Hi, in this forum i saw a LFO scheme and i think in build a leslie effect



Mount all in a proto board and add a LED/LDR to the triangle wave out, then one pin of the LDR goes to positive of the guitar jack and the other terminal goes to ground.





This was the effect: can you help me to make this more like a leslie effect?

http://www.youtube.com/watch?v=RGvHfGNT8vg

The video is to boring but it's to sow the effect.

What you have described will give you a nice tremolo--amplitude modulation. To get sounds more like a Leslie, you want to get some phase shift going. It's been done--many times, many ways--but it takes a good many more parts than just one LDR. Other people here will suggest things to try. My first thought is the John Simonton "Twin-T Wah" circuit described in the "Technology of Wah Pedals" at Geofex. Substituting an LDR for the wah pot in that circuit and sweeping it with the LFO would give you something interesting. Also check out the Phozer at Runoffgroove.

Yes, it's a modulated tremolo.
I think ad a phase shift like this



N°1 is like the easy vibe, i like to use the N°2 change the 250k pot for a LDR and add a 250k pot in series whit the 0.01uf as a tone control, what do you think?

and what happen if a use this two phase shift in series?

Quote from: ppaappoo on October 06, 2010, 09:46:00 PM
what happen if a use this two phase shift in series?

Starts looking like an Easyvibe, doesn't it! My guess is that method #2 would also work. The point is that you need multiple stages of phase shift (and so more components) and maybe some regeneration to get the depth that you want.

Quote from: smallbearelec on October 06, 2010, 10:07:06 PM

Quote from: ppaappoo on October 06, 2010, 09:46:00 PM
what happen if a use this two phase shift in series?

Starts looking like an Easyvibe, doesn't it! My guess is that method #2 would also work. The point is that you need multiple stages of phase shift (and so more components) and maybe some regeneration to get the depth that you want.

OK ok

A leslie uses doppler (pitch shift) to achieve its effect ....not phase shift.

By modulating the phase, you're making erhm.... a phaser!

Subject title should be modified to    'easy tremelo - project'     or     'phaser - project'

ok ok, and there is a circuit for this doppler effect? how it's work?

thanks for the observation.

Quote from: ppaappoo on October 07, 2010, 10:00:38 AM
ok ok, and there is a circuit for this doppler effect? how it's work?

thanks for the observation.

Someone please correct me if I'm wrong, but I think you're looking for something like a Dunlop Univibe or a Voodoo Lab Micro Vibe.

A Leslie speaker is a complex beast to model. There are really 3 time dependent components:

1) Frequency Response. Because the two horns are enclosed physically in a box, the frequency response of the system changes as the drivers sweep throughout the enclosure.

2) Amplitude. As the horns throw sound away instead of at you, the amplitude decreases.

3) Pitch. Because the horns are moving with some speed, the pitch of the sound decreases as they move away from you and increases as they move toward you. Complicating this matter is the fact that the top driver has two throw horns facing opposite each other, thus creating a rather complex set of pitch changes.

In all honesty, I can't think of a way of doing realtime pitch bending in the analog domain, so this, to me, is a problem for the digital folks. Or, you could just buy a Boss RT-20 for much less hassle.

-Matt