Duo-Vibe: a prototype --- DEMO ADDED

[culturejam]

I worked up this circuit as a possible commercial product. Still not sure what the fate of it will be, but at least I got this one cool pedal out of it, if nothing else. I'll post the schematic eventually.

Started working on the design back in February but just now got around to testing the proto boards. Everything works as is and it is dead quiet (no ticking whatsoever).

The downside is that the physical layout of the hardware was pretty bad on my part. So I had to manually wire some stuff that should have been board mounted. And of course, one of the pots was wired backward.  :lol: I do that every damn time.  

I've already revamped the layout to  make it a lot smaller, fix the layout issues, and I ditched one of the pots in favor of a switch (it makes a lot more sense that way).

Okay, so it's a two-stage vibe-phaser thing using LDRs as the variable resistance element. You may recall that I've played around with this general concept quite a bit. So far, this one is my favorite, as it hits the perfect mix between complexity and functionality.

There is a phase mode and a vibe mode. The phase mode sound like the vibe mode with with no pitch shift at all (just filter-like oscillations) and a bit sharper vowel sound. It actually sounds good both slow and fast. Backing off the depth a bit smooths out the triangle LFO into more like a sine wave, which helps on slow speeds.  The pot I ditched in the new design is a wave shape control, but you can really only hear the differences at the extremes. Slow square wave sounds weird, but it sounds great at higher speeds (and passable if the depth is backed off at slow speeds). It doesn't do sea-sick pitch bends, but you can definitely hear it in the vibe mode.

I'll get a demo clip posted in the next couple days. Finish is alcohol inks sealed up with Mod Podge, which also adds a nice texture.

DEMO ADDED:
[soundcloud]https://soundcloud.com/effdub/duovibe-demo[/soundcloud]
It's a little quiet, so you may want to turn up your speakers a bit. Goofed up on the recording level setting.

[gingataff]

Sounds like a cool pedal.
And that finish is gorgeous

[das234]

The finish is great.  Curious how you get that marble finish to look like that, and can't wait to hear it.

[spaceboss]

Looks righteous!

Where to you obtain these here 'alcohol inks'? I've been flirting with the idea of incorporating some darker ones with a reverse etch.

Looking forward to hearing it.

[nzCdog]

Looks righteous!

This!^

Looking forward to hearing it.

and this!!^

Gorgeous finishing... bring the demo! 

[mjcyates]

Love the finish. Looks great!

[culturejam]

Where to you obtain these here 'alcohol inks'?

I get mine from Michaels. But they can be had on ebay or other venues. I use a cotton-pad stamper to apply the ink. Other folks like to drip it on or whatever, but I like the pattern of the stamp.

[billstein]

I have got to try alcohol inks. Do you put those on a bare box? How do you prep it?

[ch1naski]

Two things:

1 - Great finish.
2 - Let's hear the damn thing.
3 - I dont need to hear it,  I want a board.

(did i say "two things"?  )

[LaceSensor]

would buy

[midwayfair]

Beautiful.

Is the vibe vs. phaser mode simply removing a stage, or a cap change? I guess I'll have to wait for the schematic.

... Enter it in the contest?

[Scruffie]

Beautiful.

Is the vibe vs. phaser mode simply removing a stage, or a cap change? I guess I'll have to wait for the schematic.

... Enter it in the contest?

Well i'd guess as is standard he's removing the dry signal... with only 2 stages i'm guessing the caps may already be staggered to get a bit more out of the sound in vibe mode, possibly not though.

Unless he's going with the trem definition of vibe and then could be a stage removal.

So... FET buffer input in to 2 x darlington all-pass stages with a tremulust lune LFO with a few of the mods removed on it?

[culturejam]

Is the vibe vs. phaser mode simply removing a stage, or a cap change? I guess I'll have to wait for the schematic.

It's a cap value change. The value has a huge impact on the sound, and I spent a couple  hours just playing around with value to find two that would make the pedal more versatile. But you could just tweak it for one sound and ditch the switch.

... Enter it in the contest?

I thought about it. But I'm not ready to release the schematic just yet, and I wouldn't feel right about entering a "secret" design. I promise I will make it public in the near future, though.

Well i'd guess as is standard he's removing the dry signal...

Here's what's weird...there is always some dry passthrough. If you completely remove dry, the effect is greatly diminished. I have no idea why, but it works that way. It might be because feedback/feedforward seems to work oddly with only two stages. That's actually why I added the output buffer (to keep the feedback output isolated from the effect input and causing impedance issues). So basically the mode switch toggles between two caps (33n and 3n3, as I recall), and that filters the feedback. As I recall (it's been a while), the larger cap is more vibey (pitch bend).

The LFO started as the stock STM oscillator (which is itself a trimmed down Lune LFO). I tweaked it a bit to make it work better with the LED/LDR in the context of something that's not a tremolo.

So yeah, if you look at the Tourbillon schematic, it's like that but with two stages and a different LFO and different feedback setup.

[Scruffie]

Is the vibe vs. phaser mode simply removing a stage, or a cap change? I guess I'll have to wait for the schematic.

It's a cap value change. The value has a huge impact on the sound, and I spent a couple  hours just playing around with value to find two that would make the pedal more versatile. But you could just tweak it for one sound and ditch the switch.

... Enter it in the contest?

I thought about it. But I'm not ready to release the schematic just yet, and I wouldn't feel right about entering a "secret" design. I promise I will make it public in the near future, though.

Well i'd guess as is standard he's removing the dry signal...

Here's what's weird...there is always some dry passthrough. If you completely remove dry, the effect is greatly diminished. I have no idea why, but it works that way. It might be because feedback/feedforward seems to work oddly with only two stages. That's actually why I added the output buffer (to keep the feedback output isolated from the effect input and causing impedance issues). So basically the mode switch toggles between two caps (33n and 3n3, as I recall), and that filters the feedback. As I recall (it's been a while), the larger cap is more vibey (pitch bend).

The LFO started as the stock STM oscillator (which is itself a trimmed down Lune LFO). I tweaked it a bit to make it work better with the LED/LDR in the context of something that's not a tremolo.

So yeah, if you look at the Tourbillon schematic, it's like that but with two stages and a different LFO and different feedback setup.

Ahhh that ol' chestnut, the volume drop can be gotten around but it isn't always necessary to completely remove the dry for something pleasing. Sounds like the cap swap does the job you want anyway.

I just went with Lune LFO as lots of people seem to favour it  yeah that could be a bit hard on off for vibe... can't see the parts you'd have used in the shot but did you go with something sinusoidal?

[culturejam]

Ahhh that ol' chestnut, the volume drop can be gotten around but it isn't always necessary to completely remove the dry for something pleasing. Sounds like the cap swap does the job you want anyway.

It's not just a volume drop. It really sounds like the effect "depth" is gutted if dry is killed completely. I can't explain it, but that's what my ears hear.

I just went with Lune LFO as lots of people seem to favour it  yeah that could be a bit hard on off for vibe... can't see the parts you'd have used in the shot but did you go with something sinusoidal?

It's still somewhat choppy, even when on the "smoothest" setting. It's a bit lopsided, as is usual with LED/LDR. The LDRs just don't turn on/off linearly. But I tweaked the Depth control a bit to help smooth out the wave a little on less deep settings. It's got some trem-like character, for sure.