The Secret Society of Lathe Trolls

Jason W. · Joined: 14 Feb 2007 Posts: 2

Hello. I just stumbled upon this site while trying to find information about the Meissner Radio Phono Recorder (9-1065). A friend and I are trying to get one up and running that he found at an antique store, but unfortunately the original microphone doesn’t work. Can anyone please tell me if I can buy an adapter for an xlr input into the machine, and if so, where to look?

Thanks…

cuttercollector · Joined: 11 Jun 2006 Posts: 286 Location: San Jose, CA

The original connector used on these is an obscure 3 or 4 pin Amphenol connector. I don't even know the type name. This is an unbalanced high impedance mic or line level input which is not directly electrically or physically compatible with an xlr type connector or signal.
According to the manual pin 1 is ground, pin 2 is hot mic level direct to grid of the mic preamp tube, pin 3 is high level (line) hot through a coupling capacitor. There were units with a 4 pin socket, in which case pin 4 is blank - no connection. Some people replaced these with standard 1/4'' phone jacks wired however they wanted. There are 2 jacks with their own seperate input levels (2 input mixer) and a switch to switch between high gain (low level or mic) and low gain ( high level or line).
What I would do is wire one of those plugs with a home made adaptor as follows, pin 2 to the tip of a 1/4" inline jack, pin 3 to the tip of an inline RCA phono jack using short lengths of standard patch cable type shielded wire, ground the sleeve (shield) of both the phono jack and the phone jack to pin one of the Meissner 3 pin plug. Now, just plug line level sources into the phono jack and high impedance unbalanced mics into the 1/4" jack. Use a standard 1/4" male high impedance out from XLR low impedance balanced input type external mic transformer to connect a modern low impedance balanced microphone. Use the unit's own selector to switch between mic or line gain settings. That should all work reasonably well with modern input sources

cuttercollector · Joined: 11 Jun 2006 Posts: 286 Location: San Jose, CA

I did a little more research with an old electronics parts catalog and the connectors are probably NOT Amphenol. They did make 3 & 4 pin connectors but not the same.
I think the most likely thing they could be is a Cinch-Jones 5K3 (or 5K4 for the 4pin) so called "battery plug". This is just the bare plug, the metal shell looks like the picture of an 18G, though it says that is for the female socket part called a 6K3.
I could be entirely off on this as I have seen some similar looking connectors that were not quite the same size.
If the mic you have is not working and you only want to use 1 input to test you could just steal it's plug.
BTW, if the mic looks like a round ball on the end of a short tube on a little desk stand DON'T toss it out. Those are really rare mics!

Jason W. · Joined: 14 Feb 2007 Posts: 2

Thanks cuttercollector, much appreciated!