SFT II FET operating voltages

[Stymie13]

I'm having a heck of a time getting this one to work properly. Having the same oscillation and inconsistent output issues described by a few others on the main page post. Double checked all component values, tracks, cuts, links, wiring, etc. Tried various combos of J201, 5457s, 5485s with widely varying results. All controls working properly, just really crappy sound and oscillation with some FETs and settings. If someone has a working model and could take the time to post operating voltages, it would be greatly appreciated. Thank you!

[Stymie13]

Still no luck with this build. Double checked each component, tracks and cuts. It was verified but I haven't seen any voltages shared from a working version so thought I would post mine. Any thoughts would be greatly appreciated! FET drain voltages with J201, 5457, 5485, and 4393s were all very close:

Q1 .58-1.08
Q2 9.4
Q3 2.5-3.5
Q4 9.4
Q5 5.16-5.45
Q6 9.4

[Stymie13]

Found an incorrect resistor biasing Q1 and swapped which fixed the major problem. Still had oscillating and found the switch wiring on the current layout on the main page doesn't match the scheme. I changed it and it works fine now.

Q1 4.8
Q2 9.4
Q3 4.1
Q4 9.4
Q5 5.2
Q6 9.4

[Travis]

Actually the way the switch is configured in Alex's layout is correct according to the schematic, but the schematic uses a different numbering for the switch lugs.

The way the switch lugs are numbered in all of the layouts on this site is like this

1 4
2 5
3 6

Follow the same pattern if the switch has more or less poles


Nice work getting your build working!

[Stymie13]

Yeah, I was confused by the way the switch poles were numbered on the FSB scheme. Thanks Travis!