This monstrosity should be illegal in audio!
Some primitive tribes believe that the past is the source of all wisdom and somehow we have lost that wisdom over the ages. That would account for the popularity of vintage audio equipment then!
No seriously, there is a lot of good equipment from the past, but that isn't to say that everything that is old in audio is good.
One thing that is certainly far from good is the RCA jack connector, also known as the phono (for phonograph, apparently) connector or cinch connector.
This connector dates back to the 1940's and clearly is the work of an apprentice engineer late on a Friday afternoon. Perhaps it was a practice project.
How it ever came to be so popular is a mystery. The only thing going for it is its compact size.
So what's wrong with it then?
Simple, and it's a big thing - this connector is not and cannot be balanced. Balanced audio means that the signal is carried on two conductors enclosed in a screen.
In a phono cable, there is only one conductor, and the screen must form part of the audio circuit. Duh? The screen is there to mop up interference, and you're using it to carry audio? Yes indeed, sad but true.
One pleasure of working with pro equipment is that it is universally balanced. With balanced audio, you just connect everything together and get to work. With unbalanced systems, you play hunt the buzz, where's the crackle, oh dear we'll just have to put up with it...
And balanced wiring is so simple.
The problem with balanced wiring is that it requires an XLR connector, or a 3-pole jack, both of which are comparatively bulky connectors.
What the world desperately needs is a small three-pole connector suitable for a balanced signal. We really do need that, then everything in our semi-pro studios can be balanced and our lives will be hum and interference free.
Is there anything else wrong with the RCA jack?
Yes, the earth connects last, after the signal pin. You are likely to get a massive hum as you insert it, only momentarily, but it really should not happen. In a properly designed XLR connector, the earth connects first, as it should, therefore the connection is protected even before it is fully made.
And phono connectors, despite improvements in recent years, are still damned fiddly to solder.
Shall we start a campaign for a new audio connector? It's about time someone did.