Hi,
I'm running a noob-project on a breadboard:
I want to create a preamp using the NE5532 opamp.
What I want to get running at first is an adder and a Sallen-Key 2nd Order Highpass.
The HP needs a connection to GND right before the +In of the Opamp.
My problem is the powersupply.
I have this situation:
o 24V
l
l
o 12V
l
l
o 0V
I use an elko-transistor-diode circuit (i don't know its name, but it is the sme like on most china-boards with symmetric power input) to get the virtual GND.
On the same source i run an amplifier connected to 24V and 0V.
Where should i connect the GND of the signal-input and the GND of the opamp-circuit?
I only get a hum with anything i try.
This hum sounds like mass is not connected.
I'm running a noob-project on a breadboard:
I want to create a preamp using the NE5532 opamp.
What I want to get running at first is an adder and a Sallen-Key 2nd Order Highpass.
The HP needs a connection to GND right before the +In of the Opamp.
My problem is the powersupply.
I have this situation:
o 24V
l
l
o 12V
l
l
o 0V
I use an elko-transistor-diode circuit (i don't know its name, but it is the sme like on most china-boards with symmetric power input) to get the virtual GND.
On the same source i run an amplifier connected to 24V and 0V.
Where should i connect the GND of the signal-input and the GND of the opamp-circuit?
I only get a hum with anything i try.
This hum sounds like mass is not connected.
Well, schematics would certainly help. I'm assuming you're talking about PSU's with a series pass transistor with a zener diode as the voltage reference, but no way to be sure. Also, your 'situation' is unclear. Is this AC, DC, a transformer, batteries??
Voltages (and their given values) are always based on a reference. If the 12V in your situation is the common reference, the 0V becomes -12V and 24V becomes +12V, giving a symmetric PSU. Important in any situation is all components within a system use the same common. The amp is not designed to run on a symmetric PSU. If you're connecting the amp between 0 and 24V, or between -12V and +12V as far as the preceding opamp stage is concerned, the amp's input will see +12V based on it's expected reference, the 0V. There's a mismatch of commons and DC on the input.
Voltages (and their given values) are always based on a reference. If the 12V in your situation is the common reference, the 0V becomes -12V and 24V becomes +12V, giving a symmetric PSU. Important in any situation is all components within a system use the same common. The amp is not designed to run on a symmetric PSU. If you're connecting the amp between 0 and 24V, or between -12V and +12V as far as the preceding opamp stage is concerned, the amp's input will see +12V based on it's expected reference, the 0V. There's a mismatch of commons and DC on the input.
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