DIY "Audiophile" Digital Coax cable

[Amarendra]

Hi

After DIY speaker, power and RCA cables, I thought of building my own digital coax cable. For this I sourced the cable from The Audio Co. Its a Furutech Cable (see snaps). Surprisingly the inner copper is not a single solid copper wire but a bunch of copper strands. Cable retails for INR 800/ metre.

For terminations I decided to try Aucharm solderless RCA plugs. These plugs were sourced from TheAudioCrafts @ INR 800 +150 per pair. See snaps.


This was supposed to be quite a simple exercise but I realized that the Aucharm plugs were slightly big for the wire. So i had to use some padding from the outer insulation to pack it.



Listening tests/conclusion:
The Aucharm RCA has a very strange construction. Besides being too large, the outer blue casing / covering is too close to the actual end terminal. The result is that it can't go into the coax out of the WiiM media player where the Coax Out is slightly recessed into the box of the media player. So I had to remove the blue cover from that terminal.

This Furutech cable replaced a free SPDIF cable. So the switch was not only from SPDIF to Coax but also from a free unbranded cable to a branded cable.
I found a slight difference in sound. Thinking that I was biased, I played a few songs for my daughter who mentioned that some instruments which were usually not noticed earlier (too soft earlier?) could be heard and it felt like the singer was taking more time to sing (more space perhaps ?)

If you have suggestions for solderless RCA plugs please share.

Thanks for reading. As always suggestions welcome.

 

[reignofchaos]

These plugs are not 75 ohm. They are meant for analog interconnects. You better replace them else you are losing signal integrity.

 

[mbhangui]

These plugs are not 75 ohm. They are meant for analog interconnects. You better replace them else you are losing signal integrity.

I think it doesn't matter because most likely the wiim pro has a RCA socket for the digital out and hence it is already a lost cause.

Is There Such a Thing as a 75 Ohm RCA Plug? -- Blue Jeans Cable

 

[reignofchaos]

I think it doesn't matter because most likely the wiim pro has a RCA socket for the digital out and hence it is already a lost cause.

Is There Such a Thing as a 75 Ohm RCA Plug? -- Blue Jeans Cable

No idea about the connector on the device but canare is an inexpensive plug that is close to 75 ohm on RCA. The alternative is eichmann bullet 75 ohm version but this is expensive.

 

[IndianEars]

This 75 Ohms impedance for the SPDIF is a rats nest

 

[reignofchaos]

This 75 Ohms impedance for the SPDIF is a rats nest

Yes agree - if only all devices had bnc, it would be so much easier.

 

[keith_correa]

Then you need to buy the Canare crimp tool for the RCAP and the appropriate crimp die and soon, it all goes south!

 

[Amarendra]

Then you need to buy the Canare crimp tool for the RCAP and the appropriate crimp die and soon, it all goes south!

Then buying a ready made "audiophile" cable becomes more economical

 

[Amarendra]

These plugs are not 75 ohm. They are meant for analog interconnects. You better replace them else you are losing signal integrity.

Thanks for sharing. I will read about it

 

[Amarendra]

Has anyone tried this and can it distort the signal ?

 

[keith_correa]

Has anyone tried this and can it distort the signal ?
View attachment 84199

Tried it. Works as intended and as it should. Why would it distort the signal?

 

[Amarendra]

Tried it. Works as intended and as it should. Why would it distort the signal?

Because its cheap, not gold plated and not from a world- famous company like Audioquest.

