of a PLL circuit of some sort).

I agree. In my view and experience the best digital input for a stand alone DAC is called a transport. This allows you to directly insert a CD into your DAC. The product is often called CD-Player.... :MILD:

What player have you got. Maybe it would be much easier to add a TDA1545 based DAC internally and feed it EIJ or I2S data?

Ciao T

 

Sorry dudes, guess I messed up by mentioning that Net Audio DAC - at least they're in the UK!

So, 3D, what type of clocking solution do you use in your design?

Do you have any digital inputs? Or is it exclusively a CDP?

Have you enjoyed having the engineering constraints relaxed for this project? Good luck with your commercial endeavours. Hope you have success and can then release different variants at lower price points :MILD:
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Suzuki dl1000 v-strom specifications

 

You have to interact with a CD player. It therefore has to be on show (for convenience). It therefore has to look good.

A DAC, on the other hand, has no such constraints. If it can be made small, it can be hidden behind other equipment or in a cupboard or whatever and who cares then what it looks like. I would be quite happy with a small black box DAC to hide behind my Squeezebox. The only criterion is that it sounds better than the Squeezebox DAC (and obviously has a TOS-LINK input).

 

Hi,

A single clock using a very low noise power supply and driving all clocks in the player using a suitable clock distribution/division circuit. Nothing fancy at all, just plain old traditional engineering.

USB is planned, not sure if it will make it into the first series. Adding other digital outputs or inputs would be pointless, hence they are not added.

The constraints are not relaxed per se. What was done was to avoid extreme measures (Ideally I should have preferred to use several TDA1541 per channel, balanced/paralell, possibly transformer coupled output stage etc....), without compromising the key features. So it was really not "relaxed constraints", and pressure to keep costs from spiralling without giving up much makes this very hard (if enjoyable) work.

Thank you for the good wishes, I'm afraid at lower pricepoints it may be difficult to realise something we are happy to release. I still have on the drawing board a "High End" Lifestyle system, which will be "all formats universal player" (including video) with Non-OS DAC (up & oversampling switchable) and Valves for analogue stage duties and also preamp section, with a seperate "powerpack" giving the poweramplification and supplying the fancy looking headunit (probably B&O styling cues - allways steal from the best).

I doubt however that we will ever make anything usually considered "budget", as the budget is simply too small to do much sensible with it.... It is just simple economics.

If you want a simple Non-OS DAC that is cheap, a CS8412, TDA1545, a 12V SLA Battery and a bit of perfboard cost < £ 50 including many other fancy parts and the IKEA Plywood box to put it in. Just make one.

Ciao T

 

I have long suspected that much of the appeal of the turntable as source is the endless amount of tinkering that can be performed - even without going anywhere near a soldering iron.
I further suspect that the stand alone DAC is a bid to steal a little of this tinkerability for the digital domain. After dusting your CD player what else can you do? (OK you can get out your pens and sprays and so on but that's not real tinkering)

Also, as buddha is suggesting (I think), there may well be other digital sources in the home which could benefit from the services of a decent DAC.

Lastly, CDP is Cyrus 6 - you think it may contain 'user serviceable parts'

 

You can take the lid of and add vibration damping sheet to it and also to any other surfaces that are a bit tinny.

You can also stick a blob of blu-tak on the capacitors to damp microphony.

 

Hi,

Doubtfull. Analogue is my main source simply because of the Music. Too much really excellent stuff issued on vinyl THAT I CARE TO LISTEN TO has never been issued on comparable quality CD (often the master tapes where well degraded, in many cases the final mix is "modernised" all sorts of stuff). Once it is propperly setup my turntable gets tinkered with it least of the whole system (not unrelated to it's size and weight I suspect).

As long as they use S/P-DIF (or AES/EBU) as interface there is a tight ceiling on how far things can go. In our case for our CD-Player the whole chipset and setup is 44.1KHz/16Bit only and is designed strictly to get best sound from CD. To allow other sources (except possibly a PC outputting 44.1KHz/16Bit data via USB) would be pointless.

If you want to reproduce DVD Audio (be it AC3 or actual DVD-A or hi-rez PCM using DVD-V) you need in my experience a DAC very different from what is needed for CD to get best sound.

The Cyrus I'd leave alone.

