RCA Interconnect Construction Techniques
26/01/12 10:08 Filed in: Cable Construction
This is how I have constructed my “Conventional” interconnect cables.
This technique requires a cable with two "balanced conductors" within a separate shield
- like the DH Labs BL/1 cable or the Van den Hul D102 Mark III
NOTE: ensure the shield is completely insulated from the neutral line and the barrel of the connector
If you want to purchase factory terminated cables there are several companies using this method.
The theory of this technique is that any induced RF/Noise is ONLY flowed back to the "Source Component", away from then next level of amplification. (see Hi-Fi & Grounding)
Note: this requires that the "Source Component" have some type of grounding!
In my hi-fi system, if the source component is not grounded via the power supply, e.g. those with wall-wart power supplies, I have added earth lugs to the case which is connected to a central "ground terminal" on my power distributor - see section on Hi-Fi & Grounding
XLR CONNECTORS:
The same can be accommodated with XLR connectors,
- BUT - the cable must have two or more shields
- ONLY the outer most shield is then connected as shown below
- the inner shield(s) is connected to the ground pin on the XLR connector
2. I wanted to increase the diameter of the teflon tube, so I added a piece of expandable nylon sleeving
3. Secure the sleeve with a piece of heat-shrink tubing
4. remove one twisted pair of conductors from a length of CAT6 network cable
Using a wooden dowel 5mm or 6mm in diameter, tape one end of the CAT6 and then twist the conductor around the dowel
5. Insert the teflon tube with the sleeve into the helix
6. Strip 4mm - 5mm of the insulation from both CAT6 wires, twist together and solder
7. At the other end of the assembly,
8. Tighten the CAT6 helix wire around the tube assembly and secure with a piece of Heat-shrink tubing
9. Insert the signal conductor into the Teflon Tube assembly, cut to length and strip 4-5mm of insulation
10. Insert the cable assembly into a piece of expandable nylon tubing of your choice for finishing and secure with a piece of Heat-shrink tubing
11. Attach RCA connectors of your choice - plug in and play
**OK - remember that unconnected wire?
Why is it there? What does it do?
So how does this architecture work?
There are two type of noise that this architecture guards against
For induced noise between conductors to be an issue the conductors need to be in parallel and in very close proximity - as in many conventional Interconnects.
RFI, being due to external influences, is a little trickier to guard against, but basically it effects a length of “unprotected” conductor - e.g. an antenna
For the very best performance I recommend using any of the KLE Innovations Harmony Plug range of products
Why don’t more cable manufacturers use this architecture?
That’s it - hope your DIY cables perform as good as my own
MK-II Helix Interconnect Upgrade
This upgrade applies to the Helix Interconnect detailed above.
The only modification applies to the Neutral conductors - two twisted pairs are now used for the neutral conductor
In the photo below I’ve paired the Orange and Brown twisted pairs and the Blue and Green twisted pairs for the second cable
The benefits of adding a second twisted pair to the neutral include
An unexpected benefit - the interconnect can now be used as a high resolution SPDIF interconnect, which I’ve tested up to 24/192 resolution
MK-III Helix Interconnect Upgrade
This upgrade applies to the Helix Interconnect MK-II detailed above.
The only modification applies to the Neutral conductors again - three twisted pairs are now used for the neutral conductor
The benefits of adding a third twisted pair to the neutral include
Better Digital Interconnect performance - warmer more analogue like reproduction, which I’ve tested up to 24/192 resolution
Digital CAT6 S/PDIF Construction Details
The following details how to construct the CAT6 S/PDIF cables I currently use
This S/PDIF cable is made from a single piece of regular CAT6 Cable
At one end of the cable
At the other end of the cable
I use a piece of heat-shrink to identify which RCA is to be connected to the grounded component
If desired you can insert the cable into expandable nylon sleeve for a much nicer, more professional look
The solid coloured wires that are not attached at one end of the cable provides similar benefits as the floating shield techniques above.
KLE Innovations Harmony RCA Plugs are required for this cable to work!
I use KLEI Absolute Harmony RCA’s for ultimate performance!
I have built a 1/2 meter and a 2 meter cables using this technique and I cannot tell the difference between the two cables
They are extremely detailed and work well up to 24/192 sample rates - and maybe beyond
UPDATE:
I’ve read a few posts on various forums as to why certain people feel that either the CAT6 or helix designs above will NOT work for digital interconnects.
Conventional wisdom cites that for the most successful transmission of digital signals one must use 50, 75 or 110 ohm cables with identically matching connectors
This is true and the main reason as to why so many DIY cables tend to fail - the RCA used is of a lower impedance than the cable. Intact, most RCA’s have a significantly lower impedance than even 50 ohm.
However, a “new wisdom” has identified that as long as the impedance of the connector is higher than the impedance of the cable, the destructive artifacts normally associated with a cable having connectors of a lower impedance, are also prevented
Why do my cables work???
The Digital CAT6 cable identified above uses 100 ohm CAT6 and the impedance of the KLEI RCA’s is higher than 110 ohm - and since the quality of copper used in CAT6 is designed specifically for digital transfers - they tend to work very very well.
