Manual phaser

[DWBH]

To control a phaser with a pot, or expression pedal, one would have to eliminate the LFO out of the circuit, right?
Now, where's the LFO in the circuit?
Is it this:

and


The first one is a Phase45 and the 2nd is the phaser from 4mspedals.

[Franky]

Yes, and if you look for a manual phaser, check out the Phozer from RunOffGroove.. 

[DWBH]

Great, I wasn't aware of that feature in the Phozer design. Thanks!

[earthtonesaudio]

Yes, and if you look for a manual phaser, check out the Phozer from RunOffGroove.. 

+1. 

A true phaser is an allpass, so the sound is most noticeable when the phase is moving.  If you plan on making it manual, it will sound like a regular phaser when you're turning the knob, but when you stop turning it might sound like nothing, or just slightly filtered.  A sweepable notch filter like the Phozer will sound like it's "doing something" even when you aren't adjusting the control.

[DWBH]

The idea behind making it manual is so that you can change the speed on-the-fly, or use different speeds without having to lower yourself, stop the concert and 'here we go again!'. Besides, you can make the phaser more rhythmic, as it isn't regular (as LFOs are).

[earthtonesaudio]

So you want manual control over the LFO speed?  That's much easier.  Just put the speed pot under foot control.  Better yet, since both of those circuits use variable resistors to set the speed, put a LDR in parallel with the speed pot, and use an external foot controller to vary LED brightness.  Then you can set the max. resistance and then lower it with the foot pedal.

[DWBH]

No that's not what I want. Sorry if I didn't make myself clear.
The LFOs do this \/\/\/\/\/\/\/\/\/\/\/\
Up and down oscillations.
I want to do that with a rocker pedal.
Like this http://www.youtube.com/watch?v=7lX_fvJIS5Q at 2:35.

[frequencycentral]

Tel-Ray/Morley used to do a foot controlled phaser, lousy quality schematic though:

http://www.morleypedals.com/downloads2.html

http://www.morleypedals.com/pfapfves.pdf

[Franky]

Any of you ever thought about a seekphase? Sequencial controlled phase shifter, a la Zvex.. Theorically, that shouldn't be this hard to do (with a vactrol feeding the FETs)..

I wonder how it could sound..

[Zben3129]

You are talking about having a "wah pedal" but instead of a wah sound you get phase shift with the rock of the pedal, correct?

Zach

[DWBH]

Yes.

[frequencycentral]

You are talking about having a "wah pedal" but instead of a wah sound you get phase shift with the rock of the pedal, correct?

Zach

Thats what the Morley does.

[DWBH]

The brother of my band's drummer has one.
I'll see if I can check it out.

[DWBH]

Any of you ever thought about a seekphase? Sequencial controlled phase shifter, a la Zvex.. Theorically, that shouldn't be this hard to do (with a vactrol feeding the FETs)..

I wonder how it could sound..

Or a proximity controller controling the phase

[slacker]

If I was going to try this I'd do something similar to the ADA Flanger where the "Manual" and "Range" controls let you select either manual control or LFO control or a mix of the 2.

http://moosapotamus.net/IDEAS/ADAflanger/ADAflangerSCH.gif

[Franky]

Any of you ever thought about a seekphase? Sequencial controlled phase shifter, a la Zvex.. Theorically, that shouldn't be this hard to do (with a vactrol feeding the FETs)..

I wonder how it could sound..

Or a proximity controller controling the phase

I also thought about it.. But I coudn't make the RFG working well.. Anyway that can be a solution if you don't want some mechanical parts in your design.. But be sure you're gonna get a headache with the RF stuff.. Very hard to get it work.

[Zben3129]

http://www.runoffgroove.com/phozer.html


"The next step was to add the manual sweep option, specifically in a rocker pedal. RG Keen had already done the hard work for us in his Single Pot Univibe LFO article. The article describes how to use a pot to vary the brightness of an LED. That pot can then be rotated with a rocker pedal (available at Small Bear Electronics), which allows a manual sweep of the Phozer filters for an effect similar to a wah-wah. While the character differs from that of an inductor-based wah, the dual filters produce a more pronounced effect than other twin-T wahs.

We auditioned three different wah pots to find the best taper for this circuit: the Dunlop Hot Potz II, the Fulltone, and the Bourns Life pot. While all three have nearly the same resistance (which is then reduced by the parallel 10k resistor), the Dunlop and Fulltone have a non-linear taper. Since the pot must be wired in reverse, the taper is reversed as well. This produces an abrupt change in resistance at the midpoint of the pot travel and results in an odd "feel." We recommend the Bourns Life pot for its linear taper, allowing it to be wired in reverse with no ill effects."

[puretube]

To control a phaser with a pot, or expression pedal, one would have to...
Is it this:



The first one is a Phase45

just wire a stereo pot* where the drains and the sources of Q1 & Q2 are connected in that schemo,
and omit R12, 13, 14, 15, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26,
C5, 6, 8, 9, 10
IC2B
and of course Q1, 2...


[edit]: *100k...470k

[Paul Perry (Frostwave)]

If the Phase45 is already built, wouldn't you just have a foot rocker picking off a voltage, and run it to R25 instead of the LFO output?
Then you can still switch back to normal use easily.
I suppose the neat thing would be to have a blend control, so you could go from fully manual (or fully pedular!) to fully LFO.

[Mick Bailey]

The Peavey Heritage VTX has a phaser with a pull switch that sets it to manual. A wide range of tone control effects can be had which 'morph' the amps characteristics. I've got one of these at the moment and it struck me what a usable feature this is.