zaphod wrote:That article has a pretty good summary of textbook flanger and phaser theory. R.G. Keen writes some great articles. What's interesting is that he seems to be agree with me on some important points.It turns out that the human ear is not too sensitive to phase shifts...The most common commercial phase shifters stop with four stages (such as the MXR Phase 90, Univibe) or six stages (MXR phase 100).So while I might gree that maybe there's some benefit in having some extra fixed phase shift stages, it's really not clear how much of a benfit that really is. Maybe it becomes more useful when feedback is switched on...? Even then, wouldn't it make more sense if different RC values were used in each of the fixed stages to enhance the effect...?...although the effect is noticeable, it's much better if the notches move up and down in frequency.
The most common commercial phase shifters stop with four stages (such as the MXR Phase 90, Univibe) or six stages (MXR phase 100).
R.G. has been known to make mistakes. MXR advertises the Phase 100 as a ten stage phaser and..the schematic verifies this.
If the Phase 100 only incorporated the six swept stages...it would not sound quite the same. The fixed stages reinforce the notches....although the effect is noticeable, it's much better if the notches move up and down in frequency.
Actually...just the opposite. Some companies use 1% resistors or "match" the R/C components in phasers.zaphod wrote:wouldn't it make more sense if different RC values were used in each of the fixed stages to enhance the effect...?
There are reasons why MXR did what they did. The factory documents state that the vactrols are matched. (matching the resistance slope) Vactrols are not inexpensive...you have to "weed" through quite a few to find "matching ones. Vactrols also take up quite a bit of room. Much more than a few caps and resistors.