Enveloped phaser

[Kipper4]

So I'm looking into enveloping a phaser what should I be looking to envelope?
Speed? Effect intensity?
What?
Also how many stages?
Thanks guys
Rich

[strungout]

Both? Must be able to switch between speed or intensity?

How many stages? More! Ok, maybe 2-4?

This could be fun, but my knowledge is limited. I remember breadboarding an MXR phase 90 once...

[duck_arse]

how about: 4 stages: 2 driven by one lfo, and 2 driven by a swept-rate lfo (up and down, natch) or an eveloped lfo, all mixed at the end?

[Kipper4]

Thanks for that.
I wonder how pigtronix does it?
I looked through the stompbox cookbook and havent found the right articles yet.
I also looked at Nelsons pwm phaser.
@DA i think I have an idea how to do that now, thanks to you.
I'm going with 4 stages rc4558 op amps. (thats whats in the video)
I'm in a pigtronix phase. its a bit like an artists blue phase but with more swirl.
I was gonna call it the dervish but its been taken. So whirly bird it is.
I'll post up a preliminary scheme later.
Bare in mind it's a work in progress so its a Q&D schematic for later cleaning up.

[whoisalhedges]

I'm seeing more and more envelope-controlled modulation effects, and I love it.

I'm still too broke for the Keeley Dynatrem, or the Pigtronix Envelope Phaser, or that crazy Catalinbread trem/fuzz (and I'm still too green to design my own) but I'm licking my lips.

[Kipper4]

Well you could be in luck since I'm a cheap skate. Less parts is the new black.


Q&D demo

[Kipper4]

I tried a 2 stager but it wasn't swirl enough and was getting drowned out with a distortion in tow.
So I swapped to a 4 stage. I even tried a 6 stage but was too cheap to add the extra vactrols and ran into trouble with running 6 stages from 4 vactrols. I shouldn't be surprised.
I'd really like to go with 8 stages but it has to be comfortable in a 1590BB.
So stay posted I could get some mission creep yet.

[strungout]

Sounds good!

And +10 for the Weezer song!

[Mark Hammer]

I added envelope control of the speed to a Phase 90 build, and quite like it.  It was a simple matter of sticking a photocell in parallel with the speed pot and using the a half-wave rectifier (a la Dr. Q) to light up an LED instead of feeding a 1N914.  I imagine it might be a little different with envelope control of another parameter (like depth, mix, or feedback), but the time constants have to be selected very carefully for  the envelope control to correspond to your playing in a musical way.  It can't decay too quickly or else you end up with a jarring transition.  Keep in mind that you can't perceive it as decellerating unless this sweep was a little slower than the last one and a little slower than the one before that, which is going totake a couple seconds to hear.

Envelope controlled mix, on the other hand, could have a near instantaneous attack and decay, because you'd be using it as a switch - pick hard and you hear phasing.

[Kipper4]

Heres the Q&D 1st schematic.

I tried the Univibe cap mods and it sounded muddier to me, maybe thats the univibe mojo.....

Edit; note the phaser/vibe switch
When engaged (phaser mode) it adds the dry signal to the wet (gain of 5).
The gain was a trial and error thing. I tried larger gains but they caused issues.
1min 20 in the demo

[Kipper4]

I added envelope control of the speed to a Phase 90 build, and quite like it.  It was a simple matter of sticking a photocell in parallel with the speed pot and using the a half-wave rectifier (a la Dr. Q) to light up an LED instead of feeding a 1N914.  I imagine it might be a little different with envelope control of another parameter (like depth, mix, or feedback), but the time constants have to be selected very carefully for  the envelope control to correspond to your playing in a musical way.  It can't decay too quickly or else you end up with a jarring transition.  Keep in mind that you can't perceive it as decellerating unless this sweep was a little slower than the last one and a little slower than the one before that, which is going totake a couple seconds to hear.

Envelope controlled mix, on the other hand, could have a near instantaneous attack and decay, because you'd be using it as a switch - pick hard and you hear phasing.

Thanks Mark brilliant

"Envelope controlled mix, on the other hand, could have a near instantaneous attack and decay, because you'd be using it as a switch - pick hard and you hear phasing."

this sounds like an good idea......

The lfo as shown is very flexible speed wise. very slow at slowest and very fast at fastest, not quite ring mod but up there. So it will hopefully have a good deal of playroom with the enveloped speed mod. It depends on the envelope a lot.
cheers

[Kipper4]

Another day on the breadboard.
I'm a little nearer with a speed up and slow down feature.
Despite spending most of the day trying to mod the lfo for larger value, just so my speed pot could be a 500k. ie, somewhere in the parish of the ldr in use int the vactrol hanging off the envelope.
I abandoned that idea since i couldnt make it work.
instead i put the ldr across the positive feedback resistor in the lfo R3 schematic above and put a parallel resistor of a slightly lesser value.
I'll play some more tommorow before work then post a scheme before work.

If anyone has a working schmitt/integrator op amp lfo with a 500k speed pot that works and has a good speed range throw me a link.
i tried the p90 lfo and the bugger beat me to a dribbling mess,

or even suggestions on how to change my current lfo so that it can have a 500k speed pot.
I might just learn something.

Cheers I go dribble.

[Kipper4]

ver 3 schematic.
It's not over until the whirly bird sings......

[Kipper4]

[Fender3D]

Hi Rich,

have a glimpse at TC XII phaser (I posted the schematic on the other site).
It uses 2 comparators instead of dual op-amp.
With its LFO you can control speed, width and waveform with resistor(s) on the program jack

[Kipper4]

Thanks F3D will do.

[Kipper4]

Hi Rich,

have a glimpse at TC XII phaser (I posted the schematic on the other site).
It uses 2 comparators instead of dual op-amp.
With its LFO you can control speed, width and waveform with resistor(s) on the program jack

Brilliant Federico. Guess what I misread. "uses 2 comparators"
looked at the tc, then googled comparator-integrator lfo.
landed here

http://www.moosapotamus.net/files/stompboxology-mo-tremlo.pdf

stole the lfo in fig 3. played on the breadboard with the scope until i got a sine ish wave and a different speed range.
A speed range that suited the project needs more. 'cuase sub sonics aint much cop in a phaser.

Messed with the envelope some more, applied the resultant envelope resistance to the mix control and bam.
Its far from perfect. but im getting results.
I go update the schemo and vid the results
Later guys

[Kipper4]

The 130nf in the lfo was changed from the stompboxology value to make the output more sine ish. It also alters the speed range and voltage output of the lfo IIRC.

The speed pot value was also changed (lucky guess, thank heavens for breadboard 9mm pots)

Initially I changed the depth pot (previous schematics) to a 100k value thanks Stephen.
This is now replaced with the ldr (vact5-B) hooked up to the envelope.
All of which now serves to modulate the effect depth. so pluck that sucker hard you get more phase. Soft and you get less. Taaa Daaah.

At least I think this is what I have on the breadboard. It's been a long sleepless night.

[Kipper4]

Right, yer, eerrmm
I now need to get some stop resistors on the ldr to make it sound good.
Tweek the envelope led driver bias.
Easier said than done

[Kipper4]

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