As for the Helix Design Interconnect - it’s impedance would appear to be lower than the KLEI RCA’s because there is no indication of those destructive digital artifacts present in them either.
Their use of a silver signal conductor and helix neutral conductor aid signal transfer and does a significantly better job of transferring a more complete digital signal - it works even better than the CAT6 design.
Are they the best digital interconnects in the world - that would be the KLEI gZero 3D - however - they are extremely “cost effective”
OH YES! - they also perform significantly better than most 75 ohm coax designs from many well known brand names
BUT - you do need to use the KLEI RCA’s - normal RCA’s or even 75 ohm RCA’s will NOT be as effective
This technique requires a cable with two "balanced conductors" within a separate shield
- like the DH Labs BL/1 cable or the Van den Hul D102 Mark III
NOTE: ensure the shield is completely insulated from the neutral line and the barrel of the connector
If you want to purchase factory terminated cables there are several companies using this method.
The theory of this technique is that any induced RF/Noise is ONLY flowed back to the "Source Component", away from then next level of amplification. (see Hi-Fi & Grounding)
Note: this requires that the "Source Component" have some type of grounding!
In my hi-fi system, if the source component is not grounded via the power supply, e.g. those with wall-wart power supplies, I have added earth lugs to the case which is connected to a central "ground terminal" on my power distributor - see section on Hi-Fi & Grounding
XLR CONNECTORS:
The same can be accommodated with XLR connectors,
- BUT - the cable must have two or more shields
- ONLY the outer most shield is then connected as shown below
- the inner shield(s) is connected to the ground pin on the XLR connector
Helix Interconnect Construction Details
The following details how to construct the Helix DIY Interconnect cables I currently use
1. I start with a piece of teflon tube - this one had an external diameter of 3.0mm and an internal diameter of 2.5 mm
- A larger outside diameter can be used - 4mm to 5mm would be ideal and eliminate the need for steps 2 and 3
- caution: do not use really thick tubing, because it reduces overall cable flexibility and tight radius bends will result in the tube collapsing
2. I wanted to increase the diameter of the teflon tube, so I added a piece of expandable nylon sleeving
3. Secure the sleeve with a piece of heat-shrink tubing
4. remove one twisted pair of conductors from a length of CAT6 network cable
- for interconnects I use a ratio of 3:1 neutral:signal conductor, e.g.
- for a 3 ft interconnect I would use 9ft of CAT6
- for a 6 ft interconnect I would use 18 ft of CAT6
Using a wooden dowel 5mm or 6mm in diameter, tape one end of the CAT6 and then twist the conductor around the dowel
- CAT6 is stiff enough to retain the helix shape once tension is released
5. Insert the teflon tube with the sleeve into the helix
6. Strip 4mm - 5mm of the insulation from both CAT6 wires, twist together and solder
- Secure the end with heat-shrink tubing
7. At the other end of the assembly,
- untwist the CAT6 wires for 1.25 inches (30mm)
- cut 1.0 inch off of one of the wires
- Strip 4-5mm of insulation from the longer of the two wires only - this is the actual neutral conductor
- the shorter wire will not be connected at this end
- see **OK - remember that unconnected wire? below for an explanation.
8. Tighten the CAT6 helix wire around the tube assembly and secure with a piece of Heat-shrink tubing
9. Insert the signal conductor into the Teflon Tube assembly, cut to length and strip 4-5mm of insulation
- the material the signal conductor is made from is your choice
- for a “budget cable” OR “proof of concept” prototype, a single strand of CAT6 can be used
- even CAT6 performs extremely well - the cable architecture is responsible for much of the excellent performance characteristics of this intrconnect
- My cables use a 24 gauge solid silver strand for the signal conductor which provides many additional benefits.
10. Insert the cable assembly into a piece of expandable nylon tubing of your choice for finishing and secure with a piece of Heat-shrink tubing
11. Attach RCA connectors of your choice - plug in and play
**OK - remember that unconnected wire?
Why is it there? What does it do?
- This cable is designed to minimize RFI/EMI noise that may be induced into the various conductors
- For best effect - it should always be connected in one direction
- The end that had both CAT6 wires stripped and twisted together should always be connected to the source component
- that unconnected wire interrupts the induction of noise into the neutral wire
- connecting it to the neutral of the source component simply provides a single connection to “ground”
- This is a similar feature of the “Floating Shield” concept as detailed at the beginning of this section
- One end of the cable should be marked in some manner
- I place a piece of Heat-shrink around the barrel of the RCA that should be connected to the source component
So how does this architecture work?
There are two type of noise that this architecture guards against
- Induced Noise between signal and neutral conductors caused by Electromagnetic Interference - (EMI)
- Induced noise from external sources due to Radio Frequency Interference (RFI)
For induced noise between conductors to be an issue the conductors need to be in parallel and in very close proximity - as in many conventional Interconnects.
