Original FSB thread and schematic available here.
09/06/17 Layout updated! Schematic and layout have now been corrected. Thanks to Ciaran, Pakrat, Destro and the others on FSB for all their work.
If you've already built the previous layout and want to correct it:
- Remove C2. The remaining 10n cap that connected to it becomes 100n and needs to go to ground instead of V+.
- Change the 120p between the TL074's pins 1 & 2 to 47p.
- Change the 100R resistor to 10R.
- C1 is now 47p.
- The 10n cap next to the trimmer is now 100p.
- The link under the trimmer (from lug 1 to lug 2) needs to be moved up one row (between lug 2 and lug 3). Eliminate the cut under the trimmer by jumping it left to right.