Hi, I need a rather long audio cable 8 meters or so to connect my desktop DAC to my amplifier. I was thinking of using either a coaxial cable for microphones or a data cable, and making the cable myself.
Out of curiosity, I cut open an old 10-meter HDMI cable that I no longer need. I measured the capacitance between one of the wires and its shielding, it came out to be around 400pF. Is this too high? I’ve read that somewhere between 50-100pF per meter is typically okay.
My questions are:
My HDMI cable has multiple pairs of two wires that are shielded, I was thinkin to pair the two wires for signal and it's shield for each channel, and ground the main shielding maybe the other non pair wires as well to GND.
One wire to it's shielding measure around 380pF and 7ohm. if I parallel them i get around 800pF and 3.5ohm .
Would this HDMI cable work well ? .
Something like this:
Out of curiosity, I cut open an old 10-meter HDMI cable that I no longer need. I measured the capacitance between one of the wires and its shielding, it came out to be around 400pF. Is this too high? I’ve read that somewhere between 50-100pF per meter is typically okay.
My questions are:
- Does the type of cable matter? For example, can I use microphone cables, data cables, or coaxial cables, as long as they are shielded and don’t have excessive capacitance ? . I’m not able to measure the inductance of the cable, but maybe I can calculate it.
My HDMI cable has multiple pairs of two wires that are shielded, I was thinkin to pair the two wires for signal and it's shield for each channel, and ground the main shielding maybe the other non pair wires as well to GND.
One wire to it's shielding measure around 380pF and 7ohm. if I parallel them i get around 800pF and 3.5ohm .
Would this HDMI cable work well ? .
Something like this:
Attachments
I bought two 10m jack to rca cables ( not the cheapest ) and they weren't coaxial, just 4 wires. Now the expensive ones are rather short, I don't know if I can find some good , long cables that won't cost excessively. That's why I would like to make it myself.
I use this type of cables: https://www.tme.eu/ro/katalog/fire-...tor:prolink;lungime-cablu:10m&queryPhrase=rca
I have short (0.5m) for interconnect and long (1.8m). I also use a 5m RCA-Jack 3.5mm.
I chose these after several tests conducted over the past few years, including with cables I made myself.
I have short (0.5m) for interconnect and long (1.8m). I also use a 5m RCA-Jack 3.5mm.
I chose these after several tests conducted over the past few years, including with cables I made myself.
They are very flexible cables and feel good in your hand when you handle them. The connector seems well thought out and has a tiny screw on the side so it seems to be removable. From the looks of it I would say they are coaxial but I can't guarantee this. Maybe I will take the time one day to try to disassemble/open a connector to see exactly what the cable looks like inside.
I also tested other cables from the same place but they were much stiffer and the connector wasn't as secure. I ended up cutting them and saw that they were coaxial but made by a different supplier.
Anyway, at that price I think you can afford to give it a try. They've never caused me any noise problems and the connection is firm without being forced.
I also tested other cables from the same place but they were much stiffer and the connector wasn't as secure. I ended up cutting them and saw that they were coaxial but made by a different supplier.
Anyway, at that price I think you can afford to give it a try. They've never caused me any noise problems and the connection is firm without being forced.
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Anything with a good shield (proper braid) is best for long cables. Capacitance depends on the characteristic impedance of the cable, but why do you want low capacitance - this is going to be driven by an opamp stage in the DAC with 100R in series probably, it won't care about less than 10nF capacitance - that is an issue with MM cartridges and guitar pickups which have high source impedance, not the case here.
Is the DAC output balanced differential? If so the HDMI cable could be useful.
@Mark Tillotson DAC is Fiio new K3 https://www.fiio.com/k3s , ES9038Q2M, OPA1612 for the line out, no, it has balanced only on the 2.5mm jack for headphones. By the way for the headphones amp it says OPA926 I cant find it anywhere.
Picture from the web.
Picture from the web.
