Finally, an affordable CD Transport: the Shigaclone story

I've never heard a good reason why cables of 1.5 m or longer sound better, but the consensus is that they do. As with all things cable related, if you ask why, you will get 10 different answers from 10 different people and likely none of them make much sense. I didn't ask why, I just got a 1.5 meter cable and moved on.
 
Why 1.5 m minimum, Tibi? :confused:

Digital cable length (from UHF Magazine):
"When a transition is launched into the transmission line, it takes a period of time to propagate or transit to the other end. This propagation time is somewhat slower than the speed of light, usually around 2 nanoseconds per foot, but can be longer… When the transition reaches the end of the transmission line (in the DAC), a reflection can occur that propagates back to the driver in the transport. Small reflections can occur in even well matched systems. When the reflection reaches the driver, it can again be reflected back towards the DAC. This ping-pong effect can sustain itself for several bounces depending on the losses in the cable. It is not unusual to see 3 to 5 of these reflections before they finally decay away. So, how does this affect the jitter? When the first reflection comes back to the DAC, if the transition already in process at the receiver has not completed, the reflection voltage will superimpose itself on the transition voltage, causing the transition to shift in time. The DAC will sample the transition in this time-shifted state and there you have jitter. If the rise-time is 25 nanoseconds and the cable length is 3 feet, then the propagation time is about 6 nanoseconds. Once the transition has arrived at the receiver, the reflection propagates back to the driver (6 nanoseconds) and then the driver reflects this back to the receiver (6 nanoseconds) = 12 nanoseconds). So, as seen at the receiver, 12 nanoseconds after the 25 nanosecond transition started, we have a reflection superimposing on the transition. This is right about the time that the receiver will try to sample the transition, right around 0 volts DC. Not good. Now if the cable had been 1.5 metres, the reflection would have arrived 18 nanoseconds after the 25 nanosecond transition started at the receiver. This is much better because the receiver has likely already sampled the transition by this time."
 
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Digital cable length (from UHF Magazine):
"When a transition is launched into the transmission line, it takes a period of time to propagate or transit to the other end. This propagation time is somewhat slower than the speed of light, usually around 2 nanoseconds per foot, but can be longer… When the transition reaches the end of the transmission line (in the DAC), a reflection can occur that propagates back to the driver in the transport. Small reflections can occur in even well matched systems. When the reflection reaches the driver, it can again be reflected back towards the DAC. This ping-pong effect can sustain itself for several bounces depending on the losses in the cable. It is not unusual to see 3 to 5 of these reflections before they finally decay away. So, how does this affect the jitter? When the first reflection comes back to the DAC, if the transition already in process at the receiver has not completed, the reflection voltage will superimpose itself on the transition voltage, causing the transition to shift in time. The DAC will sample the transition in this time-shifted state and there you have jitter. If the rise-time is 25 nanoseconds and the cable length is 3 feet, then the propagation time is about 6 nanoseconds. Once the transition has arrived at the receiver, the reflection propagates back to the driver (6 nanoseconds) and then the driver reflects this back to the receiver (6 nanoseconds) = 12 nanoseconds). So, as seen at the receiver, 12 nanoseconds after the 25 nanosecond transition started, we have a reflection superimposing on the transition. This is right about the time that the receiver will try to sample the transition, right around 0 volts DC. Not good. Now if the cable had been 1.5 metres, the reflection would have arrived 18 nanoseconds after the 25 nanosecond transition started at the receiver. This is much better because the receiver has likely already sampled the transition by this time."

This is one reason why on a resolute audio system digital cable sounds different from one to another . But not intend to start again the old flame about cables and interconnect so please do not comment on my post here . Thank you.
 
I've never heard a good reason why cables of 1.5 m or longer sound better, but the consensus is that they do. As with all things cable related, if you ask why, you will get 10 different answers from 10 different people and likely none of them make much sense. I didn't ask why, I just got a 1.5 meter cable and moved on.

The one that made sense to me, was that in a 1.5m cable the first signal reflection is delayed enough that by the time it bounces back and reaches the receiver, the original signal has already been sampled, thus minimising "jitter". Longer cable length also has an obvious advantage of attenuating the reflection better (at the expense of adding 1/2 of that attenuation to the original signal, and increasing cable C, L and so on).

See Fred Dieckmann's explanation in this thread: http://www.diyaudio.com/forums/digital-source/12839-digital-cable-length.html

Edit: I see danzup has already posted a similar explanation, while I was checking my resources (and got sidetracked in the process ;)). Well, I'll keep my post anyway, for variety's sake.
 
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To clarify few things about CD puck.
This was made only to offer an alternative to those who are looking for one. Also I had to made one to complete the kit.
There is nothing special about this CD puck except that will fit Sanyo CD mechanic.

Also we are working on a very nice enclosure. I´m sure many of you will be amazed by our design.
Stay tuned.

Regards,
Tibi
 

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