Thank you for the link. Yes, I have some plastic film from Rifa (Kemet) too. I got it 25 years ago but it is thinner. Rifa is located in Gränna about 25 km north of my place but they make electrolytics there. Film capacitors are made eslewhere and the film I got back then came from Finland (Evox partner of Rifa) and I picked it up for free in Gränna. Since then, Evox Rifa is a part of Kemet and some plants have been closed, like the one in Kalmar, where my contact person worked.
Hello,
i'm noob.
Do you use this product as it comes,or do you apply aquadag or an other product on it,please ?
I want to build my own electrostatics headphones.
Regards
Plain Mylar isn't conductive on its own, so it will need a high resistance coating of some kind to carry the bias voltage. If it's too conductive, you will lose constant charge operation. In typical electrostatics, constant charge decreases distortion and arcing problems.
There are many, many posts for coating ideas, but if you want reliable and easy, I'd suggest one of the following three.
For quick tests, graphite rubbed into the surface is easy and cheap. It's hard to control precisely though. For more refined work most people seem to be using ER Audio's coating or spray Licron.
There are many, many posts for coating ideas, but if you want reliable and easy, I'd suggest one of the following three.
For quick tests, graphite rubbed into the surface is easy and cheap. It's hard to control precisely though. For more refined work most people seem to be using ER Audio's coating or spray Licron.
Use care to not leave any fingerprints on the diaphragm material. If necessary; clean off any contamination or fingerprints with an alcohol swab.
AFTER the diaphragm is in-place and tensioned; apply Licron Crystal to ONE SIDE only.
Be very careful to not get any of the Licron on the stator edges, as this could create a conduction path which would drain charge away from the diaphragm. For that reason; it's a good idea to mask the outer 1/8" of the periphery before spraying the Licron.
Apply (1) coat "just wet" and let it dry for eight hours before assembling the panel.
If you apply it on a humid day it will blush and dry cloudy looking, but that won't affect its performance. If applied on a dry day; it will dry almost clear with a slight gray/blue tint, about 2 microns thick.
The electrical lead from the bias supply must contact the coated area of the diaphragm. I recommend using a copper foil tape charge ring on the opposing stator that contacts the periphery of the diaphragm when the panel is assembled.
Fear not-- Licron Crystal works perfectly for many years.
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