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DIY Stompboxes => Building your own stompbox => Topic started by: hazefuzz on March 26, 2012, 06:34:38 PM

Title: Univox microfazer
Post by: hazefuzz on March 26, 2012, 06:34:38 PM
Maybe someone could help me with my microfazer, I don't understand very well how they work,

when the effect is engage, the guitar signal is lounder but I don't hear the phase sound, and when the rate know is almost at max, I can hear a bit of ..? not phaser but maybe more like a fast oscilation
[url]
http://analogguru.an.ohost.de/193/schematics/Univox_MicroFazer.gif[/url
I'm pretty sure it's the right schematic,

I checked all OP, and there is voltage one each pins, but I nothing about faser, so if someone could help me
Title: Re: Univox microfazer
Post by: Mark Hammer on March 26, 2012, 07:11:02 PM
There is a 100k trimpot.  You will need to adjust it to set the bias for the FETs.  If it is not set right, you will not hear any phasing.  You should be able to adjust it by ear.
Title: Re: Univox microfazer
Post by: hazefuzz on March 26, 2012, 09:11:49 PM
nice you're wright so I trimed the pot i now it's work, but I don't know if it's perfect, It's maybe normal but it's pretty hard to hear the phase when the rate knob is under 11 o'clock

anyway thanks for your help
Title: Re: Univox microfazer
Post by: Mark Hammer on March 26, 2012, 10:01:38 PM
Following the schematic, note that it has no "depth" control or feedback control.  In such circumstances, the value chosen for a depth preset is meant to be a compromise that will be good for most speeds.  Chances are that it will provide a very weak sounding phase-shift at slowest speeds.  One usually also needs to increase the feedback to be able to hear an obvious sweep at slow speeds, and the Microfazer does not have any feedback at all.

There are some modifications I could recommend, but unless we had a picture of the board or a parts layout, I am guessing it would be hard for you to figure out what to do.