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Transport - does it matter to the sound at all?

I wanted to start this thread, to gain some insight into peoples experiences on this subject.
My view: From the outset of CD and digital media, we were force fed the view that 'its digital so always sounds the same whatever' ideology. Remember the jam on the cd, and it doesn't skip. Since these naive beginning we quickly found out it did matter, and the quality of components, interconnects (its wire isn't it so doesn't affect the sound?) and design DID affect the sound. So I firmly believe that a transport does affect the signal quality and final sound output in a big way. There are transformers, capacitors, boards, wires, all the components that have such a bearing on quality output on all the other components in a system. And the motor, the bearings, the transport mechanism, jitter correction, noise, damping, vibration from itself and speaker interaction ALL will affect the sound.

My question, what are the views on this balance between cost on a DAC and the transport. Are many of us getting it wrong bolting on Sony DVD players to high quality DACs? And are many of the 'quality transports" out there just re-boxed philips units. It does appear very few manufactures build their own transports aka Meridain, Linn and Naim to mention a few.

It would be great to see a high quality transport kit out there, which would allow a full transport and kit DIY project, with mods and part upgrades available at an affordable price.

I haven't the money at present to upgrade my DAC, which is an upgraded Audio Note DAC 1.1 and Zero transport, but I am very happy it at the moment as it was a huge jump over oversampling units I had owned previously.
astrostar59

Showing 8 responses by seandtaylor99

seandtaylor99
1,262 posts
 
From personal experience I believe the single most important issue is jitter. I don't believe that bit errors are a significant source of sonic degradation, or that there's significant performance difference in the area of bit errors.

If you have a well designed reclocking DAC then I think that the transport does not matter. (Think Lavry, and to a lesser extent Benchmark DAC1).

If your DAC derives its clock from the SPDIF, AES EBU, or (horror) toslink input then the transport will matter much more.

I'm pretty certain that your audio note DAC does not reclock the data at all, so I would expect it to be quite sensitive to the transport. If you were to put a quality reclocker in between the transport and DAC, such as a Meridian 518, or a Genesis digital lens, I think you'd find the setup fairly immune to transport quality.
seandtaylor99
1,262 posts
 
The only difference between a good transport and bad transport is jitter.

So you have a choice. Buy a low jitter transport (often very expensive) or buy a reclocking DAC, or a reclocking device to sit before your DAC.

Personally I feel you get much more flexibility from a reclocking device or DAC than an expensive transport, as you can now feed digital signals to it from any transport, from your PC, from a squeezebox, and the sound that comes out will be relatively immune to the quality of the transport.

On the other hand if you buy an expensive transport it will probably sound great, but won't help at all should you ever want to add a squeezebox.

And my final concern is that the transport is generally the least reliable part of digital audio, so I'd rather not spend thousands on it.
seandtaylor99
1,262 posts
 
Steve, the closest to what you suggest "A true re-clocker with good ground isolation" would appear to be the genesis digital lens. (I've never used one, but would like to have a play with one).
seandtaylor99
1,262 posts
 
Thanks for the reply. An additional feature of the Genesis (and the 518, which is a dual PLL, not a true reclocker) is the ability to add dither, and play with the word length. With my limited DSP background dither would appear to be a very interesting possibility, especially since most modern DACs are 18/20 or 24 bit, so the dither can easily be added without reducing the original word length.
seandtaylor99
1,262 posts
 
Zaiks ... the Monarchy is a bad example of a jitter buster. It's priced very competitively, but it either uses a PLL or an ASRC chip to reduce jitter. It does not eliminate the jitter of the transport.

To really eliminate the jitter you need to buffer data to RAM and reclock it with a low jitter oscillator. There's an article about it on the Lavry engineering website.

So it's not surprising that you can hear transport differences with the Monarchy, just as people claim to here differences with transports with the Benchmark DAC1 (also an ASRC).

Alex, you're not the first person to tell me that there are other differences, and also not the first person to not tell what the differences are. If it's a business matter to keep secret then I understand. I would genuinely like to know. It seems unlikely to be bit errors, since a $20 DVD_rom drive can install a bit perfect copy of Windows XP, reading the disk much much faster than a CD would need to be read. (And the OEM purchaser of such a drive can source the main drive components for only a few dollars).
seandtaylor99
1,262 posts
 
JSadurni the benchmark uses an ASRC (asynchronous sample rate convertor) to "remove" jitter. It is well accepted that this method does not remove jitter effectively, and so it does not surprise me that the DAC1 is sensitive to the transport.

"This is high end, we need the best transport and the best DAC with the best reclocking available!!!"

Maybe a brute force and ignorance approach is needed, but I am not convinced that this is the case.
seandtaylor99
1,262 posts
 
Zaikes ... I also use a Monarchy DIP. I wasn't critcizing your choice. It's a great product for the price.

Jsadurni, "brute force and ignorance" is a term for using over-specified products to achieve an end. I was not accusing you of being ignorant.
seandtaylor99
1,262 posts
 
Jsadurni, I certainly don't claim to know the answers to this problem, but here is another DAC manufacturer who says that all transports sound the same, provided they are slaved to an accurate clock in the DAC

http://www.lessloss.com/about.html

And another paper by Dan Lavry, maker of pro-audio DACS (that are very highly regarded)

http://www.lavryengineering.com/white_papers/jitter.pdf

It certainly seems to me that the answer to jitter lies in a properly designed DAC, not in the transport, but I'm always open minded, and if anyone would care to step in with a technical explanation why this is not the case I'd be very pleased for them to do so.
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