SMA connectors -- why not?

[tubetvr]

reading about all the gilt-edge RCA connectors with their lumpy impedance, why not SMA connectors for high-end audio.

Altough I would agree that there are many better connectors then RCA's I wouldn't select SMA's as those are quite fragile, also most SMA connectors are only specified for a mechanical life of 50- 100 connections/disconnections as they wear very quick.

The characteristic impedance of RCA I wouldn't worry about, in a typical audio interface the source is a voltage generator with very low impedance and the receiver is of high impedance which means that reflections are terminated at source and therefore they are not a problem. Even if the system would be made with 50ohm sending amd receiving impedance any imperfections would have almost no effect as the wave length is so much longer then the cable length thereby minimising impact of reflections.

For better audioconnectors there are many alternatives on the market like XLR, mini XLR aso but RCA is de facto standard so it is difficult to change but it is of course possible.

Regards Hans

[jwv3]

Originally posted by tubetvr

I wouldn't select SMA's as those are quite fragile, also most SMA connectors are only specified for a mechanical life of 50- 100 connections/disconnections as they wear very quick.

Regards Hans

I have some various RF devices at work(phase shifters, splitters, mixers, etc) that must have been worn out 20 times over according to that spec. I think it is a bit too conservative, but I also agree they are fragile.

I'd like N connectors on an audio amp. In fact, I think I might like heliax cable interconnects also.

[tubetvr]

I have some various RF devices at work(phase shifters, splitters, mixers, etc) that must have been worn out 20 times over according to that spec. I think it is a bit too conservative, but I also agree they are fragile.

Yes, I said most SMA connectors and then I meant the ones you use for cables, according to manufacturers specifications the mechanical life for these connectors are in the range I wrote.

SMA connectors for LAB equipment are often made of stainless steel or plated with special plating and made for repeated connections but they are much more expensive then ordinary cable connectors.

Regards Hans

[Jax]

Impedance matching at audio frequencies is totally meaningless since the characteristic impedance of a transmission line is frequency dependent.

See link http://home.mira.net/~marcop/ciocahalf.htm

Nothing wrong with SMA connectors, they do their job even at audio frequencies. I would not use them, they are difficult to work with.

RCA connectors can be used at VHF frequencies with good result.