Optochopto: A wah based tremolo

[dano12]

This was originally designed as part of my Armageddon Processor monster build. But that will probably take another year to complete

I thought the optochopto part of it was fun enough to put back on the breadboard and document it. Basically, it is a colorsound inductorless wah with the wah pot replaced with a Vactrol driven by a schmitt trigger LFO. I also added switchable resonance capacitors. A fun build!



Also, during breadboarding I thought it would be interesting to remove all the wah/lfo goo and see what it sounds like as a simple booster. The result was very pleasing, a nice single-transistor boost. Give it a try.



More info on the builds here: http://www.beavisaudio.com/Projects/ColorsoundWah/index.htm

Also, the obligatory "on the breadboard shot"

[RickL]

One minor suggestion. sp3t switches are a little hard to find, especially toggles that can be mounted in a simple drilled hole. spdt centre-off switches are easy to find. SW1 could be replaced with an spdt centre-off with only a minor change in sound - the 2n2 is always on, replace the 5n with another 2n2 or a 3n3. The switch gives 2n2, 1.022u and 4n4 (or 5n5).

[andrew_k]

Saw this on your blog, looks cool. Do you have any audio samples?

[Barcode80]

Q&D boost layout:

[Br4d13y]

so, from my perspective of reading (meaning i don't know what half the things are ) is it an envelope tremolo?

[John Lyons]

It's more of a modulated wah from what I can see.
Like a tremolo type chop but with the sound of the wah
being altered by the oscillator instead of the volume of the
signal being varied up and down like the usual tremolo.

I'd also love to hear what this sounds like Dan. Any chance you could whack up a clip?

John

[Nasse]

When I was a kid I did somewhat similar, I just hooked ldr parallel my inductor type wah pot and used a tremolo oscillator to drive a bicycle light bulb to illuminate ldr

[Renegadrian]

Hey someone made a perf? Here is my vero layout...

[arma61]

I'd also love to hear what this sounds like Dan. Any chance you could whack up a clip?

John

+1 pleeeeeeeeease, I don't have a clue how it sounds like, but OPTOCHOPTO must be something worth building it 

Cheers
Armando

[dano12]

If my wife n' kids don't have chores for me tonight, I'll try to get a clip/vid done.

[frequencycentral]

If my wife n' kids don't have chores for me tonight, I'll try to get a clip/vid done.

Just the name 'Optochopto' is awesome, hell it doesn't even have to sound good with a name like that!

It strikes me that the LFO could easily be replaced with an attack/release envelope follower - but what would that be named?

Autoptochopwah? - is that an Amerindian tribe? Or a Chinese dish?

[puretube]

chopping WORM...

[DougH]

If my wife n' kids don't have chores for me tonight, I'll try to get a clip/vid done.

Just the name 'Optochopto' is awesome, hell it doesn't even have to sound good with a name like that!

I agree. He comes up with the best names for his stuff.

[monkeyman]

Do you have a sound clip?

[stringy]

I really want to make this, however I'm quite the noob at doing layouts, so could one of you pros look mine over and see if you think it will work.  I'm sure I didn't represent the switch right, but I think you can get the idea I was trying to show a sp3t.  And the Vactrol, I hope I represented it clearly.  Also, I'm not quite sure about the IC, on his linked page he said he used a quad Schmitt trigger, I searched 40106 on Mouser and came up with a hex Scmitt trigger, but I don't suppose it matters since only one channel is used, right?  Any help would be much appreciated.

[oskar]

1. Sound man...
2. Led1 needs a current limitter. ( Edit: Put it in between R2 and VR2 )
3. Use one or more of the free inverters for... more LFO's. Like the psycho LFO


oskar

[Barcode80]

Just an FYI, i built the boost portion of the circuit (on a new cleaner layout, if there is interest i will post it), and though the tone is nice and does add a certain character, it doesn't offer a lot of gain boost. If I could figure out how to goose it a little for more noticeable boost, it would really be a nice booster. any ideas?

[Entrant_21]

Just an FYI, i built the boost portion of the circuit (on a new cleaner layout, if there is interest i will post it), and though the tone is nice and does add a certain character, it doesn't offer a lot of gain boost. If I could figure out how to goose it a little for more noticeable boost, it would really be a nice booster. any ideas?

Try reducing the 6.2M fb resistor to like 2M or something.. I think that'll work.

[DWBH]

So, are there any sound clips of this one?

[Barcode80]

Just an FYI, i built the boost portion of the circuit (on a new cleaner layout, if there is interest i will post it), and though the tone is nice and does add a certain character, it doesn't offer a lot of gain boost. If I could figure out how to goose it a little for more noticeable boost, it would really be a nice booster. any ideas?

Try reducing the 6.2M fb resistor to like 2M or something.. I think that'll work.

yeah, tried that, no dice. I wonder if just cascading it into a mosfet booster would retain the same tonal characteristics jus twith more volume.