Updated EL2009 FG output protection circuit:
Itsu
Ok, i completed this 2009 protection circuit for my FG. I added 10uF tantalum caps at the + and - 16V lines to ground. I was able to adjust (when powered off) the input impedance to give almost zero reflection by setting the parallel 100 Ohms pot to 9 Ohm (both sides the same). I think this is kind of low, when powering on, i see many signals appear, which looks like oscillations to me. Does there need to be a physical grounded barrier between the input and output? Anyway, the buffer seems not to work as i do not see any output signal when applying ±16V and a 10Vpp sine/square wave signal. According to the EL2009 data sheet, this should be the correct layout, see picture. Removing the schottky diodes shows some signal, but less then the input, so i wonder of the above mentioned pin layout is the correct one. The EL2009's get fairly warm to the touch after a while. Itsu
« Last Edit: 2016-12-17, 21:18:58 by Itsu »
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