How about looking for a 2nd hand Marantz, Philips, Rotel, B&O et al Player of the right generation (TDA1541 DAC and Swingarm Mechanism), invest the money to have the transport PROPERLY SERVICED by someone who knows what they are doing, replace all the electrolytic capacitors (which will have aged past their "throw away by" date), finally bypass the digital filter and upgrade the analogue stage Op-Amps and re-adjust the filter to offset the sinc(x) rolloff and fit a decent clock (Tent Labs).

The resulting player still only sets you back reasonable money and will take on a lot of stuff out there and the amount of work is modest. After the Cyrus has been properly declassed by 15 Years old technology you can sell it and get a decent DVD Player as second source from the proceeds....

Ciao T

 

Hi,

In that case, as you insist on using S/P-DIF your choices as far as i can tell are:

1) Audio Synthesis DAX (has Toslink AFAIK)
2) Chord DAC64
3) 2nd Hand Marantz DA-94 or DA-12 (or the Philips Badged versions) which will however need a comprehensive restoration due to age
4) Weiss Medea
5) Lavry DA2002

I would probably recommend a 2nd hand AS DAX (which is UK specific and actually gives a reasonably low cost), ideally the UltraAnalogue version fitted with the HDCD Filter and then hack it so you can bypass the digital filter if you like (when my Shanling CDP comes back from it's long sojourn among potential customers I intend to convert the "upsampling" button to actually invoke Non-OS).

Lavry would be my second choice. Given that the Lavry costs more than our CDP will retail at (and has not got any "Toobs" for all that money) you can maybe see my point that it is easier to just include the transport syncronised up than to bother with a DAC.

BTW, for the record, my actual "fixed" digital player has been for many years a Pioneer DV-505, heavily modded. This is interresting insofar as it's "Legato Link" DAC uses a Digital Filter that behaves more like Non-Oversampling when faced with anything but a sinewave (later generation dispensed with that and use off the shelf Burr Brown DAC's set to "slow rolloff" filter) and in that it actually reads the CD asyncronously just like a DVD. The downside is that it plays no CDR's (but RW's for some reason!).

It has outlasted many DAC's and other players, some of the DAC's where marginally better but very little has been around that comprehensive outclassed that "el cheapo" player....

Ciao T

 

This sounds neat - who can offer such a service in the UK?

P.S. won't all these mechanisms reach their end of life soon / lasers and what-not?
________
Buy cheap vaporizer

 

Hi,

No idea. Any really old, longstanding HiFi repair shop?

What do you think the service is for, new laser, new motors, new rubber belts etc. Needs propper installation and setup, or it does not work as well as it could.

Ciao T

 

Why do you suggest/recommend this as a receiver (as opposed to any other receiver chip). Are there no others that are better at removing the effects of jitter from the input signal?

Ta

Chris

 

Hi,

Among those available it is the only decent non-SMD one and thus the only one suitable to easy DIY. It's jitter rejection is about as bad as any of the others, more modern alternatives from Cirrus don't materially improve jitter rejection and the other Receivers tend to rely on ASRC's for jitter rejection, which kinda makes the whole point of a Non-Os DAC completely moot.

If you want really low Jitter for a Non-Os DAC, add a secondary PLL, you can get a suitable PCB from TentLabs.com (xo-dac) and put that inbetween your DAC Chip and the 8412. Of course, if you go through all that effort you might want to implement a DAC better than the TDA1545 and suddenly the "cheap & easy trick" becomes complex and difficult and expensive.

Ciao T

 

Had a look in the cupboard at home and found a - Philips CD 610 - according to what I've googled so far it's either a TDA1541 or 1543 - no details of mech yet...

From what you are saying, is the idea of a DAC that will take inputs from eg. CD, satellite, hard drive and any other digital format fundamentally flawed?

 

I didn't think parts were available for the swing arm mechs any more? Certainly, when the laser in Henryt's Marantz CD10 failed (after only about 3 years IIRC, from brand new) Marantz could only replace the one part by tearing the whole mech apart, at hideous expense, and had a job sourcing the laser itself.

I have (well, my mate has it at the mo) a dead Marantz CD54 (swing arm, based on the Philips CD100) - any ideas (if the parts ARE available) how much it'd cost to rebuild it? It sounded ace when I got it (paid £15 for it in 1998). A bit less detailed than my then-Pioneer PDS-703, but I didn't really listen for "muscality" in that dim distant past, so not sure which one'd have been the winner in the PRaT/musicality stakes...

