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Author Topic: Can stereo reverse reader be hooked to mono system? Brad Allen Jedi Master Film Handler Posts: 688 From: Evansville, IN, USA Registered: May 2000 posted 01-05-2004 03:58 PM                     I need to temporarily hook the output from a stereo reverse scan reader to a mono system. Can this be done without problems? If so, any tips greatly appreciated. Thanks  |  IP: Logged John Anastasio Master Film Handler Posts: 325 From: Trenton, NJ, USA Registered: Sep 2000 posted 01-05-2004 05:37 PM                        I can't imagine any problems as long as you keep both channels in phase.  |  IP: Logged Sam D. Chavez Film God Posts: 2153 From: Martinez, CA USA Registered: Aug 2003 posted 01-05-2004 08:45 PM                       Reverse scan readers can be hooked to mono systems but there are some gotchas. Most mono systems have some sort of 50 Ohm or so input loading resistor meant to swamp the solar cell in order to obtain flat frequency response. Sometimes it is the mono system's volume control that forms the load. If not removed, there is very little signal from the output of the reader so you will end up running the mono system wide open. You may also run into some grounding issues, every case is different.  |  IP: Logged John Anastasio Master Film Handler Posts: 325 From: Trenton, NJ, USA Registered: Sep 2000 posted 01-07-2004 06:56 AM                        Check the input with an ohmmeter and if the level is a problem, I'd use a small preamp. I agree about the grounding issue. You might have to fiddle with it.  |  IP: Logged Brad Allen Jedi Master Film Handler Posts: 688 From: Evansville, IN, USA Registered: May 2000 posted 01-11-2004 12:50 PM                     Would anyone be so kind as to explain further about what "grounding Issue's" I may encounter? Also, please explain further on the "in phase issue". Thanks for the help!  |  IP: Logged Gordon McLeod Film God Posts: 9532 From: Toronto Ontario Canada Registered: Jun 99 posted 01-11-2004 01:51 PM                     The outputs of the reverse scan reader are balanced in that the -and th + are neither tied to ground Most Mono systems were an unbalanced input so the - side is tied to ground This can cause a lot of hum and noise when the reverse scan is connected as such You may want to get a pair of high quality matching transformers  |  IP: Logged Frank Angel Film God Posts: 5305 From: Brooklyn NY USA Registered: Dec 1999 posted 01-11-2004 03:29 PM                        Underline "high quality." I tried to use a Inovonics 4trk preamp unit designed for RTR tape transports to Simplex penthouses. Needless to say, what should have worked in theory (the numbers were correct) sounded like:bs:. There is a wide range of transformer quality out there; buyer beware.  |  IP: Logged Gordon McLeod Film God Posts: 9532 From: Toronto Ontario Canada Registered: Jun 99 posted 01-11-2004 03:38 PM                     One of the problems you would have encountered with that inovonics is the response curve of it as it would have probably been based on the NAB characterisitics not the CCIR or the SMPTE curve also the head impedance would have been an issue as that unit would have been designed for a high impedance head and the film heads for Commag prints are extrememly low impedance If memory serves they typically are designed to reflect into a 30 ohm load  |  IP: Logged Brad Allen Jedi Master Film Handler Posts: 688 From: Evansville, IN, USA Registered: May 2000 posted 01-12-2004 10:47 AM                     Ok, this is beginning to sound like something I shouldn't even attempt. Thanks all for outlining the pitfalls.  |  IP: Logged Gordon McLeod Film God Posts: 9532 From: Toronto Ontario Canada Registered: Jun 99 posted 01-12-2004 10:37 PM                     There are many transformers out there a 600:600 ohm one is all you need and the bandwidth of a kono system is so restricted it doesn't have to be the best one either Mouser has them for telephone coupling (hell they are the one s used on most music distribution amps)  |  IP: Logged

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