How to wire up a Toshiba TC4007ULP (4007) for distortion?

[Sam]

I salvaged a lot of stuff while cleaning out my garage. I had a couple of shoe boxes full of old, never finished electronic projects I put together sometime during school, a broken distortion pedal (strange Boss-clone called "Session Heavy Metal") and my old DIY analog multi-meter. The interesting bits and pieces were saved before I threw it all away - with the most intriguing being a handfull of Topshiba chips marked TC4007ULP.

I did a search and got the impression these could be used in "4049-type" distortions.

How do I wire it up for basic OD/distortion/fuzz?

From what I gather there are a few stages of Mosfets in there (?).

[niftydog]

it's a 4007 CMOS logic chip, dual complementary pair (of fets) plus inverter.

Look around for articles on biasing COMS chips into their linear region (ie; using CMOS logic chips as audio amplifiers) and try it out!

[gez]

I came up with the Nut Crucher (from Marcos' site) a while ago.  It's a simple circuit built around the 4007.



Could do with a tone stack, perhaps a buffer too, but sounds good as is.

Download the data sheet to get a better picture of how these chips can be wired up as inverters.

[ExpAnonColin]

http://runoffgroove.com/3leggeddog.html

-Colin

[Sam]

Well, thank you! Can't wait to start poking around.

OK, just a newbie-q: Exactly what is an "inverter" and how are they used in distortion circuits?

[gez]

An unbuffered inverter is a p-channel MOSFET stacked on top of a n-channel MOSFET (most data sheets will have a schematic, though the last stage of the nutcruncher - ignoring the bias resistors etc - shows how an inverter is wired), both trannies being matched.  They're used for logic, the output being one of two states - high or low (V+ or ground).  They can be misused to behave as 'linear' (yeah, right!) amplifiers by connecting a resistor from output to gate, this biases the output and inputs to around half the supply voltage and the whole thing works like an inverting amp.

The 4007 allows you to tap into connections that aren't accessible in other chips, allowing even more misuse (see first two stages of above schematic).  Alternatively, you can just wire them up as standard inverters and use them in any circuit that's out there, though they sound slightly harsher to my ears (I kid myself into thinking they have more of a Marshall-like vibe!).

There is more detailed stuff in the archives if you search.  The Art of Electronics has a nice chapter about how they work (one of the few things I did understand in this book when I was new to electronics)

[mojotron]

http://runoffgroove.com/3leggeddog.html

-Colin

The 4007 are not the same as the 4049 - so you would have to convert this design to the 4007 - which I think is totally possible and likely not too tough.

There are 4049 alternatives, I built a 3 legged dog with a 14040UB, and it works, but I think the 4049 is simply a special IC that does have a specific sound. I would say that the 3 legged dog with a 14049 sounds really harsh.. IMO If you are really interested in using digital ICs, it best to go with the exact same parts that others have liked. I am looking for some TI CD4049UBE parts for this build now.

[mojotron]

http://runoffgroove.com/3leggeddog.html

-Colin

The 4007 are not the same as the 4049 - so you would have to convert this design to the 4007 - which I think is totally possible and likely not too tough.

There are 4049 alternatives, I built a 3 legged dog with a 14040UB, and it works, but I think the 4049 is simply a special IC that does have a specific sound. I would say that the 3 legged dog with a 14049 sounds really harsh.. IMO If you are really interested in using digital ICs, it best to go with the exact same parts that others have liked. I am looking for some TI CD4049UBE parts for this build now.

I was wrong on this.. I found a problem with this circuit - actually the 14049UB works exactly the same as the 4049 in this circuit. In fact, the 14049 sounds a little smoother - great sound.

However, does anyone else think the 3 legged dog sounds too thin?