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Author Topic: Biasing  (Read 239 times)


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« on: August 03, 2017, 01:18:24 PM »

Hello! I've designed this biasing circuit (see picture) and was wondering if i should rather go with lower resistors to keep the current flow maximal or if this had no real impact, this will mainly be used to power up an op-amp in a distortion circuit.



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Re: Biasing
« Reply #1 on: August 06, 2017, 07:10:11 AM »

Your circuit needs filter caps on each node,, but there are better ways. ;)

I'll assume you are trying to drop from a large voltage (of say a power amp circuit) down to a low preamp voltage?
If so then just look at the hundreds of SS Amp circuits and you will see how it's done.
Fender often use a large wattage drop resistor then a Zener diode to regulate the low voltage.

Or you can use a common LM7809 3 terminal regulator to get a stable 9VDC supply. Though you still may need a drop resistor as the LM78xx series can only handle about 35 VDC,, check the data sheets. 8)

BTW, there is no need to run your dirt circuit from 9Volts,, just use 15VDC regulator (LM7815) and be done with it.
There's plenty of pdf's around showing how to use LM79xx regulators,, just google the data sheets.
« Last Edit: August 06, 2017, 07:18:50 AM by phatt »
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