One post, One component - An experiment

[phector2004]

I figured its easier making an oscillator with a bipolar power supply, but not everyone has charge pumps in their stash, and it's only saving about 2 or 3 components needed to run an opamp from 9V to ground.

I guess it's a good candidate for removal, then. The 1N4147 diode was a head-scratcher too... if anything, who not use a 1N4148 

I like the LFOs. Fig 2 looks simple, uses both opamps in the TL072

[CynicalMan]

The diode is reasonable for what Alex wanted to do, and any of the normal silicon diodes would work fine. However, I wanted to open up options for people. So, the LFO could be used as a switch or it could be used to drive the FET for a tremolo. Alternatively, that allows us to use the stage as an SSRP by connecting the 100k pot to ground on one side, power on the other, and with a cap from the gate to the source. We also might be able to switch between the tremolo and SSRP.

[Quackzed]

i like it!

[phector2004]

Here's the latest version

Can't update too much these next few weeks cause I've got a ton of studying with finals.

Cheers,

Phil

[Skrogh]

I'll chime in, this looks interesting!

10k resistor to output of the LFO op-amp.

(Also please keep the inductor there, did a simulation in LTspice, it creates a nice resonant lowpass-filter with a cutoff around some 3kHz if I remember correctly - but only resonant on the negative side.)

I'll be back on the next page 

[phector2004]

Sounds interesting. Any chance you can post a screencap if you get it working?

EDIT: should we just throw in the whole LFO (no. 2) as one "component"
Just this once 

[deadastronaut]

cheat!..

oh go on then...

[earthtonesaudio]

I told my coworker about this and he said there ought to be a Zener diode in there somewhere. 

[phector2004]

Screw studying for today...



I tried and succeeded in adding a zener 

Hope you like it!

[earthtonesaudio]

Somebody ought to add a second 10u cap from pin 5 of the 1044 to GND so we have bipolar power already.
Not me though.  I already used up my turn. 

[phector2004]

Honestly, where does the zener go?

I've never used them before...

The 1044 is in limbo right now... I don't know if it'll be used

[deadastronaut]

can i add an led and 470r from pin 1 of the 072 to ground....it worked on my phase 45 as a rate lfo indicator...

whether it will on this im not sure!..

[phector2004]

Sounds good

Did adding it change anything at all?

[alparent]

OK I would like to make this really interesting by adding a SAD1024.

[Steben]

OMG ...

[slacker]

22n cap in series between the bottom of the 10u cap and ground in the LFO  

[Skrogh]

Did some simulations back at post #68:

This is with a +1/-1V sinus input at 220Hz


This with the 0r set to 100k

[phector2004]

 

Well I'm baffled... Looks cool though, maybe I'll pick up an inductor from the local place when I'm done exams, see what it sounds like with a guitar signal

Thanks!

[Skrogh]

You might want to put in a buffer in front of the circuit, if you are going with the current schem...

Good luck with your exams 

[phector2004]

I'm back!

Forgot to order the less common components needed to build this, but I think I can test it out with similar components

I've got a 12V transformer from a pair of speakers and another unmarked transformer I yanked out of an RF booster, so maybe I can try those out. No idea what the inductance will be, but if they sound any good, I'll try measuring

Any ideas as to which winding makes a more suitable wah inductor? (Or if power transformers will work at all!?!)