Interconnect with no shield

[Bourneendboy]

I have made a pair up and have to say they are very interesting. I think they do sound very good, but I do have a slight hum at high volume and a louder hum if I touch the cable.
Any ideas on this?

Both my headphone amp and Raspberry Pi/Boss Dac don't have an earth connection at the plug, both mains cables are only 2 core.
Is this causing the hum?
Both the amp and cables are silent with a screened cable.

[anthonyTD]

Try twisting them!

I have made a pair up and have to say they are very interesting. I think they do sound very good, but I do have a slight hum at high volume and a louder hum if I touch the cable.
Any ideas on this?

Both my headphone amp and Raspberry Pi/Boss Dac don't have an earth connection at the plug, both mains cables are only 2 core.
Is this causing the hum?
Both the amp and cables are silent with a screened cable.

[YNWaN]

Yes, I suspect the lack of a mains earth is the reason.

[Stryder5]

Ensure your soldering is good and the plugs are tight in the sockets.

In the past I've had a slight hum through poor plug soldering, touching the cable may be indicating this?

Gary

[Barry]

Despite one's intuitive gut feeling, it is quite possible to use 'twin feeder' or 'twisted pair' style cables and not have hum problems. I have made several, and indeed the use of 300 Ohm ribbon twin feeder aerial cable for audio interconnects was "all the rage" in the mid '80.

The secret is not to have a large area between the two conductors, so common mode interference rejection is not compromised, and the opportunity for magnetic flux linkage is minimal.

The speed of propagation is more down to the dielectric used, and not whether the construction is coaxial or not - even a twin feeder or twisted pair has loop inductance.