yes I think you mightOriginally posted by michaelab
If you stick a Chord DAC64 (or even a Tag DAC20 like I have) onto the end of an Arcam Alpha 9CD you'll get a very significant improvement.
I am not sure I agree with this. Both of the above products have good / excellent jitter reduction circuits (the Chord being the much better of the two) but jitter is NOT eliminated. There are inherent limitations to what can be done with SPDIF. The best anti jitter solutions eliminate the SPDIF altogether. Tag adopted the sink link for it's players to improve on the PLL solution in their DAC. It is MUCH better. PLL are inherently limited by what they can do but are a double edged sword.Originally posted by michaelab
The jitter issues with SPDIF and outboard DACs can be solved with a good clock recovery DAC. The Tag DAC20 and the Chord DAC64 both fall into this category and make the jitter problems of SPDIF irrelevant. The DAC64 has probably the best solution yet to the problem which is to use a RAM buffer to store the incoming digital stream which can then output the data with absolutely perfect timing - jitter is totally eliminated.
MichaelOriginally posted by michaelab
Also, Yummy Fur, good DACs are pretty transport independent. The difference between a good transport and a bad one is the amount of jitter introduced. Since, as I just mentioned, good DACs can get rid of the jitter then the quality of the transport is not important. Even the cheapest transport will still read the digital data correctly and with a good DAC that's all that matters.
It is a good solution but not perfect. Jitter comes in many different forms, how do you deal with PSU induced jitter. The buffer may overcome many of the SPDIF limitations but this is not the whole story. Much is discussed in the above article.Originally posted by michaelab
Beekeeper, I would suggest that a RAM buffer DAC (like the DAC64) is totally jitter free and transport independent. I don't see how it could be otherwise.
010011101010 are always the same. What about out of band signals saturating input digital receivers, RFI, signal reflections from non standard connectors, ground plains, earths, amplitude, time and frequency domain info?. Dont forget every DVD / CD player has RAM buffers currently, it is just the Chords is bigger than most. Meridian has its FIFO and ROM drives. They still have measurable jitter. It isnt significantly measurably lower than most other methods, just a bit better.Originally posted by michaelab
I hope we agree that any cheapo transport can read the digital data correctly (ie 11001010 will get read as 11001010). Given that, the only issue is jitter. A RAM buffer DAC is effectively reading the digital data and re-recording it into RAM. The RAM buffer is then used as the source. This certainly makes it transport independent and any jitter there is would be what was introduced between the RAM buffer and the actual DAC chip (none I would guess).
RAM buffers are a great solution, dont get me wrong but they are not perfect. What we are essentially describing is a computer. They arent to hot a cd replay from memory are they? Even the best of these (Linn?) is not a patch on their dedicated player. It is not a new solution either, every player has buffers currently, they get too easily confused most of the time! If it eliminates jitter dont you think everyone would be using this wonder techniques rather than just 2 companies?Originally posted by michaelab
Taken to (admittedly ridiculous) extremes a RAM buffer DAC could read the entire CD into memory first and then play it back with the transport switchd off. The digital data stored in memory would be identical regardless of the transport and at the point the transport would be the RAM buffer itself. The DAC64 is just doing this process on a streaming basis but the results should be the same.
PLL are easy to implement, and are reliable but they leave loads to be desired. They do essentially guarantee latching on to signals but additional measures are needed for quality jitter reduction. All your examples are limited by the SPDIF, no wonder they sound similar! Seriously, just reclocking your CD50 will yield MAJOR benefits with the TAG. Look at the Tricord clock3 / Digital Interface Board for REALLY BIG gains. I have done loads of Marantz from this era (inc 50s) and they are simple to do with MASSIVE GAINS. Worth a look IMHO. More info in the long link. I think I might even have an old clock 2 around if that is of any help to you?Originally posted by michaelab
I agree that the Tag DAC20 is not as good as that, and it's PLL cannot eliminate jitter totally but they do a very good job. I've tried my DAC20 with my Marantz CD50SE (my usual transport), a cheapo Pioneer DV-350 DVD player and a Sony Discman portable (via TosLlink) and I could not tell any significant difference between them.
yes, this is why DAC have died a death. It is why Tag are binning off their nice DAC at about £400 as opposed to £1200. Single box solutions eliminates the SPDIF. Both Gary and I use DACs that do NOT use SPDIF ( but can). Instead we use a system that minimises jitter and have probably the lowest jitter of any system on the market. They still have a little jitter but it is really low and even difficult to measure at these levels.Originally posted by katana100
Does a one-box solution avoid the problem of signal degradation between transport and DAC?
Well, they are actually. December's HiFi News reviewed a product called the Sonica from Midiman (www.midiman.co.uk) which basically adds an SPDIF output to any PC or laptop with a USB port.RAM buffers are a great solution, dont get me wrong but they are not perfect. What we are essentially describing is a computer. They arent to hot a cd replay from memory are they?
From the Sonica spec sheet Michael, no mention of any RCA connections, so again my views on the reviewer hearing a difference from his Coaxial output on his S7700 Sony (if he used it that is) comapred to a toslinked connection off the Sonica does fill me with doubt TBH. :Originally posted by michaelab
Well, they are actually. December's HiFi News reviewed a product called the Sonica from Midiman (www.midiman.co.uk) which basically adds an SPDIF output to any PC or laptop with a USB port.
The reviewer (David Allcock) ripped a bunch of CDs to his PC and then "spent numerous hours just enjoying a mix of these various tracks, and being utterly stunned that in every aspect the PC with the Sonica matched my Sony DVP-S7700 transport."
He was using a Perpetual Tech. P-3A Signature DAC. He goes on to say "The Sonica gives you an idea of what Peter McGrath and Ken Kessler heard when playing CDs from a hard drive...with a suitable integrated amp., speakers and a good DAC such as the P-3A or MSB Link DAC you have an easy to use system delivering stunning sound quality and flexibility." (Italics are mine).
I will investigate the Trichord upgrades if they're not too pricey.