- Twisting the neutral conductor around the signal conductor eliminates parallel conductors since the neutral is almost at a 90 degree angle to the signal conductor - minimizing the effect of EMI induced noise
- Having a teflon tube also puts a little distance between the neutral and signal conductors, reducing the effect of induction even further
RFI, being due to external influences, is a little trickier to guard against, but basically it effects a length of “unprotected” conductor - e.g. an antenna
- The signal conductor is the main issue here - we want the signal to be noise free
- Winding the neutral conductor around the signal conductor “interrupts” the effect of RFI - much like a conventional shield
- Twisting the two wires of the neutral conductor effectively “interrupts” the effect of RFI on the neutral conductor, with any residual interference being transferred to “earth” via the that floating wire attached to the source component
For the very best performance I recommend using any of the KLE Innovations Harmony Plug range of products
Why don’t more cable manufacturers use this architecture?
- It has to be constructed by hand
- It takes twice as much wire as conventional Interconnects
That’s it - hope your DIY cables perform as good as my own
MK-II Helix Interconnect Upgrade
This upgrade applies to the Helix Interconnect detailed above.
The only modification applies to the Neutral conductors - two twisted pairs are now used for the neutral conductor
- at one end all four wires are attached to the neutral pin of the RCA
- at the other end the solid coloured wires are trimmed back leaving only the striped wires connected to the neutral
In the photo below I’ve paired the Orange and Brown twisted pairs and the Blue and Green twisted pairs for the second cable
The benefits of adding a second twisted pair to the neutral include
- Improved clarity with finer details
- improved image focus
- faster dynamic response
- warmer more complete sound
An unexpected benefit - the interconnect can now be used as a high resolution SPDIF interconnect, which I’ve tested up to 24/192 resolution
MK-III Helix Interconnect Upgrade
This upgrade applies to the Helix Interconnect MK-II detailed above.
The only modification applies to the Neutral conductors again - three twisted pairs are now used for the neutral conductor
- at one end all six wires are attached to the neutral pin of the RCA
- at the other end the solid coloured wires are trimmed back leaving only the striped wires connected to the neutral
The benefits of adding a third twisted pair to the neutral include
- Improved clarity with finer details
- improved reproduction of very fine venue acoustics
- much nicer vocal textures
- lower noise floor
Better Digital Interconnect performance - warmer more analogue like reproduction, which I’ve tested up to 24/192 resolution
Digital CAT6 S/PDIF Construction Details
The following details how to construct the CAT6 S/PDIF cables I currently use
This S/PDIF cable is made from a single piece of regular CAT6 Cable
At one end of the cable
- Strip and solder the BLUE wire to the signal pin of the RCA
- Then strip and solder the all remaining wires to the ground pin of the RCA
- This end of the cable must be connected to a component that is grounded
At the other end of the cable
- Strip and solder the BLUE wire to the signal pin of the RCA
- Then cut back the solid colour wires (green, Brown and Orange) back to the sleeve
- These wire are not attached at this end (see below)
- Then strip and solder all remaining wires with coloured stripes to the neutral pin of the RCA
I use a piece of heat-shrink to identify which RCA is to be connected to the grounded component
If desired you can insert the cable into expandable nylon sleeve for a much nicer, more professional look
The solid coloured wires that are not attached at one end of the cable provides similar benefits as the floating shield techniques above.
KLE Innovations Harmony RCA Plugs are required for this cable to work!
I use KLEI Absolute Harmony RCA’s for ultimate performance!
I have built a 1/2 meter and a 2 meter cables using this technique and I cannot tell the difference between the two cables
They are extremely detailed and work well up to 24/192 sample rates - and maybe beyond
UPDATE:
I’ve read a few posts on various forums as to why certain people feel that either the CAT6 or helix designs above will NOT work for digital interconnects.
Conventional wisdom cites that for the most successful transmission of digital signals one must use 50, 75 or 110 ohm cables with identically matching connectors
This is true and the main reason as to why so many DIY cables tend to fail - the RCA used is of a lower impedance than the cable. Intact, most RCA’s have a significantly lower impedance than even 50 ohm.
However, a “new wisdom” has identified that as long as the impedance of the connector is higher than the impedance of the cable, the destructive artifacts normally associated with a cable having connectors of a lower impedance, are also prevented
Why do my cables work???
The Digital CAT6 cable identified above uses 100 ohm CAT6 and the impedance of the KLEI RCA’s is higher than 110 ohm - and since the quality of copper used in CAT6 is designed specifically for digital transfers - they tend to work very very well.
As for the Helix Design Interconnect - it’s impedance would appear to be lower than the KLEI RCA’s because there is no indication of those destructive digital artifacts present in them either.
Their use of a silver signal conductor and helix neutral conductor aid signal transfer and does a significantly better job of transferring a more complete digital signal - it works even better than the CAT6 design.
Are they the best digital interconnects in the world - that would be the KLEI gZero 3D - however - they are extremely “cost effective”
OH YES! - they also perform significantly better than most 75 ohm coax designs from many well known brand names
BUT - you do need to use the KLEI RCA’s - normal RCA’s or even 75 ohm RCA’s will NOT be as effective