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DIY Stompboxes => Building your own stompbox => Topic started by: alextdel on February 19, 2006, 01:55:18 AM

Title: mxr phaser 100 -loud click and oversensitive to heavy picking
Post by: alextdel on February 19, 2006, 01:55:18 AM
Has anyone built the MXR Phaser 100 from the general guitar gadgets site? Are there incorrect components on the GGG project??

I get all the types of effect when strumming very gently. BUT the pedal barks very loudly when used with a medium-hard picked note. BUT only when the switch is in position 2 or 4 which would indicate something related to the R1feedback/ Feed forward path. moving the selection switch into position 2 and 4 results in a very loud click.

The circuit is as shown at http://www.generalguitargadgets.com/diagrams/mxr_p100_sc.gif (http://www.generalguitargadgets.com/diagrams/mxr_p100_sc.gif) with the changed resistors listed below.

With all components as drawn, I could only get a 'little effect' with the switch in pos 1 and 2 and then only when the speed pot R57, was within a 15 -20 degrees of full rotation.
 I have now got effect in all four positions by following a suggestion I found in the archives of changing R42 to 3K9, R43 to 22K, R40 to 47K, R39 to 47K, and R56 to 4K7.

Any suggestions?????
 I have checked for track shorts, incorrect wiring of the switch and incorrect components. The transistors are 2n5088 as suggested on the build list at the above website, the build list quotes 5 transistors,but the schematic shows only 4.

thanks