The latest version of the Gyrator series of VLF receivers (first developed in the 1990s) is the Gyrator III, a revision of Arthur Stokes' Gyrator II by Guglielmo Di Filippo (observer A-93).
Circuit diagrams and wiring for the Gyrator III are available here in Microsoft Word and PDF formats: .doc [1], .pdf [2]
Links:
[1] http://www.aavso.org/sites/default/files/solar/GYRATOR-III-DI-G-Di-Filippo.doc
[2] http://www.aavso.org/sites/default/files/solar/GYRATOR-III-DI-G-Di-Filippo.doc.pdf
[3] http://www.aavso.org/category/tags/electronics
[4] http://www.aavso.org/category/tags/gyrator
[5] http://www.aavso.org/category/tags/radio
[6] http://www.aavso.org/category/tags/receiver
[7] http://www.aavso.org/category/tags/sid
[8] http://www.aavso.org/category/tags/sid-program
[9] http://www.aavso.org/category/tags/solar
[10] http://www.aavso.org/category/tags/solar-observing
[11] http://www.aavso.org/category/tags/solar-program
[12] http://www.aavso.org/category/tags/sun
[13] http://www.aavso.org/category/tags/vlf
