Using hex inverters as op amp

[Greg]

Hi, this is probably an example of "a little knowledge is dangerous".

I was wondering if anyone knew if it's possible to hook up 3 hex
inverters (such as from a 4049) as an op amp? I'm thinking 2 inverters
(for non-inverting input) with the output wired to a single inverter's
(inverting input) output. Does anyone know if this would work? I'm
interested in musical applications. I've built Craig Anderton's
Tube-sound Fuzz using the 4049 and it sounds great, that's why I've
started thinking about this.

Thanks,
Greg

 

[Spehro Pefhany]

On Tue, 22 Feb 2005 05:15:17 +1100, the renowned Greg
<zaraakNO@SPAMmad.scientist.com> wrote:

Hi, this is probably an example of "a little knowledge is dangerous".

I was wondering if anyone knew if it's possible to hook up 3 hex
inverters (such as from a 4049) as an op amp? I'm thinking 2 inverters
(for non-inverting input) with the output wired to a single inverter's
(inverting input) output. Does anyone know if this would work? I'm
interested in musical applications. I've built Craig Anderton's
Tube-sound Fuzz using the 4049 and it sounds great, that's why I've
started thinking about this.

Thanks,
Greg

Not really as a traditional op-amp, but you can use a non-buffered
inverter or gate as an AC-coupled amplifier. A single resistor from
input to output biases it (or makes it oscillate if it's buffered).


Best regards,
Spehro Pefhany
--
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