Thinking of making a digital coax cable but am struggling to find any decent 75 ohm rca connectors locally. I'd like something a bit better than Jaycar offerings, can someone point me in the right direction?

I'm no digital expert, but when I made my DAC, I gave this some thought:

- '75 ohm' is a so-called 'characteristic impedance' term coined for the nominal impedance only for RF signal transmission (is my understanding). It doesn't mean that the plug connection itself should have 75 ohms impedance.

- RCA connectors were adopted for audio connections, not RF or digital, microwave freqs.

- Whereas RF type connections use shielded (coax cable with centre conductor, surrounded by shield/s) - commonly used standard is the BNC connector (which crimps the shield fully, maintain shielding integrity of the cable into the device). Most RCA plugs do not have this proper design, so they are technically not good digital connectors.

- If you don't want to use BNCs, then I've seen Canare RCAP plugs recommended as a decent 'digital RCA plug - it has a design that crimps & maintains the shield fully around the centre conductor.

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Oh if you're transmitting SPDIF, some have said that, because of the nature of the signal pulses & the frequent possibility of signal reflections at imperfect terminations, then cable length can be important (to avoid signal cancellations) - a figure of 1.5m was suggested as ideal (as opposed to too short, or long).

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Thanks Owen - I have more practical the technical knowledge but understand that impedance is relative to the cable, I guess I should have asked about 75 ohm compatible connectors?

Those RCAP plugs I can only find from Sandman in Wellington, I bought some Canare cable from them a few years ago, good service IIRC. Interestingly they seem to concur with you around digital cable lengths, they have have an article at the bottom of this page.

from memory when home theatre was based around analogue video i recall there was no such thing as a true 75 ohm rca plug ?

fancy stuff like wbt nextgen was rated at 75 ohm but only when used with matching sockets.

most plugs are around 50 ohm.
including those used on high end composite video cables, cables which can double for digital audio.

i've got a bag of them lying somewhere

50 & 75 ohm are RF & video standard nominal impedances - wikipedia

harvey - this was the Steve Nugent article that I read discussing SPdif transmission cable length.

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I only need 1m length but have a couple of older reasonable quality 2m component video cables. One of them can be split to enable the cables to be used separately, I might just do this and see how it sounds.