samchurchill Posted May 30, 2013 Share Posted May 30, 2013 Hi all, Can anyone confirm whether the voltage (normally 5v for Tally) is provided from the tally connections on the back of a Roland V800HD or Roland/Edirol LVS800, or whether you need to supply the voltage in and it's just passive switching that happens inside the mixer? I know the norm is to have the 5v supplied by the mixer but I'm a little confused by the "Mini D-Sub 15 pin type x 2 * Input (max): 12V, 200 mA Open collector Type" description in the Roland tech specs. Thanks, Sam Link to comment Share on other sites More sharing options...
timd Posted May 30, 2013 Share Posted May 30, 2013 Open Collector. Basically, the output will have two states; low and undefined. You will need externally to pull the signal up to a voltage rail with a fairly high value resistor (sized to avoid exceeding the 200mA limit on the output) to get a defined output for both states. Link to comment Share on other sites More sharing options...
samchurchill Posted May 30, 2013 Author Share Posted May 30, 2013 Thanks very much timd, I think I sort of understand this. Would you, or someone else mind describing or drawing a diagram of how I should drive an LED from this sort of connection? Thanks Link to comment Share on other sites More sharing options...
david.elsbury Posted May 30, 2013 Share Posted May 30, 2013 I had a Google on your behalf, this Maxim application note might be of interest [PDF] David Link to comment Share on other sites More sharing options...
samchurchill Posted May 30, 2013 Author Share Posted May 30, 2013 Thanks, I think I found this which would work too Link to comment Share on other sites More sharing options...
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