Transport Question?

What does a transport actually do? Is it purely a case of reading the 1's and 0's and sending them along a cable or across a circuit board to a D/A converter, or is there alot more to it?
I ask for 2 reasons,

1) because actually I'm quite interested, and

2) I'm now the owner of a Dax Discrete and as this apparently reclocks the signal once the bits have arrived in the Discrete, what actual effect can a transport it's linked to, via ASL actually have?

Cheers
JTB

 

The answer to your question is basically "Yes, that's all it does". As to what difference a transport can make...hmmm....is that Pandora opening her box again? :duck:

Michael.

 

I have it on good authority that with reclocking DACs such as the DAX and DAC64 the transport can make a difference, but not for the expected reasons. The reason is not data integrity or transport jitter, but rather the effect that the transport has on the rest of the system in terms of interference, ie stuff on the mains, radiated, conducted down coax, etc...

Now, if you can find a portable CD player that will run off batteries, and encase it in a copper monolith with an optical connection passing through a waveguide-below-cutoff slot, you should have the perfect transport.... changing discs or batteries could be tricky though.

 

IME, transports can and do make a difference. Se if you can try out a few and decide for yourself.

 

Robbo,

I wish it were that easy, but the AS Discrete benefits hugely from dedicated ASL optical links, which is a £600 touch (and not something you can buy and move from one player to another) and done this way, the signal is reclocked once at the DAC. With that being so, what other variables can there be at the transport to affect the sound. Lets assume the mains are sorted. I'm trying to bottom out whether there really is any need to spend a load on a transport when there's no need.

JTB

 

jtb,
i'm not really sure how asl works but it probably involves a better clock in the transport and some sort of clock link system a-la tag / arcam / cec etc. so that the dac is slaved to the transports clock. it may however do it the opposite way so that the dac's clock is running the transport. of course this is just a guess however if this is the case ususally a reclock will enhance a given transports qualities not radically change them. have a chat to david and see if he has any demo units (or knows of people with units) that you could listen to.
cheers


julian

 

Transports have their own character just like any other component, also the reclocking inside the Discrete won't necessarily clean up a crappy signal.

Over the weekend, thinking I no longer needed it, I took my Meridian 518 out of the chain:

transport->Meridian 568.2->Tact RCS->518->Discrete

What a surprise, the digital output from the Tact RCS sounded totally flat, no width to the soundstage, no sense of rythm, just boring. So it would appear that the Discrete is sensitive to what it's being fed, despite the internal reclocking.

 

I have a marantz ki63 that I use as a transport. I also had a trichord dig turntable, with the posh output board, and clock.

I am sceptical about clocks and jitter, however there was a difference.

Trichords stuff by and large do have a house sound, VERY neutral, slightly bright, and tight bass. A little forward in the mid. with the drums ever so slightly back.

It wasn't any BETTER than the marantz, however, the ki63 has a very distinct character, ever so slightly sibliant, with grumbling bass, and when used as a transport, that still came through.

Now that either means, the transport was dominant,
the analogue stage had the same character.
both transport and analogue together sounded the same.

Why? perhaps the commonality, the circuit layout, the earthing, or the power supply 'colours' the character of the device.

My take on it is error correction is more important, servos, lasers of good quality, for all its hi-techness, the trichord with that digital transmitter was negligibly better.

A transport basically reads the disc, with servo chips to control the laser, all this has to have a dc supply, 18 volts for the motor, and 5 volts for the dig. stuff, so you need a transformer, diodes to make dc from ac, caps. to smoother, and regulators to make it, regular, constant. this is your psu.

you can have 2-3 motors...one to spin the disc, one to open/close the draw, and one to move the laser head, depending on the type.

It then has the clocking circuit to make sure all gets done at the right time, and a display for the info on the disc, this needs a posh chip, too, to make sense of all that info, again needing power, then it gets transmitted to the dac, by a transmitter chip.

The thing that makes me doubt jitter is the marantz has about 600 pico seconds, quite high, the posh clock would make that, maybe 150-200, yet it sounded little better.
Also, the dac64 for all its zero jitter again wasn't a colossal revelation, good, but not the cd destroyer its touted.

 

Data,

Your generalisations are getting more and more gerneral, maybe you need a good base set up from which to make these statements.
I've 6 cdp's and they certainly don't have that house sound, even when switched into the test room at work, prehaps maybe there's something else at work in your system

 

I guess you missed this topic the last time it came round then.

See you in a couple of months...