What is the difference between 4, 8, 10, X stage phasers?

I got into an interesting debate with the guy from Toadworks here on this subject, and it both cleared up some things for me, and also made the subject more opaque at the same time.

Each stage is an arbitrary amount of phase adjustment. If you take one specific phaser design, which has a certain amount of phase adjustment "per stage", then it makes sense to say that a two-stage version or setting has less phase adjustment per cycle than a four-stage or eight-stage version/setting of the same circuit. However different circuit designs assign different amounts of phase adjustment per stage- it really is arbitrary. So a "four stage" phaser from one manufacturer may have exactly the same amount of phase adjustment as a "six stage" or "eight stage" from a different manufacturer.

IOW it's helpful when comparing designs that are based on the same original design, like clones/variants/updates of a Phase 90 for example. But it's not helpful when comparing completely unrelated designs.

As far as 10 stage versus 4 stage on your PH-3, I would guess that the greater phase sweep of the 10-stage setting is allowing more points where the low frequencies are not canceling each other out.

 

..with a maximum of 90° per stage - right?

Joe

 

I don't know for sure, but I'm curious why there would be that maximum?

 

each stage is driven by an opamp, most the time. Looking at a schematic of a phase 90, or an oberheim phaser or whathave you, you will see the opamps all in line..each one does a certain amount of phasing. I dont know if each does the same amount and if its just in series to create a more prnounced effect or what yet.

You could check out geofex and the technology of phasers article, it also explains how its related to chorus and flanger pedals too.

 

If all stages are equal shift wise, a 8 stage phasor will have a longer sweep than a 4 stage, thus the effect can be "deeper." Personally, I still like the 4 stage the best.

 

I think it is a max(could be wrong) but generally an inductor, which is what the OP Amp in a Phase 90 is simulating, and Capacitor circuit with no resistance is usually just a 90 degree shift. I wouldn't know how to increase the shift, but, again IME and I could be wrong.

 

To the OP - Thank you for asking this question and for your own observation. I use the "Tremolo Effect" setting from the manual, but bump from 4-stage to 12-stage because of that "better bass response." Outside of the band, I like the 4-stage better, but in the band, the 12-stage makes an enormous different in being heard.

 

The red line and the blue line are the same signal, but they are offset from each other a bit. If they were perfectly in phase, they would overlap 100%, we'd only see one line. The amount they are offset is the amount they are "out of phase". The offset is a function of time, one wave starts slightly after the other one starts. The length of time between starts is the amount of phase.

So call that drawing "one stage". Now move the blue line to the right again, the same distance as the first phase difference- that's now "two stages". Imagine between "perfectly in phase" and "exactly out of phase" (mirror image of the red line) there are divisions. Let's say there are 12 divisions, each spaced the same amount apart. There are your 12 stages.

I'm oversimplifying, as a phaser is not just a copy of the signal delayed a little bit. And I am glossing right over the possible maximum of 90 degrees, for convenience. But perhaps this helps illustrate the concept?

 

I think this is the post Bongo mentioned.

 

Perfectly.

 

The out-of-phase copy does move, it draws nearer and farther from the original signal, greater and lesser amounts of phase, following the LFO (circuit that creates the "cycling" control voltage). So those up-and-down blue and red lines are not the up-and-down cycling swoosh, they are instead the pitch of the note you're playing. The amount of space between them shortens and lengthens repetitively, creating the "swoosh".

 

And that's why Subdecay made a mistake when using purple for the Quasar.

 

Ah, no, that's still not quite it. The number is not "how many delayed signals", it's just how many imaginary divisions there are going from zero to 100% of the phase width. You can't hear the stages per se. Within one specific circuit, 8 stage is twice as much phase width as 4 stage, and 12 stages is about 3 times as much phase width as 4 stage.

Note that the "depth" knob controls the depth of the LFO sweep, not the width (time delay) of the phase.

 

Don't worry Dan, I don't really get it either.

 

It's funny because red and blue make purple.