|R.G.||Re: "GEO" Phase 180 PLus|
"Is it like the DOD Phasor 201? If not, what makes it different?"
I'm not familiar with the DOD 201. If you have the schematic for it, I'd be happy to compare the two for similarities and differences.
"What type of op. amp. are you using? "
Generic. I used TL072's, but other duals in the industry standard 8 pin package will work as well. The original used 741 singles, TL022's, and I beileve 4558's at different times.
"Does the placement of the Phase Intense interchange with the V.P.D. circuit? What are the differences of the two?"
You lost me. Can you expand the question?
"What is the relation with the JFET matching Fixture? Where does it correspond to the circuit?"
It doesn't. You use the JFET matching circuit independently first to pre-select a set of four or eight JFETs that have approximately the same Rds/Vgs characteristics so that all the JFETs will be contributing phase shift at the same time, not just one or two. You'll probably need to buy at least twice as many JFETs as you use to get enough to select a matched set.