 

[IndianEars]

Has anyone tried this and can it distort the signal ?
View attachment 84199

To answer your questions ... and provide an explanation:

1. Yes, I have tried these connectors. They are Not meant for use at High Frequencies (eg the type used for SPDIF signals)
These connecters are Complete "Phoo-Phoo" for SPDIF and Digital Clock Signals

2. Yes, they WILL Distort the SPDIF signal. (More on that later)

3. A Basic brief on Cable Impedance.
A CoAxial cable (the type used in a Digital Coax cable) is as shown in this pic by you, Amarendra



The Impedance of tis cable depends on:
1. The Material of the dielectric... which is the white plastic between the Centre Copper wire & the outer copper braiding ("jali")
2. The material & Diameter of the conductors
3. The diameter of the dielectric i.e. (constant) distance separating the Centre Wire & the Braiding. Note that the Braid Completely Envelopes the centre conductor

To maintain its 75 Ohm Impedance, the distance separating the Centre Wire & the Braiding MUST REMAIN CONSTANT THROUGHOUT THE CABLE + CONNECTOR ASSEMBLY.

The green & black connectors do not maintain
a. The Constant Distance
b. The outer braid does not completely cover / envelope the centre conductor. It runs alongside , where the 2 screws are located!

Hence 75 Ohm impedance is thrown out of the window, for any Coaxial cable using these connectors.

Since the impedance is not maintained at the required 75 Ohms impedance, the Signal Will Be Distorted.
This distortion will not be dramatic, particularly on a less revealing (usually budget priced) system.

The Million Dollar questions:
x. Is the distortion audible?
y. Is the distortion euphonic? Do you actually prefer the euphonic sound?
Both the above: x & y are upto you and your system.

I would urge you to even try any analog interconnects for SPDIF signals, and even Cheap RCA to RCA Cables that are typically bundled free with DVD Player.
They will all work and provide a different sonic signature. If you like it ...... you can use them. They will not damage your Audio Components.

Sadly, "Cable Impedance" & "System Impedance" is rarely well understood (Even though it can be explained quite simply), and lots of misconceptions prevail.



There has already been a relevant discussion on this topic here on this very forum, in 2021. Do check it out.

 

[Yelamanchili manohar]

I would urge you to even try any analog interconnects for SPDIF signals, and even Cheap RCA to RCA Cables that are typically bundled free with DVD Player.
They will all work and provide a different sonic signature. If you like it ...... you can use them. They will not damage your Audio Components.

I have 2 pairs of hifidelity HT-CR1 RCA cables and one coaxial digital. They all look exactly the same. So when I got the coaxial, I wrapped a rubber band around it and kept it in my cables box.

One day my daughter needed a rubber band to tie up her barbie's hair, and took this rubber band. It's been 3 years, and trying to separate that coaxial from the RCA's has become the obsession of my life.

 

[Amarendra]

To answer your questions ... and provide an explanation:

1. Yes, I have tried these connectors. They are Not meant for use at High Frequencies (eg the type used for SPDIF signals)
These connecters are Complete "Phoo-Phoo" for SPDIF and Digital Clock Signals

2. Yes, they WILL Distort the SPDIF signal. (More on that later)

3. A Basic brief on Cable Impedance.
A CoAxial cable (the type used in a Digital Coax cable) is as shown in this pic by you, Amarendra

View attachment 84209

The Impedance of tis cable depends on:
1. The Material of the dielectric... which is the white plastic between the Centre Copper wire & the outer copper braiding ("jali")
2. The material & Diameter of the conductors
3. The diameter of the dielectric i.e. (constant) distance separating the Centre Wire & the Braiding. Note that the Braid Completely Envelopes the centre conductor

To maintain its 75 Ohm Impedance, the distance separating the Centre Wire & the Braiding MUST REMAIN CONSTANT THROUGHOUT THE CABLE + CONNECTOR ASSEMBLY.

The green & black connectors do not maintain
a. The Constant Distance
b. The outer braid does not completely cover / envelope the centre conductor. It runs alongside , where the 2 screws are located!

Hence 75 Ohm impedance is thrown out of the window, for any Coaxial cable using these connectors.

Since the impedance is not maintained at the required 75 Ohms impedance, the Signal Will Be Distorted.
This distortion will not be dramatic, particularly on a less revealing (usually budget priced) system.

The Million Dollar questions:
x. Is the distortion audible?
y. Is the distortion euphonic? Do you actually prefer the euphonic sound?
Both the above: x & y are upto you and your system.

