DAC Info that may be helpful

CJROSS

Retro – Beekeeper

Jeez dudes a real hifi thread, marvellous !! I share a lot of your views dudes about transport quality and I know that at the higfher end of the spectrum when using a DAC that can be run off a transport with superior connections such as the DAC 20s ie its 110 XLR input then that is the way to go, but I think in the middle regions of the hifi world (Ie in sub £1000 CDPs) there are very acceptable transports available that can be fed into good quality DACs like the TAG DAC 20, A DAC that has had great attention paid to recovery clocking and the like (this makes transport less critical IMHO), For example the Pioneer 646A had very low jitter traces in one recent review with a Paul Miller lab report Ive seen, the old Sony QS range of FPM puck CDPs 930 & 940 had very small amounts of jitter, does this make then acceptable as transports ? FWIW the best design Ive seen recently for a design of CDP that has had lots of attention for active jitter supression from the digital output, is the £1000 Creek CD53 :

http://www.creekaudio.co.uk/products/cd53.asp

With a new customised ultra low jitter master clock and extra circuitry to reduce jitter from the Digital signal Processor, the CD53 truly sings. A re-clocked, low jitter, transformer coupled, co-axial and optical digital output makes it possible to fully realise the potential of high-end stand alone DAC, provided the correct type of interconnect is used.

To provide a useful upgrade path, the D to A converter, high quality master clock generator, jitter reduction circuitry and regulated power supplies are sited on a separate printed circuit board that can be removed and replaced by new or emerging technologies in the future.

I call that good design for an Int. CD player with a view to using it as a transport does the CD72T follow this level of design ? AFAIR the Arcam uses a Sony mechanism and usign a mid priced Sony ES CDP will beat it as a transport, even old models long since replaced.

FWIW Michael I know a lot of dudes who have added that very DAC to a bewlidering amount of transports and all report improvements in their original playback. I added it my system and it is a truly wonderful unit for example Im pretty happy what it can do off a £500 DVD player BTW, Does your DVDR not have an optical output in addition to your coaxial out ? if so run coaxial to DAC, then optical to AV amp for DTS/DD as Retro has said above. If not the TAG DAC may not be for you as Ive heard a dude mentioning that when used in that configuration ie looping a 48Khz signal from the DAC output, made a much leaner sound (the TAG reclocks the info from the DVD player) from his AV amp, best running 2 cables as suggested ie coax – DAC & optical – AV Amp. BTW I think buying an integrated CDP below £1000 is not up to what you could achieve with adding a £450 DAC.

Ask yourself this dude, you have a transport already are you willing to buy one again in an integrated CDP, this will curtail your sound per pound upgrade in the DAC department. When you can in effect buy a DAC alone the whol cost of the upgrade going on the DAC alone, for example the DAC 20 cost £1200 when new can adding a sub £1000 CDP outshine it ? not IMHO.

michaelab

Thanks CJROSS.  Unfortunately my DVDR only has a single coax digital out - no optical.  Are there any SPDIF splitters out there that I could use to split the signal in two, one for the DAC and one for my AV amp?  That's assuming of course that a DTS signal won't damage a DAC20 - opinions?

I might e-mail TAG to see what they say.  If I get a DAC I'll have a dilemma:  use it with my DVDR so sticking with just one transport for DVD and CD and then have a spare CD player or use it with the CDP to get probably even better sound??  I already have a spare Arcam Alpha 6  stereo amp so if I could extract the CDP from my system all I'd need is a pair of speakers for a dedicated stereo music system - but then if I was building a dedicated stereo system I'd probably want the DAC there, or at least a newer and better CDP

I have to say that £450 for the DAC 20 is a most tempting proposition...but as a long standing Formula 1 and Ferrari fan I've long harboured a deep hatred for the McLaren F1 team and anything associated with it which I will have to overcome

Michael.

dts_boy

lol!
michaelab, excellent reason for not getting the dac! i too am a BIG ferrari fan and got a lot of greif of my wife when i defected and bought one. its well worth the money though, as many have said, with a decent transport (i was using an arcam dv88) it is quite suprising at how much better it is. BTW i compared it to a £2k cd player which was my alternative and the dv88 with a dac20 sounded better, to me anyway!go on, you can always stick a ferrari badge over it

CJROSS

Right you Tifosi Ferrari luvvin Muthas put em up1! put em up I say !!

No problem Michael, FWIW mine is run off a Pioneer 717. DTS I agree about the £2K CDPs BTW, I get quite animated when hear some of the crap (IMHO) that is spouted about sub £400 CDPs being superior to this DAC due to it not being connected to a £1000 pure CD Transport using balanced connections (which I agree does sound top notch, just for me a £600 DVD player does as good a job)

Anyway not really a big F1 fan, Ive really went off it this year as have many other people, I effectively watch the first 5 minutes to see if anyone has the balls to give schummie a run to the first corner. Generally they dont so its zzzzz time . IMHO of course.

