Lera Op amp

[Kipper4]

Guys
Has anyone used the Lera with a schmitt/integrator lfo ?

Can I just use an LM358 for the op amp or is the model shown in the schematic important?

I've not yet managed to try it it but am curious.

link
http://www.geofex.com/article_folders/lera/lera.htm

Cheers
Rich

[diffeq]

LM158 is the same as LM358 but different industrial / temp. range spec. Otherwise, absolutely the same. LM2904 is identical to LM358. Quad LM324 internally is also the same.

[Kipper4]

Have you tried the circuit though @diffeq ?

[anotherjim]

It's really just an Attack/Decay envelope generator. The single rail opamp chosen because the input can go all the way to 0v and that model can work with that. The Vactrol LED in the feedback offsets the LED Vf so it obeys control input to 0v.
How well it works in your application depends on how you set the minimum and maximum of the envelope sweep to give the required LDR resistance change.

[Kipper4]

I'll set it up on the breadboard and see what i make of it.
Thanks for the help Jim

[Kipper4]

I can see what you mean in a way Jim perhaps when i get it in a working phaser I can adjust (//R with LDR) for better results meantime I have it one the breadboard and I have it working.
First time I made it work. GO Me 

Remains to be seen if its worth the parts as my project has had, significant mission creep already

[telebiker]

Just curious,

Has anyone tried to control speed of the TAPLFO / STOMPLFO based projects using LERA layout?

[telebiker]

There is a photocell that could probably do this

Light resistance : ~1k Ohm
Dark resistance : ~10k Ohm

https://www.eztronics.nl/webshop2/catalog/index.php?route=product/product&product_id=239

[ElectricDruid]

Just curious,

Has anyone tried to control speed of the TAPLFO / STOMPLFO based projects using LERA layout?

I think the Lera layout is probably overkill for this. Lera is designed for things where you've got a pot as part of the circuit controlling something . The StompLFO and TapLFO use 0-5V control voltages, so life is easier.

I did a quick sim and you can set up two 10K pots between Gnd and 5V, one for the 'Fast' rate and one for the 'Slow' rate, and then switch between them with a SPDT switch. To give a slow rise/fall, you buffer the voltage from the switch with an op-amp follower, then add an RC filter. 100K log pot and a few uF for the cap is about right. The output from the filter goes to the Freq CV on the chip.

The only thing to watch out for is that the op-amp needs to be able to drive its output down to ground, if you've got the op-amp on 0-9V and the LFO chip on 0-5V. If the op-amp clips at the bottom, you'll wonder why the output isn't going as low as you expect. Otherwise it's simple.

[telebiker]

Thanks a lot! Will share results once I have something.