I would urge you to even try any analog interconnects for SPDIF signals, and even Cheap RCA to RCA Cables that are typically bundled free with DVD Player.
They will all work and provide a different sonic signature. If you like it ...... you can use them. They will not damage your Audio Components.

Sadly, "Cable Impedance" & "System Impedance" is rarely well understood (Even though it can be explained quite simply), and lots of misconceptions prevail.



There has already been a relevant discussion on this topic here on this very forum, in 2021. Do check it out.

Thanks !! I have ordered the cheap connectors and will experiment over the weekend.

 

[Amarendra]

To answer your questions ... and provide an explanation:

1. Yes, I have tried these connectors. They are Not meant for use at High Frequencies (eg the type used for SPDIF signals)
These connecters are Complete "Phoo-Phoo" for SPDIF and Digital Clock Signals

2. Yes, they WILL Distort the SPDIF signal. (More on that later)

3. A Basic brief on Cable Impedance.
A CoAxial cable (the type used in a Digital Coax cable) is as shown in this pic by you, Amarendra

View attachment 84209

The Impedance of tis cable depends on:
1. The Material of the dielectric... which is the white plastic between the Centre Copper wire & the outer copper braiding ("jali")
2. The material & Diameter of the conductors
3. The diameter of the dielectric i.e. (constant) distance separating the Centre Wire & the Braiding. Note that the Braid Completely Envelopes the centre conductor

To maintain its 75 Ohm Impedance, the distance separating the Centre Wire & the Braiding MUST REMAIN CONSTANT THROUGHOUT THE CABLE + CONNECTOR ASSEMBLY.

The green & black connectors do not maintain
a. The Constant Distance
b. The outer braid does not completely cover / envelope the centre conductor. It runs alongside , where the 2 screws are located!

Hence 75 Ohm impedance is thrown out of the window, for any Coaxial cable using these connectors.

Since the impedance is not maintained at the required 75 Ohms impedance, the Signal Will Be Distorted.
This distortion will not be dramatic, particularly on a less revealing (usually budget priced) system.

The Million Dollar questions:
x. Is the distortion audible?
y. Is the distortion euphonic? Do you actually prefer the euphonic sound?
Both the above: x & y are upto you and your system.

I would urge you to even try any analog interconnects for SPDIF signals, and even Cheap RCA to RCA Cables that are typically bundled free with DVD Player.
They will all work and provide a different sonic signature. If you like it ...... you can use them. They will not damage your Audio Components.

Sadly, "Cable Impedance" & "System Impedance" is rarely well understood (Even though it can be explained quite simply), and lots of misconceptions prevail.



There has already been a relevant discussion on this topic here on this very forum, in 2021. Do check it out.

From what I understand these cheap connectors should be more palatable in an analog RCA cable - such as the one between DAC and amplifier ?

 

[Kannan]

From what I understand these cheap connectors should be more palatable in an analog RCA cable - such as the one between DAC and amplifier ?

take care while terminating Balun connectors, you can easily end up with a short. Heat shrink each core (even so if core and shield).

 

[IndianEars]

From what I understand these cheap connectors should be more palatable in an analog RCA cable - such as the one between DAC and amplifier ?

Ideally, they should be used for low voltage power, such as 5 Volts or 12 Volts from a wall wart.

Yes, such RCAs can also be used as compromised connectors for non demanding audio use

 

[Amarendra]

Ideally, they should be used for low voltage power, such as 5 Volts or 12 Volts from a wall wart.

Yes, such RCAs can also be used as compromised connectors for non demanding audio use

What is the compromised part in these connectors ? You explained for digital connection but what’s the compromise in analog signals ?

 

[IndianEars]

In a single word .... "shielding'

The woven braid and / or foil tape no longer envelopes the inner conductor of the cable.

That probably also holds true for the signal path inside the RCA connector with side-by-side screw terminals.