If the DAC is the same, how different do CD transports sound?


One interesting topic of discussion here is how audible the differences are between CD players when they are used as transports only — or when they are only transports to begin with.

In other words, in a comparison which keeps the DAC the same, how much difference can be heard between CD transports?

This recent video by Harley Lovegrove of Pearl Acoustics provides one test of this question. It may not be the ultimate test, but he does describe the experimental conditions and informations about the qualifications of the listeners.

He comes to the main conclusion here: https://youtu.be/TAOLGsS27R0?t=1079

The whole video is worth watching, I think.

128x128hilde45

I dont stream , and i dont use cd transport anymore... Only a battery dac with an internal lossless files bank... Less noise and simpler... I am lucky.. 😊 I transfered all my cd from the last 25 years... I invested in music much more than in my audio system... *I could not do the two...

Interesting thread anyway...

Maybe someone someday can do a deep dive on source to dac issues and come up with some good explanations and examples of what can go wrong. I’m convinced that weird things can go wrong even though the music keeps playing. I’ve heard it myself ; strange and obvious distortion that somehow creeps into the signal chain, and it’s source is in the digital domain. A re-start usually fixes it. I’ve always experienced these anomalies when I’m feeding the digital signal in some kind of daisy chain of devices before it reaches the dac. Some things I think I understand, like when one device is set to 44.1 and another to 48 kHz. You get the playback speed varying all over the place to keep the two devices in sync. Other issues I’ve heard are high distortion, making me think a coil is rubbing. A flute sounds like a kazoo. I’ve also seen video artifacts creep in through fully HDMI connections, where I see a slight ghosting until I unplug and re-plug the HDMI cable. There’s so much processing going on between these devices that opportunities for a corrupt but playable signal can happen.

It will be affected by how clean the digital signal is from the transport to the dac.

 

Most deniers are oblivious to the fact that the “digital signal” going over a wire from transport to dac is an analog signal representing the digital data. Noise on this analog signal caused by a poor transport or bad cable will infiltrate the dac. better dacs can filter some of the noise but filtering is not perfect because electrically everything inside the transport and dac are connected. Nothing is perfect but some equipment and cables are better than others. 

Wanted also to add this factor for transport differences…

 

the optical laser detector inside the transport is an analogue electronics device which is changing its output continuously as the laser light dims and brightens. 
 

Electronics on the pc board later determines if it a 1 or a 0 based on the analog electrical signal from the laser optical reader and sets 1 or 0 based on a threshold. 

Where I am going with this is that another source of electrical noise in the transport is noise that the optical laser detectors is picking up between the high and low points reflections of the CD aluminum pits. This is “light noise” between the high and low reflection signal and is the scattered laser light inside the transport enclosure. 

Everything is connected electrically and better transports will filter this noise from from the optical sensor from getting into the signal path. No filter is perfect but they can reduce noise.

 

this is why darkening the edge of a CD with a marker pen can improve sound reproduction by reducing the scattered light inside the transport which reduces the “light noise”.

 

if you followed this and have a resolving audio system would like to hear back if you can try use a dark marker on a cd edge and listen for differences.

 

I can on my mid level high end system though I mostly stream now.