Anyway you boys wont be in F1 next year

michaelab

I asked them if the DAC20 would passthrough the DVD bitsream signal (DD 5.1 / DTS) unchanged through its digital out.  Here's the response from Mark Walker on the helpdesk (I hope he doesn't mind me reproducing it):

So YES you CAN use the DAC20 in the manner I was hoping....

Oh God if I order one now my wife will kill me

I need a "cooling off period"...

Michael.

CJROSS

Hey Michael great news dude, beware though that when you send a pure DTS signal through your DAC 20 to the AV processor, that the CD line input on the Amp is not switched on : I would not imagine that you would do this, ie it would be set to DVD for enjoying 5.1 surround, but in the event of this happening there is a chance of frying your tweeters on your speakers due to the resultant noise that DTS produces when fed via a PCM DAC, ie the DAC 20 trying to send the signal to its onboard DAC for conversion. It is something to be aware of though when running a PCM DAC in an output mode like above. I for eample don’t have this problem as I have my DTS output switched off (I don’t have an AV amp for processing DTS anyway).

All that needs to be highlighted is that when watching DTS encoded material that you take care to always use the 5.1 surround DACs on the AV amp, ie selecting DVD for playback. And not the CD line input as this will feed the DAC 20 PCM DACs attempt at sending the PCM signal.

Think of frying eggs on a red hot skillet with the added joys of a high pitched noise that could break glass that is DTS via a PCM DAC : I was lucky I switched off my source after 3 seconds of this happening.

BTW you dont need a cooling off period, you just nedd to buy er'indoors a pair of Prada or Gucci shoes, trust me on this.

michaelab

Good point about the DTS signal.  Now something else just occured to me which I asked about on the "Amplifiers" forum here but I haven't got a good answer yet (actually someone asked the same question on the HFC forums and he hasn't got a good answer either):

Do AV Receivers generally convert analog input signals to digital (for DSP, Dolby Pro Logic etc processing) and then back to analog?  If this is the case then if I use my AV receiver wouldn't I get the gorgeous DAC20 output mangled again by going through an A/D -> D/A conversion?  My AVR (Marantz SR4200) has a feature called "source direct" which disables all DSP etc but I'm not sure that it's a proper "analog bypass".

I may have to do what ultimately will give me the best sound but leave me with a much more complex system:  use my Arcam Alpha 6  2ch integrated as a power amp for the front 2 speakers (and send the DAC20 analog output directly to it) and use the pre-outs on my AVR to drive the 2 fronts via the Arcam....

Michael.

Nic Rhodes

Whether a receiver digitises a signal or not is down to the individual receiver. Many now days do on some inputs not on others (normally the 5.1 / 7.1 inputs). This actually brings a great point up. For those who want the purest audiophile signal (from you DAC20) may well be best off feeding this stereo signal via the 5.1 inputs. This way you have no distortion issues with subs of HQ stereo signals and the signal is not digitised, goes straight via a volume control to the power amp section. Feeding a stereo signal via a multi channel input might sound daft but if you want the best sound quality……

Re digitisation of analogue signals. Most receivers do this a 20 bit / 96kHz now days, rarely is this 24 bit. People get very worried by the degredations introduced in this process. The reality is it WORKS really well and most can’t tell any difference. Any differences that are heard are generally not associated with the AD process but ‘other’ processing that is taking place. The reason it works so damn well is there is NO SPDIF to muck everything up. The re-digitisation of analogue signals is well down on my list of worries now I have lived with several systems. Beforehand I was worried like yourself.

If you want a DSP to be applied to your stereo signal then re-digitisations needs to take place. Most DAC20 users (substitute you favourite) generally want pure stereo though. If you want to apply say PL2 Music I would by pass the DAC20 and feed a digital signal straight to your receiver.

CJROSS

Michael Im not sure to be perfectly honest, I have always assumed that just using the analogue line inputs on any amp including the SR4200 is an all analogue effort (why does it does it need to be digitally enhnaced again? Thats extra processing which in a lot of cases degrades the signal), now conversely feeding a digital signal into a SR4200 will force the SR4200s DACs to process the signal even with an analogue bypass in place IMO, simple test just have the digital input selected and switch the bypass on/off see if the sound goes on/off or deterioates.

Contact Marantz to see what they say as well. There are guys ehre who know how AV recievers work better than me, One being Beekeeper.

IMHO conencting to the line inputs and listening with anlaogue bypass is the best bet for cD playback, BTW you are indeed correct I think an Arcam 6 will sound superior to the 4200 in hifi terms, again worth a try duder.

michaelab

Unfortunately my SR4200 doesn't have 5.1 inputs   

Just checked the SR4200 specs on the Marantz web site and it DOES do 96kHz/24bit digitisation - so I'm less worried.

I just ordered by DAC20!!!  Unfortunately I won't have a chance to try it out for a couple of weeks as I'm away on business (back in London for 2 weeks).  Will post results here eventually.

Thanks for all the info guys (or should that be dudes? )

Michael.