Questions about multiple lm3886 chip amp
Hey everyone I'm currently designing 3 way active speakers compromising of lm3886 power amps and lm358 (or similar) preamps.
Im wondering whether its worth going to the effort of using a separate +/- toroidal with rectifier/regulator and possibly delay circuit or if using zenner diodes and caps off of the +/- 35V is suitable?
Thanks.
Hey everyone I'm currently designing 3 way active speakers compromising of lm3886 power amps and lm358 (or similar) preamps.
Im wondering whether its worth going to the effort of using a separate +/- toroidal with rectifier/regulator and possibly delay circuit or if using zenner diodes and caps off of the +/- 35V is suitable?
Thanks.
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A simple resistor/zener/cap shunt supply off the main rails is ideal for low power opamp circuitry. Why add another transformer when you don't need it.
Just don't use the LM358
Use something like the NE5532 or LM4562 instead. Any delay circuit should really be in the form of a speaker relay to 100% eliminate any switch on/off noises.
Just don't use the LM358
Use something like the NE5532 or LM4562 instead. Any delay circuit should really be in the form of a speaker relay to 100% eliminate any switch on/off noises.
Post #20
http://www.diyaudio.com/forums/analog-line-level/167495-simple-stereo-gain-stage.html#post2199280
Post #37
http://www.diyaudio.com/forums/analog-line-level/167495-simple-stereo-gain-stage.html#post2200615
Any DC servo should be based around a FET input opamp such as the TL071/2
http://www.diyaudio.com/forums/analog-line-level/167495-simple-stereo-gain-stage.html#post2199280
Post #37
http://www.diyaudio.com/forums/analog-line-level/167495-simple-stereo-gain-stage.html#post2200615
Any DC servo should be based around a FET input opamp such as the TL071/2
Maybe it's better to use a dedicated PSU
Yes its based around the LM358 or similar its no simple dc servo though
Maybe I'll share at the end?
It includes balanced input -> line driver receiver -> 50hz notch filter -> 3 way crossover (300hz/3000hz) -> output buffer -> 5 3* lm3886 paralell amps (1 tweeter, 2 mids 2 mid-woofers) each with its own DC servo monitoring the output/backemf made by the speakers to correct it.
If you mean a 35-0-35 toroid then its definitely to much. Look at the data sheet for the LM3886. 84 volts DC as a maximum under signal conditions. That means a 30 volts AC or less transformer and typically a 25 volt would be a more sensible choice.
50,000uF is OK, even for fifteen LM3886's. Good hf decoupling at the chip is just as, if not more important than trying to add more uF's. A 0.1uf film cap and 100uf electro could be more beneficial as long the DC resistance of the rails is generally low from the reservoir caps to the chip. Its all layout dependent stuff though. Fifteen chips means there is going to be considerable wiring of print between everything.
50,000uF is OK, even for fifteen LM3886's. Good hf decoupling at the chip is just as, if not more important than trying to add more uF's. A 0.1uf film cap and 100uf electro could be more beneficial as long the DC resistance of the rails is generally low from the reservoir caps to the chip. Its all layout dependent stuff though. Fifteen chips means there is going to be considerable wiring of print between everything.
Okay great here is the design for the PSU (note I'll change 35V to 25V)
https://imageshack.com/i/pakJ2memp
Here is the crossover design tell me if you see any issues!
http://imageshack.com/a/img903/2629/xq6z2O.png
https://imageshack.com/i/pakJ2memp
Here is the crossover design tell me if you see any issues!
http://imageshack.com/a/img903/2629/xq6z2O.png
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