I suspect that my comment in the other thread may be at least partially responsible for this one, so really should post my last couple of efforts!
Note that both of these are in place at FM broadcast sites, so it can't be all bad.
This first one was a modification to an old ex-Radio NZ programme switcher/silence detector, designed to switch between local programming and a network feed, and to turn on a cassette deck for emergency programme when both other sources fail for more than about 14 seconds.
We needed backup programming for when the satellite feed fails (infrequent, but then again we had a 14 hour outage of
Optus B1 about two weeks after installing this).
Rhema gave us this unit which was almost ideal, but desgined for AM and only mono. I decided to leave most of it intact, but add a stereo -10 unbalanced to +4 balanced converter. The left channel of the stereo input is fed into the original mono circuitry to feed the silence detector, and I have tapped into the switching logic to trigger a 4PCO relay to switch between the satellite feed and local programming on cassette.
For I/O I have just replaced the existing 3 pin XLR connectors with 5 pin ones - less destructive than drilling holes, and its easy to revert to the original spec.
Why cassette? Its reliable - 3 hours of quality programming, which doesn't always start at the same point. Rhema are switching to MP3 on their own sites, but on our independently operating ones I'm sticking to cassette. Besides, chrome tape with dbx on a $40 deck from Trademe sounds better than a 128kbps MPEG2 stream off the satellite!
The attached photos show the detail of the new interface (uses 2x TL072s to convert to balanced +4dBm), an overview of the unit, detail of the back showing the new XLRs and the unit safely installed in the rack on-site.
BTW it seems a bit vintage - the 'original' Veroboard was from a sheet we found in my father-in-law's estate about 8 years ago I hadn't used yet, and the BC107 was pulled out of an old ex-TVNZ vision switching control PCB I somehow picked up.