EDIT 2014-10-20
I added a soundclip. Notes: for this clip I had increased the 15K resistor (to the right of IC4) to 33K to lower the effect depth (I found it too wobbly), and I increased the 33K resistor to 47K to keep unity gain. This is as fast as this phaser goes, so it would probably be a good idea to mod the LFO secion aswell to increase the range. The wave-shape could also be better... but this is how it is without too much changes to the original schematic.
DIY phaser from ETI.
I added a soundclip. Notes: for this clip I had increased the 15K resistor (to the right of IC4) to 33K to lower the effect depth (I found it too wobbly), and I increased the 33K resistor to 47K to keep unity gain. This is as fast as this phaser goes, so it would probably be a good idea to mod the LFO secion aswell to increase the range. The wave-shape could also be better... but this is how it is without too much changes to the original schematic.
DIY phaser from ETI.
When I first built it up it was super noisy, so I modded it to reduce the voltage divider before the first phasing stage and I also reduced the makeup gain of the last transistor. Now it's totally usable, however a drawback of the mod is that there can be some minor distortion if you are using hot humbuckers.
It's important to set the Bias trimmer just right. It has a small area where phasing occurs and it controls the waveshape of the sweep aswell.
There are a couple of other things to notice.
When I drew up the layout I mistook the Bias pot for a Depth pot.. I don't wanna add the trimmer to the board, because it would mean even more cuts, links and possible a larger board (now it fits perfectly in a 1590BB). so, you will have to put the Bias trimmer on a separate small piece of vero.
The last thing is that it needs a 100K resistor from the output to ground, otherwise it will pop when switching to bypass (the original didn't have true bypass). It is easily soldered directly to the 3PDT switch.
It's important to set the Bias trimmer just right. It has a small area where phasing occurs and it controls the waveshape of the sweep aswell.
There are a couple of other things to notice.
When I drew up the layout I mistook the Bias pot for a Depth pot.. I don't wanna add the trimmer to the board, because it would mean even more cuts, links and possible a larger board (now it fits perfectly in a 1590BB). so, you will have to put the Bias trimmer on a separate small piece of vero.
The last thing is that it needs a 100K resistor from the output to ground, otherwise it will pop when switching to bypass (the original didn't have true bypass). It is easily soldered directly to the 3PDT switch.
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