http://nas.nijkerk.nl/pub/output.pdf
Above a representation of the output of one channel of a Denon DV-2910 cd/dvd/saccd player just after the last opamp.
I want to replace the dc blocking cap (elco 50v/100uF) with a mcp-type of about 10uF.
I want to connect the cap directly to the cinch connector and bypass all those smd muting transistors.
The datasheet of the preceding opamp (njm2068) states that it is advisable to add a 50-ohms serie resistor at the output to prevent oscilation with a capacitive load. Did Denon forget one?
What is the function of the 30K ohm to ground after the dc blocking cap. Can I do without?
Above a representation of the output of one channel of a Denon DV-2910 cd/dvd/saccd player just after the last opamp.
I want to replace the dc blocking cap (elco 50v/100uF) with a mcp-type of about 10uF.
I want to connect the cap directly to the cinch connector and bypass all those smd muting transistors.
The datasheet of the preceding opamp (njm2068) states that it is advisable to add a 50-ohms serie resistor at the output to prevent oscilation with a capacitive load. Did Denon forget one?
What is the function of the 30K ohm to ground after the dc blocking cap. Can I do without?
Your link doesn't work.
I'm no designer but I guess Denon may have omitted the 50R resistor on purpose knowing that the combination of the DC-blocking cap, 30k resistor and (typical) input impedance of amp connected to it won't lead to oscillations. You will probably change the output impedance of the DVD-player by substituting the blocking cap. Just putting in a different cap of arbitrarily chosen value might therefore not be an improvement.
I'm no designer but I guess Denon may have omitted the 50R resistor on purpose knowing that the combination of the DC-blocking cap, 30k resistor and (typical) input impedance of amp connected to it won't lead to oscillations. You will probably change the output impedance of the DVD-player by substituting the blocking cap. Just putting in a different cap of arbitrarily chosen value might therefore not be an improvement.
Marcelinho said:
try different types of around 4.7 to 10uF. I suggest Auricap or silver in oil.
...and tracks capacitance as well!!!
they did not... it is not crucial to put this series resistor with 2068 OP
loads the OP if nothing is connected to the player... solder 30K resistor at the cinch connector.
Boky
Ok, that makes sense to me. I've done that before with a cd-player.
The 10uF with 30K resistor and the input impedance of the amp must give a low enough -3dB point. Just have to look up the formula's again.
So if i run the opamp in class-a by connecting the output with a 10K resistor to +v or -v (before the cap), does that change my -3dB calculations?
The 10uF with 30K resistor and the input impedance of the amp must give a low enough -3dB point. Just have to look up the formula's again.
So if i run the opamp in class-a by connecting the output with a 10K resistor to +v or -v (before the cap), does that change my -3dB calculations?
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