Looking for a Giant Killer Digital cable

Few things I have learned about digital coax cables:

- BNC connectors are best, but need to get closest to a true 75 ohm RCA connector as possible.

- For cable composition, solid-core is best with silver-plated or pure silver being the desired for digital signals.

- Watch cable length.  I always get 2M / 6 foot digital cables because I have experienced the reflection problems on short cables - this comes across as slightly smeared sound with a loss of resolution.

So, that being said, there are a couple of ideas:

1. Blue Jeans - Beldon 1694A with the Canare RCAP connectors.  It's very cheap at $21 for a 6 foot, but I have been very impressed with this digital cable.  It has beat other cables that were actually a lot more expensive.

2. DH Labs D-750.  A solid-core silver plated conductor with RCA connectors that I think are closest to 75 ohm.  About $200 for 1.5M or $235 for 2M.

I haven't really looked at other cables because I really cannot see spending more than $300 on a coax digital.  But I've thought about building a digital cable using 2 meters of the VH Audio Pulsar Ag silver cable with DH Labs RCA-750 plugs.  This is way down on my priority list because there are many other priorities - and the Beldon 1694A cable performs so well in my systems.

S/PDIF TOSLINK fiberoptic is actually a very horrible cable. The reason is that the LED or light generating source just cannot light up fast enough to transmit the digital square waves properly. It comes across as a very squirly looking wave (not square at all). The result is lost resolution and information - possible problems from signal reflections, ability for target to properly read in the light signals, etc.

Regular S/PDIF COAX digital cable is actually not a bad system, though using BNC connectors is best. Only a true i2s digital connection is better because the DAC/source does not have to encode the stereo digital signals into a single wire signal. That is the S/PDIF method.

Keep in mind that i2s connections will typically use an HDMI cable. This does not mean it’s an HDMI interface. It just uses the cable/connectors as the physical medium for transmitting the i2s signals (which are completely different from normal HDMI audio/video).

Jitter correction really doesn't have anything to do with the length of the cable.  Jitter can be caused by different things, but mostly it is cause by poor clocks or translating audio data back and forth between different digital transmission clock rates.  A good example of this is transmitting S/PDIF over HDMI signal data.  Jitter can also be caused by a "store-and-forward" mechanism of transferring digital data between data bus sections.

The minimum length of cable recommended is generally 1.5M (which is just over 4 1/2 feet).  I always go 6 feet / 2 meter just to be safe.  A short cable can cause reflections.  This happens when the square wave pulse generated at the source hits the target receiver, but the pulse is actually reflected or echoed back down the wire to the source transmitter - which then can cause interference with the next generated pulses (sometimes cancelling out the pulses enough so that it comes across as a NULL pulse).

This doesn't just relate to digital SPDIF coax.  The cable length / reflection issue occurs with all digital cables, including USB and HDMI as well.

There are times where you have a very strong transmitter (such as an HDMI transmitter chip).  I have seen cases where equipment manufacturers actually recommend long HDMI cables.  Sometimes short cables just won't work because of the reflection problems.  Lumagen Radiance video processors is a good example here.

I haven't tried i2s interface.  However, I think the Wireworld HDMI cables are probably the best design overall. 

Many have touted how good USB is and several are of the opinion that USB is the best digital audio connection.  Of course, you can only do DSD audio over USB (or i2s).  In my experience, digital COAX performed much better than USB, but I was just using the USB straight from my motherboard with a poor USB DAC.  I have not tried any of the upgraded USB cards (SOTM, JCAT, Paul Pang).  I'm sure the quality of the USB receiver in the DAC has a lot to do with it as well (the better ones being like Amanero or Singxer).