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Budget DVD player to be used as a transport

Discussion in 'Blu-ray & DVD Players & Recorders' started by Craig, Jan 10, 2005.

  1. Craig

    Craig
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    I am looking at buying an offboard DAC to use together with my Roksan DVD in order to improve the sound quailty

    If I'm happy with the DAC, my next step is to change my DVD player, as I am far from convinced with the Roksan's picture quality*. I am thinking along the lines of a Pioneer (575) or Yamaha model (to match my receiver)

    Therefore, I am targetting a player with

    Good Picture Quality
    Good as possible (at this price :rolleyes: ) transport mechanism

    Having read around, I'm not massively convinced of the need for the lowest jitter level possible, but someone with experience of outboard DAC's might advise......?

    Any ideas, suggestions or comments would be gratefullly accepted :)

    * I only have a 5 year old Panny 32 inch, so I accept I'm not giving it a fair crack of the whip :blush:
     
  2. booktrunk

    booktrunk
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    Pioneers seem to have a good reputation for transports.

    Some good Universal players seem to have the pioneer cheap transports and work from there. Inc some £3k universal players.

    So I would think you couldn't go far wrong with a pioneer 575A as a transport for your DAC.

    Steff
     
  3. bonzobanana

    bonzobanana
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    I'm interested in your not bothered by jitter ratings statement. Why? It was my understanding that digital deviation, i.e. jitter means a fair bit of information is lost with high jitter. Frankly my understanding is that if your just using a dvd player for picture output and bitstream output (coaxial/optical) then your only consideration with regards audio is the digital deviation/jitter rating and you want as low a figure possible in pico seconds. I'm not saying I'm totally clued up here maybe there are other factors.

    I would have thought your ideal player would be an Arcam or Cyrus if your spending serious money but if your on a budget the Limit 'Cyrus tuned' players at play are superb value. There was a review of a Roksan dvd player by What Video and it was just about the worst review I'd seen ever. They really panned it for using a very low end ancient first generation dvd chip that gave very poor results. The review is available for download from this site.
     
  4. Craig

    Craig
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    Having taken a shuftie around the Hi Fi Choice and zeroGain forums, I have been hypnotized by the intense level of debate regarding jitter, those saying (theoretically correct, I guess) that it has a huge impact and others pointing to IRL players that prove that this is not necessarily true.

    Anyway, with a budget of around 150 quid for the player, I've decided - until convinced otherwise - that I won't let it be a primary consideration.

    As for the Roksan, I have been happy enough with the CD replay but more than unsure about the DVD replay....and I think the review for the Roksan DVD player was for the Caspian model, I recall reading and wincing as well ;) .
     
  5. CJROSS

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    http://forum.hifichoice.co.uk/viewtopic.php?t=13633

    Some good reading in here for the audibility of jitter spec (AES paper) and human hearing. Everyone has a different vibe on jitter, does not effect me FWIW.

    Bonzo there is no "information is lost with high jitter" high jitter in transport would cause a breakdown of ther electrical connection or failure to lock onto the signal, there rarely happens in DACs I know of.

    If your on the cheap Tillster, My vibes would be to get the best Pioneer or Toshiba you can lay your hands on, both have very low jitter specs for budget devices if thats a concern. But frankly you better off concentrating on a DAC design thats pretty impervious to jitter effects, the thread above has a mention of a couple highly thought of ones.
     
  6. Craig

    Craig
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    Hi CJ

    My first name's Craig, if that gives it away ;) our path's cross here as well.

    Won't be joining you on zeroGain I'm afraid, that's way out of my league :blush:

    It was that thread in particular that I had read with regard to the effects of jitter !

    (Since this thread, I've bumped into this issue; http://forum.hifichoice.co.uk/viewtopic.php?t=14265 ...... it's the second dumb question further down, regarding inputs / outputs on the DAC)
     
  7. CJROSS

    CJROSS
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    Craig send your AV data down the toslink connection of your DVD player and use the coaxial output of your DVD towards the DAC. It does have both yes ? nearly every DVD-V player on the planet does.
     
  8. bonzobanana

    bonzobanana
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    I'm not sure what you mean, high jitter means small amounts of information are not received so the amp/decoder interpolates to fill in the gaps. If there wasn't a loss of information what would be the problem with jitter? Dolby Digital and DTS are time referenced packets aren't they and not like cd pcm playback which is bitstream to analogue sound conversion. DD and DTS are like a zip file and it is only uncompressed a section at a time and buffered into the audio hardware. Your saying even with jitter that 100% of the binary data is still received and I wouldn't have thought that possible. Maybe I'm wrong but I'm sure I read something along those lines somewhere.

    Also cd players like Arcam and Cyrus are noted for their low jitter ratings and this is often used for the basis for the fine detail they have in their sound output.
     
