Would a phaser-based chorus effect be possible

[Timmy73]

Hello everyone. First post!
So I was wondering if it would be possible to create an ensemble or chorus type effect with only phasers. Nearly all classic chorus effects used a bucket-brigade delay line, and most of these chips are becoming unattanium. Anyway, one thing that comes to mind is the Eminint 310U organ. It was basically the worlds first string synthesizer. It had a feature built in called "Orbitone", which was designed to mimic a Leslie-style sound, and looking at the schematics, it used no fewer than 3 synchronized bucket-brigade devices. However, it only really sounds like the sound is running through a phaser:
https://youtu.be/ZhaZUSvzvds?t=269
The String Ensemble feature allowed the string sounds to pass through 3 asynchronous modulated delay lines, to create a very lush swirly sound, but it never sounded particularly flanger-y to me. (If you're wondering, yes, this became the ARP Solina)
So in total, I am wondering if running the audio signal through a few very light phasing channels (in parallel so it's not too intese) and modulate each with a seperate LFO, could I achieve this sort of sound? (Guess it wouldn't hurt to try, I can't find any examples of someone doing this in the past.) If I would, I'd probably base it off the schematic in Everyday Electronics December 1977.
Thank you!

[idy]

The original Univibe has two settings: Chorus (mixing with dry) and Vibrato (wet only.) So yes, *any* phaser already does a *chorus.* Look for those with fewer stages and less regeneration.
Your question about parallel phase stages, I don't think so. Isn't it the 'cumulation of phase shift that creates a time delay?

[Steben]

Beware of words and their meaning.

Modulation effects are mostly "variable delay" based.
Chorus and Flanger are roughly the same with some details, phaser is not.
Chorus/Flanger works with absolute delay time whether it is low or high frequency. Phasing introduces delay based on ... phase (right) ... which is frequency-dependable.
On a univibe, the word "chorus" means "modulated + dry signal", but it is simply a phaser effect, not a chorus.

The distinction between chorus and flanger is usually the amount of delay time. larger delays will give Chorus (with almost audible delay), smaller delays will give Flanger (non audible delay, only swirl effect). If the swing of delay reaches 0 you will get through zero Flanger.

Phasers work in very small freq dependent delay (close to Flanger)
If you shift one phase (180°) on 1kHz you get .... 1ms delay. It will be 10ms on 100hz. Both Flanger working area. You'ld need at least double or triple of that for the higher frequencies to get a bit into chorus. And you'ld need splitting the signal in frequency bands to get them a bit in the same delay. That's why one BBD is logical.

[Mark Hammer]

The perceptual difference between a phaser and a chorus is that a phaser only has a few notches, so it directs your attention to them specifically.  In contrast, a chorus uses a delay range that results in MANY notches; so many that we aren't really paying attention to them but rather pay attention to the stagger in pitch and arrival time.

That doesn't make phaser less musically relevant, but the psychological/perceptual differences are substantial enough that making the one do what the other does, to the listener, is extremely difficult, if not impossible.

[Steben]

The perceptual difference between a phaser and a chorus is that a phaser only has a few notches, so it directs your attention to them specifically.  In contrast, a chorus uses a delay range that results in MANY notches; so many that we aren't really paying attention to them but rather pay attention to the stagger in pitch and arrival time.

That doesn't make phaser less musically relevant, but the psychological/perceptual differences are substantial enough that making the one do what the other does, to the listener, is extremely difficult, if not impossible.

True true. I think mainly making a phaser to sound like a chorus is taking a lot of effort and complexity in order to achieve something that can be done so much more easily with - you know - a chorus circuit.

The things I wonder about are more about whether a Leslie sim could use flanger and phaser effects to get closer.

[Mark Hammer]

The things I wonder about are more about whether a Leslie sim could use flanger and phaser effects to get closer.

John Simonton designed the PAiA Synthespin to do just that, but it used a modulated bandpass filter - a MUCH simplified vision of what you imagine,

https://www.diystompboxes.com/smfforum/index.php?topic=102049.0

[Rob Strand]

True true. I think mainly making a phaser to sound like a chorus is taking a lot of effort and complexity in order to achieve something that can be done so much more easily with - you know - a chorus circuit.

IIRC it takes about 8 to 10 first-order all-pass stages to sound even like a flanger.

[ElectricDruid]

There's another chorus/phaser example, which is the Hammond organ "chorus vibrato" circuit. This uses a delay line based on 25 LC filters, which provides a frequency-dependent delay of a couple of msecs or so (iirc - I'd have to check). A variable delay is achieved by crossfading rapidly from the output of one stage to another. The technology is much closer to a string of allphase stages than a BBD, but the crossfading to get a variable delay is not something that turns up anywhere except for things that are trying to mimic this specific effect, as far as I know.

Details of a "clone" circuit here:

http://jhaible.com/legacy/interpolating_scanner_and_scanv/jh_interpolating_scanner_and_scanvib.html

(This is not a simple thing that's going to fit in your next pedal... )

[PRR]

There's another chorus/phaser example, which is the Hammond organ "chorus vibrato" circuit.

That may be simpler done as a mechanical rotor than as a maze of chips.

https://modularsynthesis.com/modules/DJB-scanner/scanner.htm

[ElectricDruid]

There's another chorus/phaser example, which is the Hammond organ "chorus vibrato" circuit.

That may be simpler done as a mechanical rotor than as a maze of chips.

https://modularsynthesis.com/modules/DJB-scanner/scanner.htm

Nice! Incidentally, they say that the total delay time is only 528uSec, so I stand corrected. I remembered more for some reason.

[John Lyons]

The things I wonder about are more about whether a Leslie sim could use flanger and phaser effects to get closer.

John Simonton designed the PAiA Synthespin to do just that, but it used a modulated bandpass filter - a MUCH simplified vision of what you imagine,

https://www.diystompboxes.com/smfforum/index.php?topic=102049.0

Are there any examples of this to hear on the internet?
I can't find any.

[Mark Hammer]

The things I wonder about are more about whether a Leslie sim could use flanger and phaser effects to get closer.

John Simonton designed the PAiA Synthespin to do just that, but it used a modulated bandpass filter - a MUCH simplified vision of what you imagine,

https://www.diystompboxes.com/smfforum/index.php?topic=102049.0

I can't find any either.  I would imagine that one could get a sense of it from pretty much any modulated bandpass, like the EHX Blurst.  Not likely identical, but close.

Are there any examples of this to hear on the internet?
I can't find any.

[PRR]

...they say that the total delay time is only 528uSec...

Them are good photos but that guy is a hacker, not Hammond. "This delay line is one half from a Hammond H-100 organ." Not sure what that really means.