One thing I will say is that until this is verified I wouldn't recommend it being built by anyone who may not be prepared to do a little tweaking. The effect is slightly different from similar phasers in that it has no resistors between the drain and source of the JFETs and this may be a benefit of the 2N4303 JFETs used in the original. If you substitute these for 2N5952 or similar as mentioned on the layout, then there is a chance that the circuit will need tweaking to get it working as intended. I have left a space to add resistors if necessary just to make this easier to tweak for anyone who would like to give it a go. As usual with these phasers, a matched quad is recommended.
The original BJT transistors were TIS97's which are NPN and around 300 hfe and so I have suggested a 2N3904 or similar as an alternative to those. Maybe a BC547-550 or 2N5088 would get you in the ballpark a bit better than the 2N3904 so I'll leave that selection up to you.
The original also used 6 x 741 single opamps and so to save space I have opted for doubles. I'd make sure you socket these as you may want to audition a few to see which double hits the sweet spot for you.
One obvious mod recommendation is leaving out the Oscillator Amplitude trimmer (top) and adding an external pot to control the depth. If you do want to do that just take the wires for the pot from the holes on the board that the trimmer is connected.
I can't find any info about the original, or any clips, so the first person to build it and post a vid on youtube will have their vid added to the post! :o)
.. and the schematic:
No comments:
Post a Comment