Voight-Kampff Chorus, PT2399 Chorus= Solina Ensemble?

[diablochris6]

I was inspired by the Solina String Ensemble and wanted to try and make a "cheap" version with PT2399s instead of BBDs. I gleaned quite a bit of information about the original from J. Haible's recreation (http://jhaible.com/legacy/triple_chorus/triple_chorus.html), especially the initial filter and the inner workings of the LFO. I roughly based the PT2399 side of things on the EQD Sea Machine (Madbean's Gravity Wave) and added the echo lines to my design.

Essentially, the LFO consists of a slow and fast LFO that interact with each other to make an interesting waveform. With some simple filtering, the phase is shifted 120 degrees, and by summing the 0 and 120 degree signals, a 240 degree signal is created.

Each output goes to its own PT2399 chip. While there are no controls for LFO rate, you can control how much of each LFO influences the chorus sound, creating some interesting fast/slow ratios.

As for the audio path, there is a clean blend, and the wet signal first passes through a second order 12kHz LPF before entering the three parallel PT2399s. Each PT2399 can be individually routed from the output via a simple switching jack. Each PT2399 signal goes to the mixer at 100%; the intensity knobs only affect how much the LFO is modulating the IC. Each PT2399 also has its own echo feedback loop for some really ambient tones.



The final assembly will most likely be a doozy due to the stacked boards and separate board that will put the echo controls on one of the sides of a smaller enclosure. It will be like Jenga and Tetris all at once!

[patrick398]

Sounds very cool, thanks for all the info
Wouldn't mind hearing it without the freeze involved

[bluebunny]

Sounds very cool, thanks for all the info
Wouldn't mind hearing it without the freeze involved

This.  Both.   

[bluebunny]

BTW, will you be offering boards, Chris?  Not that I have an enormous backlog to get through, but one more's not gonna hurt, right?   

[Mark Hammer]

The sound is all in the shag carpeting, baby!

But seriously, neat.
Just curious, given that the Freeze pedal essentially recycles a sample, I'm wondering how much of the perceptible periodicity of the chorus is from the chorus's LFOs, and how much is from the Freeze itself.

[BetterOffShred]

BTW, will you be offering boards, Chris?  Not that I have an enormous backlog to get through, but one more's not gonna hurt, right?   

Interest! 

I would be down for a sandwich board as well.   

[diablochris6]

Just curious, given that the Freeze pedal essentially recycles a sample, I'm wondering how much of the perceptible periodicity of the chorus is from the chorus's LFOs, and how much is from the Freeze itself.

I think the Freeze pedal's pitch warble would be at a much faster rate than the chorus effect due to the extremely short sample that is looped. To satiate the masses though, I played a random guitar/bass loop from my EHX 360 of Rachmaninov's Elegiac Cycle through the chorus so you can hear chords with a wide frequency range and single notes.

I will probably offer some boards for sale when my life gets a little less hectic (newborn in the house!).

[anotherjim]

I like.
See, this is why a little daughter board for a single SMD 2399 + the standard caps and a 90deg pin header to make it like a SIL module would be handy...

Would be interesting to hear it on a string machine. There might be a demo of a sample sound on the Nord website of a string machine with its chorus bypassed. I think the Logan "accordion" is simply that.

[diablochris6]

I like.
See, this is why a little daughter board for a single SMD 2399 + the standard caps and a 90deg pin header to make it like a SIL module would be handy...

Would be interesting to hear it on a string machine. There might be a demo of a sample sound on the Nord website of a string machine with its chorus bypassed. I think the Logan "accordion" is simply that.

Your wish is my command (and I happened to be around my computer at the moment).

[BetterOffShred]

The sound is all in the shag carpeting, baby!

But seriously, neat.
Just curious, given that the Freeze pedal essentially recycles a sample, I'm wondering how much of the perceptible periodicity of the chorus is from the chorus's LFOs, and how much is from the Freeze itself.

I think the tone is in the textbooks

[bluebunny]

Congratulations on the Rachmaninov.  Congratulations on getting this done with a newborn.  (And congratulations on the newborn too!)  Not so sure about the accordion...    

If I get impatient (quite likely!) or bored at work (super likely!!) then I might dream up a Vero layout for this.  Fer fun... 

[Kipper4]

This is great. Thanks Chris.
let us know if you're selling boards, I'm in.
Winter project. It's been a busy summer landscaping the garden.
Hoping to get some build time soon.
Rich

[anotherjim]

Argghhh, no, I didn't mean a real accordion!
Funny though, bear with it and the solo lines were starting to be a bit viola-like.
The chordal outbreaks were starting to sound suspiciously like a theatre organ in an empty dance hall. Should you ever have to, that is a very difficult sound to synthesise.

Anyway, I forgot that the Logan String Melody accordion sound is only available if you download the full sample set to a Nord keyboard and play it there - it ain't in the demos.

To see what I mean, play the accordion demo here. Unfortunately, after a promising start, somebody decided it needed an EDM accompaniment. That's the sound of the string machine without the ensemble chorus.

[duck_arse]

..... were so enticeee-ing .....

I like piano accordian.

diablo, it is the image at this location:

Code Select Expand

https://i.imgur.com/wlz7bqS.png

which kills my page if I start at the top of, or try to scroll up to. when i travel over to imgur, it doesn't load the image, because it reports it as being 10754 x 8924, which is quite large. [resizing the image in the page only re-scales, the huge file still needs to load all those millions of pixels, even if you add "width=1000" or something similar.]

and I would like to cast my gaze upon that which everone else is talking aboot, too.

[diablochris6]

..... were so enticeee-ing .....

I like piano accordian.

diablo, it is the image at this location:

Code Select Expand

https://i.imgur.com/wlz7bqS.png

which kills my page if I start at the top of, or try to scroll up to. when i travel over to imgur, it doesn't load the image, because it reports it as being 10754 x 8924, which is quite large. [resizing the image in the page only re-scales, the huge file still needs to load all those millions of pixels, even if you add "width=1000" or something similar.]

and I would like to cast my gaze upon that which everone else is talking aboot, too.

Does this work for you?

Argghhh, no, I didn't mean a real accordion!
Funny though, bear with it and the solo lines were starting to be a bit viola-like.
The chordal outbreaks were starting to sound suspiciously like a theatre organ in an empty dance hall. Should you ever have to, that is a very difficult sound to synthesise.

Haha, sorry about that. You mean nobody but me wants to hear what it would be like if a roomful of Flaco Jimenezes played in a concert hall? I hope that even with the accordion samples, you get the scope of the pedal.

[duck_arse]

thanks, yes, I see it now. there's a lot of it.

[bluebunny]

there's a lot of it.

I printed it at work.  The printer quite sensibly - and completely automatically - put it on A3 paper.