Mr Steve Posted August 18, 2014 Share Posted August 18, 2014 Hello all, I have acquired some of these boxes. They are marked as OB / OU and have a mic input, output and PA feed output. Inside there is a board with a couple of resistors on and a silver thingy, where all the wires go. Does anyone know what this is, and what it does? http://lightingandsoundservices.co.uk/media/photo.JPG Link to comment Share on other sites More sharing options...
ddproduction Posted August 18, 2014 Share Posted August 18, 2014 Could be a balancing transformer coupled with a mono circuit? Link to comment Share on other sites More sharing options...
dbuckley Posted August 18, 2014 Share Posted August 18, 2014 Mic splitter, transformer isolated. Link to comment Share on other sites More sharing options...
Mr Steve Posted August 18, 2014 Author Share Posted August 18, 2014 Ah yes I see. Thanks! Link to comment Share on other sites More sharing options...
Electrolytic Posted August 18, 2014 Share Posted August 18, 2014 a splitter, OB meaning 'outside broadcast' ? Link to comment Share on other sites More sharing options...
Oldradiohand Posted August 18, 2014 Share Posted August 18, 2014 Looks suspiciously like a classic Beeb eddy box. Yes, the silver thingy is a screened mic transformer. Can't remember what a LL/76/ASC is and my book with the colour codes is in the attic. It's probably a 1:1 600ohm tranny and the box appears to be wired mic in to mic through and then a padded down isolated output., so it's a mic splitter. OU OB might be open university (BBC production base at Milton Keynes) outside broadcast unit - I think they had one. The beeb used mic splitters a lot to isolate phantom feeds and provide electrical safety isolation from other organisations kit. The proper ones have an electrostatic screen between the primary and secondary so this looks like a home brew one. I've made them myself out of old equipment transformers. ......although, bizarrely, the screen seems to be carried through from input to output AND split which certainly wasn't normal practice. Link to comment Share on other sites More sharing options...
Mr Steve Posted August 19, 2014 Author Share Posted August 19, 2014 They are from an old church in MK, actually! Link to comment Share on other sites More sharing options...
alistermorton Posted August 19, 2014 Share Posted August 19, 2014 Milton Keynes .. Open University ... makes sense. Possibly someone doing a bit of scavenging to help out their church a few years go? Link to comment Share on other sites More sharing options...
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