  9. CJROSS

    CJROSS
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    1) the only gaps that occur in data transfer Bonzo is when error detection on a optical pickup has so many errors (scratches, obscured pits) that it cant fill the gaps in. Nothing to do with jitter. A bit is a bit, its picked up or its not. If not and error detection can interpolate the difference then you hear a skip or missing segment.

    2) Exactly what is the problem witj jitter if there is no loss of data ?, AES don’t think that jitter is audible to very high levels and even then we are talking the levels of a Quad 99 CDPre that measures at 1000 pico sec FYI – now have you seen people waxing lyrical about how good this CD devcie is ?. Just because its measurable picosecs does not mean the human ear can detect it. To cut a quote from the thread I posted to above :

    3) if the jitter is so bad, then some DACs would have trouble locking onto the electrical signal, that does not mean any data is missing from the datastream, its simply means that the connection could not be made due to electrical parameters. Given that we are talking here about sub 1000 spec jitter ie most digital devices known to man with digital outputs and that the most DVD-V transports are @ circa 200-400 then jitter corrupting data is not a concern we should really have. FWIW I use a transport with 40psec of jitter and its makes no difference to another device I have at home that probably measure 10 times that spec or more, proper jitter handling in a DAC negates concerns about jitter, if the DAC designers have any in the first place – see the 47Labs comment above.

    4) Which brings me nicely to the fact that IMHO the most essential part of a DAC is its analogue output stages. No jitter related from transport but when concern is given to the anlg output stages then that’s where DACs/CDPs start to sound different and as the Quad 99 shows high jitter or low jitter personal taste in CD playback is not universally dicated to by jitter.

    There is a large groundswell amongst audiophile on a few hifi boards these days using a non filterless – non oversampling DAC called the NOS DAC from Hong Kong, this has the simplest & rudiementary anti jitter design, ie very simple reclocking, yet people prefere this £100 Homemade DAC over Chord 64, Meridian 507s, etc etc. Now if jitter was such a concern then this DAC would be the first to show it.

    ATB and just some general points on jitter and transports I feel about.
     
  10. bonzobanana

    bonzobanana
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    Interesting, I've read a lot about jitter on many forums and still find conclusions massively varying. As you know many people debate that there is a difference between coaxial and optical yet they are meant to be the same sequence of binary information. As far as I can tell jitter would obviously have much more effect on CD audio playback than DD/DTS and this is probably why low end dvd players are known to have very poor audio cd playback yet the Arcams and Cyrus's are very highly regarded. When you see an audio jitter rating is that an average over minutes of testing and therefore is there an extreme high and low jitter rating? Does jitter in combination with poor reading off dvds results in greater loss of information?

    I'm not technical enough to fully understand the whole process from the laser reading the disc to the electrical signal controlling the speaker cone. I understand the fundamentals but the super technical exact electronic science at every stage of processing is a bit too complicated. However reading forums and looking at reviews of players I have noticed that the high jitter ratings of many dvd players seems to be linked to a speed up of the main dvd drive. What I mean to say is if you buy a cheap chinese dvd player with a chinese brand on often the main dvd drive will run at up to 4x normal dvd speed which will enable fast full motion picture search and very quick acessing on disc plus the layer change pause eliminated. However such players tend to have a more noisy drive obviously and more jitter. I don't know why speeding up the drive produces more jitter. The japanese brand players even the ones made on the cheap in china tend to stick to conventional 1x or sometimes 2x reading. They have slower picture search, more jumpy frame like picture search at higher speed and suffer more from the layer change. However the players run quieter and jitter ratings tend to be lower. The cheap chinese players tend to have if anything better reading of media, less problems with discs. They also have upto 4x the opportunity to re-read the disc in case of a read error.

    The AMW P80L for example has a digital deviation audio jitter rating of 3,000ps but has a superb dvd drive that probably runs at about 4x with good fluid picture search upto very high speeds. Never has problems with media, no layer change and a very good picture via component. Frankly audio cd playback is pants though and can easily be heard by anyone. There is an obvious lack of detail in the music but apart from that nothing unpleasent about it.

    Is this effectively a better dvd transport than something like a Denon which probably is more likely to have a read error or two and has no time to re-read the disc due to its slower dvd drive speed?

    It was my believe that the lower end players with the high jitter ratings were losing a lot of fine detail due to a cocktail of fairly poor timing of the electronics compared to high end stuff.

    I think a lot more blind testing needs to go on, because only then can we really know what the differences are using the end statistics. Technical debate and brand snobbery just takes us away from the reality of our own eyes and ears. Maybe people are wasting their money on top end kit a lot of the time. Maybe you only have to spend serious money if you want top end audio cd playback in addition to DVD playback.

    I'm personally not sure of the significance of jitter especially with regard compressed binary streams. However surely this is something that could be tested 100% because you could create a AC3 music file of binary information store it on a dvd disc and then verify the end binary stream either optical or coaxial was identical. Then it would be known how much loss each player has? It just needs some technical wiz to do this.
     

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