Phase 90/45 and phaser/univibe mods

[lerxst88]

http://www.youtube.com/watch?v=EFN7YRTjh1g

the video above shows basically what i want to do. anyone have a schematic of where the switches go and what they control?

thanks!!!!!

chris

[frequencycentral]

This is a Phase 45 with univibe mods and two extra stages:

http://www.diystompboxes.com/smfforum/index.php?topic=76657.0

Though I imagine the youtube you linked to is a Phase 90 with similar mods and the ability to switch out two stages.

Phase 45 univibe mods:

http://www.lynx.bc.ca/~jc/pedalsPhase45.html

Phase 90 with mods:

http://www.geofex.com/FX_images/p180plus.gif

This is probably closer to what you are looking for:

http://www.buildyourownclone.com/phaserinstructions.pdf

There are subtle differences between the 45 and the 90. The 90 is not just a 4 stage 45, the 45 is not just half a 90. The 45 has a JFET gate-drain feedback circuit which cuts the JFET distortion a lot, making it sound much smoother, whereas the arrangement in a 90 is much simpler. The 45 also lacks a feedback/regen/resonance resistor, though if you add more stages to make it more like the 90, you can add a 90 style feedback/regen/resonance resistor too.

[gutsofgold]

just wanted to say thanks for that layout Rick! I made a pcb from the JC Maillet schematic months ago but I sold the pedal and then lost the layout in the great crash of my external harddrive.

here's to hoping I can do perf work like you haha.

[lerxst88]

thanks for all the links!!!

unfortunately i dont think byoc makes that phaser anymore because thats exactly what i wanted!

whats the univibe mod?

[frequencycentral]

'Univibe' mods are basically mods to phaser/vibe designs using a 10:1 cap ratio as in the original Univibe, ie 0.1uF and 0.01uF in the 'Univibed' Phase 45 for example.

More good stuff here:

GEOFEX: http://www.geofex.com/Article_Folders/univibe/uvfrindx.htm

Neovibe: http://www.geofex.com/Article_Folders/univibe/vibeupdate.pdf

[lerxst88]

thanks!!!

[aziltz]

'Univibe' mods are basically mods to phaser/vibe designs using a 10:1 cap ratio as in the original Univibe, ie 0.1uF and 0.01uF in the 'Univibed' Phase 45 for example.

More good stuff here:

GEOFEX: http://www.geofex.com/Article_Folders/univibe/uvfrindx.htm

Neovibe: http://www.geofex.com/Article_Folders/univibe/vibeupdate.pdf

Is there an easy mod (ie value-substitution) to change the Phase 90 LFO to that more like the asymmetrical? Univibe Throb?

[jimmybjj]

I'd like to know what the univibe mods are as well. I bought wamplers book but all of the mods are "replace this resistor" (insert picture here) but doesn't actually give the components designation. I didn't have any luck with google. Thanks for any help.

[aziltz]

The Univibe has a Sine Wave LFO right?  That's what I read in RG's article.

What kind of LFO is in the Phase 90?  Is it Sine or something else, like the ROG Tri-Vibe?

[Mark Hammer]

The "idealness" of the LFO waveform will depend on how wide of a sweep one intendeds on producing, and how fast of a sweep.  Some types of sweeps sound great at slow speeds but not so hot at faster ones, and vice versa.  Some sound better for wide sweeps, but make precious little difference if the intent is simple a little wiggle-n-swirl.

It also depends on the manner in which the control element/network responds.  LDRs have a different response than FETs and OTAs.  And if using LDRs, LEDs respond differently as a source of illumination than incandescent bulbs.  All of that necessitates appropriate characteristics of the LFO waveform.

In all cases, what is critical is the "turnaround": the manner in which the sweep reverses direction.  For quick, wiggly, sweeps of modest width, sinusoidal changes in where the phase-shift maxima are tends to sound best.  Producing that sort of sweep may require something different in the LFO waveform feeding a bulb that illuminates an LDR, than in the LFO waveform feeding an FET that responds immediately.