Fun with JFETs and servos
- Thread starter jubal81
- Start date
jubal81
Well-known member
So the order came in and I've done some more experimenting.
1. The TL052 doesn't work in the application at 9V. Damnit
2. You can't use half a dual opamp for a servo and the other for audio. Noise with my opamps on hand
3. J201s I got will not bias correctly with a 5K6 drain resistor. Had to go to 15K. Wampler must've had a really big batch of some specific oddballs for this design.
4. Other JFETs I've got all worked fine, with pretty consistent drain voltages. PSA: Don't forget this is a small sample size.
5. JFET clipping looks the same on the scope across part numbers and sound pretty much the same. I think with some tinkering, you could make this work and sound pretty much the same with a lot of different JFETs.
Long story short, I can get this to work pretty well with good results, but it's not a solution that can completely eliminate having to manually make sure everything is working properly - exactly how Chuck characterized it. (Thanks, bud!)
It's a cool concept and I don't regret working on it, but I think I've taken this as far as I need to right now. The thing is a pretty good OD on the breadboard, but I've got others I'd recommend before I'd recommend this one.
1. The TL052 doesn't work in the application at 9V. Damnit
2. You can't use half a dual opamp for a servo and the other for audio. Noise with my opamps on hand
3. J201s I got will not bias correctly with a 5K6 drain resistor. Had to go to 15K. Wampler must've had a really big batch of some specific oddballs for this design.
4. Other JFETs I've got all worked fine, with pretty consistent drain voltages. PSA: Don't forget this is a small sample size.
5. JFET clipping looks the same on the scope across part numbers and sound pretty much the same. I think with some tinkering, you could make this work and sound pretty much the same with a lot of different JFETs.
Long story short, I can get this to work pretty well with good results, but it's not a solution that can completely eliminate having to manually make sure everything is working properly - exactly how Chuck characterized it. (Thanks, bud!)
It's a cool concept and I don't regret working on it, but I think I've taken this as far as I need to right now. The thing is a pretty good OD on the breadboard, but I've got others I'd recommend before I'd recommend this one.
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