I recently started reading about ESL’s, mostly out of curiosity with no immediate plans to build anything so dangerous as proposed. However, I do have a few 833a triodes and I got to wondering how I might one day use them; SE would be preferable due to limited supply and power demands.
Looking through TubeCad/John Broskie’s blog in posts 179 and 400 a couple of his sketches looked interesting. Also the electrical segmentation principle of the wire stator referred to on Jazzman/Charlie’s blog looks well worth implementing. I’ve downloaded Steve’s excel sheet.
I’ve not yet seen any real life working examples where a single Stator drives two diaphragm’s which leaves me wondering if there is something wrong/flawed with that approach. I would imagine it to be cheaper and quicker to make than two having two stators/one diaphragm. In blog post 400 John say’s “In both examples, the two diaphragms move in phase, which means that effectively we have two single-ended diaphragms working in tandem, so the distortion inherent in single-ended operation cancels as it does in a regular push-pull electrostatic loudspeaker.”
I guess having the Licron Crystal spray on the outer side of the diaphragms might reduce the risk of shorts.
I was also wondering whether a gyrator load on the tube and source follower might work well (better than a choke) in this application driving the capacitive load of an ESL; Mosfets with up to 4.7kV are available.
https://www.tubecad.com/2010/01/blog0179.htm
https://www.tubecad.com/2017/10/blog0400.htm
In the tube circuit shown John has the tube driving the diaphragm, but I was thinking of inverting them, i.e. tube driving segmented stator between diaphragms.
I suppose for safety a coupling cap could be added to block the deadly Tube HT supplementing in a low current dc bias on the stator.
I was unsure whether to put this here or in the Tube/Valve form.
Edit - Stopping the wire stator flexing might be difficult, Perhaps the stator could wound over/either side of a central brace.
Looking through TubeCad/John Broskie’s blog in posts 179 and 400 a couple of his sketches looked interesting. Also the electrical segmentation principle of the wire stator referred to on Jazzman/Charlie’s blog looks well worth implementing. I’ve downloaded Steve’s excel sheet.
I’ve not yet seen any real life working examples where a single Stator drives two diaphragm’s which leaves me wondering if there is something wrong/flawed with that approach. I would imagine it to be cheaper and quicker to make than two having two stators/one diaphragm. In blog post 400 John say’s “In both examples, the two diaphragms move in phase, which means that effectively we have two single-ended diaphragms working in tandem, so the distortion inherent in single-ended operation cancels as it does in a regular push-pull electrostatic loudspeaker.”
I guess having the Licron Crystal spray on the outer side of the diaphragms might reduce the risk of shorts.
I was also wondering whether a gyrator load on the tube and source follower might work well (better than a choke) in this application driving the capacitive load of an ESL; Mosfets with up to 4.7kV are available.
https://www.tubecad.com/2010/01/blog0179.htm
https://www.tubecad.com/2017/10/blog0400.htm
In the tube circuit shown John has the tube driving the diaphragm, but I was thinking of inverting them, i.e. tube driving segmented stator between diaphragms.
I suppose for safety a coupling cap could be added to block the deadly Tube HT supplementing in a low current dc bias on the stator.
I was unsure whether to put this here or in the Tube/Valve form.
Edit - Stopping the wire stator flexing might be difficult, Perhaps the stator could wound over/either side of a central brace.
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Hi,
SE driving requires a constant voltage type transducer ... which means a highly conductive membrane coating ... which means nonlinear drive.
Adding a second membrane on the opposed side of the stator doesn't change the CV nature, but just reduces the distortions from nonlinear drive by partly cancellation due to the mechanical coupling of the membranes via the enclosed air layer.
The classic constant charge transducers allows for highly resisistive membrane coatings and is almost free from distortions.
jauu
Calvin
SE driving requires a constant voltage type transducer ... which means a highly conductive membrane coating ... which means nonlinear drive.
Adding a second membrane on the opposed side of the stator doesn't change the CV nature, but just reduces the distortions from nonlinear drive by partly cancellation due to the mechanical coupling of the membranes via the enclosed air layer.
The classic constant charge transducers allows for highly resisistive membrane coatings and is almost free from distortions.
jauu
Calvin
Well if the stator in the middle is made in a dissipative material with a resistance of >10^6 ohms it will work and has a low distortion.
Membranes could be made from rescue blanket's.
Membranes could be made from rescue blanket's.