LFOs - How do?

[baremountain]

So I've been tinkering with building and all that good stuff, but my mind keeps coming back to this question about LFOs. Please forgive me and feel free to correct me if I've got a grave misunderstanding here, as I'm totally self-taught, and only know as much as the sum of my disjointed google searches have told me.
My question is mainly about how to make an LFO that's not just a square wave oscillator. I'm aware of the basic square wave LFO stuff from 555s or 40106s and the likes, but I'm curious if there's a way to make a nice non-square wave oscillator using analog equipment. I have read some about filtering the square waves down to triangle or sine, but I know nothing about what that means in practice.
I also discovered a programmable IC where you can upload someone else's script that'll turn it into an LFO with save shape selection, depth, and intensity controls, but I was hoping to get something analog working.
Any advice for this kind of thing? Is it worth going analog or should I get over my technophobia?

Eventually I'd like to get to the point where I can understand creating an offset (I'm assuming you'd just need to send some reference voltage above ground to the gnd pin on your LFO source IC?) & varying parameters like rate, depth, and maybe a shape control (a la the Twin stags/Happiness, which can go from ramp to triangle to saw).

[Dr Satan]

Look at the EA Tremolo for a sine(-ish) wave LFO. The BJT on the right is the LFO. http://www.home-wrecker.com/EAtremolo.png And any dual opamp can net you a square/triangle/sawtooth wave. Google Schmitt Trigger and you should be able to find some useful info. http://electro-music.com/forum/phpbb-fi ... 11_494.jpg You just add diodes on the square for sawtooth. A diode going one way will net a ramp up, while one in the opposite polarity will net a ramp down. Typically you'd put them on the far ends of a trimpot and at 50% you have square and varying degrees of ramped beyond that in either direction. http://www.overclockers.com/forums/atta ... 1271606914

[eatyourguitar]

http://scott.joviansynth.com/fatman/VCO ... ctave.html
this thing in pink using a CD4069

http://www.tradeofic.com/uploadfile/ic- ... 917817.gif
the 555 triangle is 0.5v so needs a lot of gain to do anything useful. you can put the potentiometer in the gain circuit to have one less resistor. it needs to be dc coupled also if you didn't know or you can AC couple through a really big cap.

http://www.electronics-tutorials.ws/osc ... lator.html
the EA trem employs what is called a phase shift oscillator using a single BJT. you can read about it here although they call it a RC oscillator. technically it is an RCRCRC oscillator which also indicates that the name is both erroneous and extraneous.

http://c1.staticflickr.com/3/2930/33984 ... acf6_o.gif
there is also this thing that floats around the internet. for a single 9v supply you only need to connect the opamp like every other 9v guitar pedal ever made. you put two resistors of equal value in a voltage divider from +9v to 0 to make a virtual ground 4.5v its basic basic shit. you don't need to understand how it works. just understand how to power it.

however, it should be noted that in the EA trem and other pedal designs, it is more common to see LFO controlling current. it is also common that the rate of the LFO is current controlled on a pot or trimmer. a voltage controlled LFO will typically have more semiconductors involved. that is why guitar players don't really get the good stuff unless they go deep into the synth place of time waste. filtering your square LFO to a sine is totally doable but only if your LFO rate is not going to change at all. you only need an RC filter (resistor + capacitor) to get a sine from a square. the total energy will be decreased as some of the energy is dumped to ground through the cap to make heat (small amounts, not really hot, this is physics).