ideas around CMOS 4069 inverters

[dschwartz]

Hi guys, i´ve been playing around with some ideas of circuits based on 4069 inverters. please let me know your thoughts about these:

- 4069 power amp... i´ve seen that putting inverters in parallel you improve the current capability..Datasheet say that power dissipation of the chip is 700mW, not bad, maybe putting 6 inverters in parallel will make a nice class A amplifier..even better, 2 chips in AB configuration can maybe make a nice 1Watt or more amp..am i crazy? ..i´m thinking on breadboarding something like this, but some initial advice from the experts would be nice.

- 4069 cabinet sim. you can make 2 pole filters from each inverters easily. I designed (not tested) a nice 3-inverter cabsim. as soon as i get a definitive circuit of this i´ll be posting it.

- 4069 dual tremolo: 2 inverters can make a nice square wave oscilator, we could use 4 as 2 independent oscilators and make funny tremolo waves with a LDR driving the gain of other inverter. anyone had tried this?..

- 4069 wah: hmmm..Tim Escobedo already did that...
- 4069 octave up: should be easy to do..with 3 inverters..
- 4069 octave down: using them as flip flops?

well..i just wanted to share my thoughts..i´m bored at wok right now....

[earthtonesaudio]

You can do almost anything with them, with varying levels of success. 

[dschwartz]

i know!..i love these little cheapo chips. you can build a lot of things with them.. PWM´s , VCR´s, amplifiers, oscilators, boosters, fuzzes, flipflops, flashers..the thing i most like is that they auto bias, and need little extra parts.. the bad side is noise (although i have never had a problem with that) and power consumption..well i use wallwarts anyway..

[Meanderthal]

 How bout a CMOS mixer? Could get a lot of active channels from a few chips....

[earthtonesaudio]

Absolutely.  5 inverting buffers, going into 5 volume controls, into one summing mixer.

[Mark Hammer]

Take a look at the input sections of Laney amps.  They use the 4069 a lot.

[dschwartz]

actually, laney SS amps use 4069´s for their high gain channel (e.g. tubefusion 100) distortion. also, on other models, they are used for driving fet switches or relays.

i´m starving for some free time to experiment with them!..
i´ll start with the power amp idea..

[Nasse]

http://www.k-amps.8m.com/PowerAmps/Semicond/FET%20poweramp.htm

[The French connection]

Emma ReezaFRATzitz Overdrive Distortion has an 4069 in i think...
http://www.youtube.com/watch?v=cnmq92jXmp8&feature=quicklist

[dschwartz]

http://www.k-amps.8m.com/PowerAmps/Semicond/FET%20poweramp.htm

interesting.. it uses the inverters as drivers..
i dont understand why he used 3 inverters in a row instead of just 1...

[earthtonesaudio]

Three (or any odd multiple) inverters in the place of one, when used with negative feedback, increases the open-loop gain and results in more accurate closed-loop gains, i.e. better linearity.  Basically the same as if you used a "buffered" 4049 or 4069.

You might want to double check the power figures if you try to make a power amp from inverters.  I think the quotes in most datasheets refer to using them as switches, and not in their linear region.  I would expect the quiescent power consumption would make the amp much less efficient and you'd never get near 700mW audio power output.  However, if you're using them as switching output drivers in a class-D type setup that's a different story. 

[dschwartz]

someone made a class d 4049 amplifier, but i have never seen any info on this...i´ll google it..