Looking to do some wave shaping, need to smooth 2 octave down

[Earthscum]

I'm looking for something that will round off the corners. I was thinking of an integrator, but bass is good while highs suffer badly when it's mixed with the other octave and fundamental squares.

I've been kind of checking out schems, but most seem quite elaborate, and seem designed to work with the rest of the circuit.

So, the setup is 576k (because I had em close by... down to 330k works in this circuit before it starts feeding back and affecting the primary input) to a 500kpot to ground, and 576k mixing resistors going directly to the base of a MPF102 (10k S to Gnd buffer).

I'm only looking to round off the corners, which isn't too hard in theory, but the scope shows what is going on in reality, slope as the cap charges, but then a sharp drop and soft landing to ground, then a sharp jump up... close, but no cookie. Integrator works, but high notes suffer in the mix.

Secondly, a triangle (or sawtooth, or adjust between the two). This seems to suffer the same issue as above... highs get lost against mixing with a square.

Semiconductors are only 2 BJT's, 1 SCR, 1 JFET, and 1 CD4013. This is why I'm bugging about this... I want to keep it as simple as possible. I'm really eyeballing a CD4049, or discretes, but want to avoid op amps if possible, although I was also considering TL0xx's as well because of the JFet inputs.

Also, anyone have tips on keeping switching sound from the 4013 out of the system? I tried tank caps, small caps, resistances, a bunch of stuff, and no go. Is this something that might be a typical type of breadboard issue? I can turn down all the pots and still get a high pitched switching noise. It barely shows up on a scope, and are like transient spikes. This just something to expect and just get filtered at the end (say 20kHz 12db LP)?

Thanks all! If needed, I may be able to toss together a schem, but it's pretty much just a typical CMOS octaver driven directly by a Scrynth circuit.

[merlinb]

I'm looking for something that will round off the corners.

Sharp corners always indicate the presence of higher frequencies, so the only way to get rid of them is to dump treble (or use clever phase shifting, like an all pass filter, but either way you still lose the highs). Usual approach is to use 2nd, 3rd or even 4th order filtering. The aim is to keep the frequency response as flat as possible right up to the cutoff frequency, so you retain as much of the audio as you can, before dumping everything higher up. You could perhaps do it with a couple of CMOS inverters, cascaded, each arranged as a multiple-feedback (MFB) second order low pass filter.

[liquids]

I don't really follow your post too well....

But you mentioned sawtooth...and if you have a real sawtooth, sawtooth-->triangle isn't hard, and triangle-->sine isn't hard.  That can be done without and low pass filtering.  If for some reason you want to add it interstage to get the dullest, purest sound, it's certainly possible...

A square wave can be 'stepped' into a sawtooth with a bit of CMOS work...and then proceed

[liquids]

Also, if you want a smooth 2 octave down, and you have a sawtooth that is NOT two octaves down....you can mix square wave octaves (down) to the proper degree with the sawtooth...and yield a 2 octave down sawtooth...helps to have an o-scope to see when you're there....or you can slave over the math and LTspice and the schematic for the 'little brother' and or the 'picsynth' and many other circuits that utilize it...

And again...from there....see my first post....easy to yield a true sine....surf all the synth forums....thomas henry's stuff is easy to find...etc