BTW - like the look of your CDP prototype, even though it's oddly reminiscent of an early incarnation prototype of the RCA CED Videodisc system (don't hit me!!).

 

Hi,

Maybe not via Marantz Service, but independent spares dealers probably have still remaining stock, worthwhile casting ones net.

Shanling found enough new whole transports to make a few 100 CD Players and to put a lot of spares on the shelf....

Ciao T

 

Hi,

Is this one of the "mostly plastic" generation? In which case it may be a good job for a learning excercise, but maybe nothing for long term.

Ciao T

 

Which mech do Shanling use? And in which of their players?
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Xxx Tube

 

Hi,

No, taking digital inputs via any number of conceivable serial or parallel connections and protocols is just dandy, AS LONG AS THE IMPLEMENTATION IS CORRECT.

The standard S/P-DIF and AES/EBU receiver implementations are not "correct" by themselves. They do not attenuate jitter well at all.

In CD digital audio we have several possible flaws and problems on the replay side (let me not get started on the recording side, we'll be here sunday evening).

1) Extraction of the Data from the medium, here errorcs can happen which standard CD error correction will conceal by one of the various methodes programmed in, but the data passed on will be not what should have been there.

As Audio CD replay is syncronous (that means each bit is read sequentially and only one pass is made) any error that is not covered by the various inbuild mechanisms will cause an error in the data read. With dirty/scratched CD's one may see significant rates of uncorrectable errors with certain CD mechanisms, 100's of frames per second (there are 44100 Data frames per second) are not unheard of, if rare.

2) If we have our data the next problem may arise if we wish to manipulate the Data in the digital domain. In principle, if we alter the data we "corrupt" it, as the output after the DSP will not be any longer the same as the input (intentionally so of course). Doing DSP transparently is non-trivial, a lot of ready made silicon has not got enough capacity to do the job well, even in this day & age.

3) Assuming the data read in 1) was correct and not corrupted by 2) the digital filter etc the next error is jitter, that is an error in the timing of the data, resulting in effect in the correct value at the wrong time, which for a signal that exists along the time axis as much as along means it is distorted just as much as if the data itself where corrupt.

Jitter is irelevant UNLESS a format conversion takes place, that is from analogue to digital (A2D), from digital to analogue (D2A) of from one sample rate to another (D2D known as Asyncronous Sample Rate Converter - ASRC).

4) Assuming the data was transmitted to the conversion device (in our case our DAC) free from data corruption (errors from 1 & 3) and free from Jitter the next error is an actual analogue domain distortion due to non-linearity in the DAC circuit or associated anlogue stages.

As you can see, there are problems in this which an external DAC will not and cannot address. Other it COULD address if the implementation was done sufficiently well, but sadly most DAC's use generic of the shelf silicon mostly in generic applications.

That means the serial protocols (S/P-DIF or AES/EBU) Jitter is not rejected to any significant degree. The PLL's in standard Cirrus Logic (Crystal Brand) only attenuate jitter above 10KHz, which means about 90% of the jitter that can produce significant audible changes remains completely UNATTENUATED.

Hence the sensitivity of these DAC's to transports, digital cables etc. A correctly implemented DAC will show non or very little impact from different transports and digitalk cables. Correct implementations however take a lot of serious design work and due to the relatively low volume cost also a lot in terms of specialised parts.

For example, a universal DAC capable of propper secondary PLL lock using VCXO's needs one VCXO per supported frequency, good quality VCXO's cost 10 - 20 Euro each, you need a logic to quickly work out which VCXO to select and so on. All VCXO's need seriously low noise powersupplies as well. By the time you have done all that fitting a single clock to the DAC and including a drive is a lot cheaper and most importantly easier, plus it gives you control over the items normally unaccessible as you do not what sort of "transport" the customer uses....

Ciao T

 

Hi,

Philips CDM4Pro Swingarm IIRC and the player is called in the UK "Omega Drive"....



Ciao T

 

mmmmmmmmmmmm checked out that 'Monica' on diyparadise.com, mmmmmmmmmmmm she's well worth a look, er sorry, yes DACs, Hey T, do you reckon that 1545 DAC kit that Yeo's selling will sound okay?? In your opinion of course.