I have a few questions to ask:

- I read that the TL072 dual opamp is basically two independant opamps... does that mean they only share the same input/output and nothing else? Could I use two opamps, connect them together for the same/similar results?

- What exatcly is the difference between a "general purpose amplifier", "audio amplifier" and "audio power amplifier" transistor?

Any help appreciated

Ciao.

Quote- I read that the TL072 dual opamp is basically two independant opamps... does that mean they only share the same input/output and nothing else? Could I use two opamps, connect them together for the same/similar results?

:roll: I think dual (and quad) opamps share power supply rails, input and output are normally separate. You can use two single opamps instead of dual, but maybe more space and few more components (like power rail bypassing caps) are needed. And of course ready-designed pcb for duals can not directly used.

Well, mabe there is some info on some manufacturer´s sites, like internal schematics of an opamp. Maybe some components might be shared inside, dunno.

When you pack more than one op-amp on a chip, what they share is power connections, and whatever heat each of them generates.  All input and output connections are entirely independent.  That is why you can always construct a pedal that needs two op-amps out of half a quad or a pair of singles.

The distinction between general purpose, audio amplifier, and power audio amplifier has a bit to do with current handling capability (power amp transistors need to be able handle large amounts of current without overheating to produce more than a watt into an 8-ohm load), bandwidth (audio preamps need to be able to produce reasonable gain at sufficient bandwidth), and noise.  Obviously, you don't care how much hiss is generated by a transistor if you are using it to switch a relay but you DO care if it is amplifying a 10millivolt signal from a voice mic.

Thnx much for the help

Ciao.