Using 4049's

[ItZaLLgOOd]

I have some 4049UBE's and I want to start working with them but when I look at schematics using them I get a little lost. 

I'm not quite sure as to how to figure the gain and I don't see any "biasing" like on a TL072.  Can you put diodes in the feedback loop and get soft clipping? (Like the CMOS Grace posted earlier)  The Double D has a gain stage before and a buffer after.  Is that the way to go?

Are there some general guidelines to go by or should I just wing it on the breadboard.

[gez]

Can you put diodes in the feedback loop and get soft clipping?

You get soft clipping with CMOS anyway.  Adding diodes will, if anything, make the distortion harsher.

Plenty in the archives to answer your other questions.  Unfortunately I haven't saved the links to the relevant threads, but shouldn't take too long to find...

[Ripthorn]

If you look at a circuit like the Red Llama, you will find no FETs in it, just the 4049, so it depends on what you want.  The Red Llama seems to be more of a fuzz while the Double D is more of an overdrive/distortion.  Are you wanting to make your own design?  Another circuit that uses a 4049 is the ROG Three Legged Dog and that only uses a single FET.  I think that there are more than enough inverters on a 4049 to eliminate the need for an input FET stage, but that doesn't mean it can't help.

[WGTP]

http://www.aronnelson.com/gallery/main.php/v/WGTP/cMOSilator.GIF.html?g2_imageViewsIndex=1

http://www.aronnelson.com/gallery/main.php/v/WGTP/Red+Rooster.GIF.html?g2_imageViewsIndex=1

These should help get you started.  Some people think the 4049 sounds better when driven by a preliminary stage, like the RoG stuff.  Good luck.   

[ItZaLLgOOd]

Thanks for the links.  I think that what i needed to get started.  My idea is to make some sort of Double Muff. Like the Double D but 2 different voiced Big Muffs. 

The CMOS stuff looks to be easier to work with and I was concerned that I was missing something that was way over my head. 

Thanks for the help.

[earthtonesaudio]

DC feedback (like a resistor) from the output to the input of the inverter biases the output to 1/2 the supply voltage, due to symmetry between the N- and P-channel MOSFETs.

With most inverter-based audio circuits, gain = Rfeedback/Rin.

CMOS inverters have high input impedance but also high output impedance, so a buffer on the end helps drive whatever comes after.  But you can get away without one in a lot of cases.  See: Red Llama/Tube Sound Fuzz.

[snap]

or does it bias the INput?

[WGTP]

For a CMOS BMP, search for the Twenty-Two Sevenths.

[earthtonesaudio]

or does it bias the INput?

Oops, yes.  You're right.