Is there nothing that you guys can't answer? After a while, I'd start to think that yunz (that's pure Pittsburgh-ese) were making this stuff up. But then I get valid links to accurate information on the web. Sheesh...
Craig Sawyers came up with the most thorough reply, complete with link. The speakers pictured look like a later model of the ones I have. Apparently these will require a bias voltage. Once again, thanks to all for your replies and help. 73, Don Merz, N3RHT -----Original Message----- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] Behalf Of Craig Sawyers Sent: Monday, December 01, 2003 3:22 PM To: [EMAIL PROTECTED] Subject: RE: [GreenKeys] What's A "Isophon Lautsprecher"? In the 1950's Isophon produced a very high frequency electrostatic speaker for 7kHz and upwards. This was a single-ended design, which usually produces quite a lot of distortion - but only if the diaphragm excursion is large. By limiting the frequency to the very upper end of the audible range the excursion is kept to a few microns, keeping the distortion low. There is a reference to these on http://www.audiocircuit.com/9041-esl-circuit/Commercial/Isophon-ISO/9041CMISO.htm which also has links to specific designs with pictures. Do these look anything like yours, Don? Craig > -----Original Message----- > From: [EMAIL PROTECTED] > [mailto:[EMAIL PROTECTED] Behalf Of Merz Donald S > Sent: 01 December 2003 19:43 > To: [email protected]; [EMAIL PROTECTED]; > [EMAIL PROTECTED]; 'Glowbugs (E-mail) > Subject: [GreenKeys] What's A "Isophon Lautsprecher"? > > > Hmmm...What I have here is 2 small packages about 3 inches square > and 1 inch deep. The label on each one says "Isophon Lautsprecher > St HB 7 S228". Inside each package is a 1/2 inch thick bakelite > and aluminum assembly with a grille on one side and 2 wires on > the other. The label on the back of each of these is the same as > on the package. Molded into the back of each one is "Made in > Germany". Hmmm...it doesn't say "made in West Germany" and it is > too old to be made in post-USSR-breakup Germany. So I conclude > that these were made in pre-war Nazi Deutschland. > > Anyone? Any Guesses? Any referrals to someone who might know? > These were found in an estate in a paper Cameradio bag on which > was written "electro-static". > > Any that's all the clues I've got to give you. Any help appreciated. > Thanks. > 73, Don Merz, N3RHT > DISCLAIMER: > The information contained in this e-mail may be confidential and > is intended solely for the use of the named addressee. > Access, copying or re-use of the e-mail or any information > contained therein by any other person is not authorized. > If you are not the intended recipient please notify us > immediately by returning the e-mail to the originator.(A) > > _______________________________________________ > GreenKeys mailing list > [EMAIL PROTECTED] > http://mailman.qth.net/mailman/listinfo/greenkeys _______________________________________________ GreenKeys mailing list [EMAIL PROTECTED] http://mailman.qth.net/mailman/listinfo/greenkeys DISCLAIMER: The information contained in this e-mail may be confidential and is intended solely for the use of the named addressee. Access, copying or re-use of the e-mail or any information contained therein by any other person is not authorized. If you are not the intended recipient please notify us immediately by returning the e-mail to the originator.(A)
