One of my readers sent me a link to french article published in Audiophile n°4, April 1978 by Jon Hiraga.
Unfortuately I didn't understand french and the article is copied in pictures so translators would not work. But with the pictures and some interpretation I can write something about it.
This tweeter was produced by ONKYO in 1978.
Company Adress:
Real ONKYO, 4-4-16 Ueno-Dori, Nada-Ku, 657 Kobe-City, Japan.
As ONKYO was famos with their wooden sides on their amplifiers the tweeter was also availible with wooden plinth.
Sales Office was SUNSEY ENTERPRISE CO. LTD
by J. HIRAGA
Schematic
Nothing really new, it was more or less a copy of the Ionofane.
A main transformer was used. The feedback for the self oscillating tube was done from the elektrode with a fixed capacitor. A resonant coil (L1) was used and had to be trimmed to resonance with C1/C2. The principle is a mix between the fixed Magnat oscillator and the Ionofane's floating oscillator. The ionic tip was different compared to the Ionofane. In the picture below you can see the two coils.
Plasma cell
That was really spectacular. The flame burns freely behind the horn.
A lot of ozone must have been released and ozone smells very unpleasant, apart from the harmful aspect.
Das war wirklich spektakulär. Die Flamme brennt frei hinter dem Horn.
Da muss eine Menge Ozon freigesetzt worden sein und Ozon riecht sehr unangenehm, abgesehen von den gesundheitsschädlichem Aspekt.
Starting the Flame
The Tweeter must be started from outside.
Therefore there was a pen to tip on the electrode to start the plasma.
You can also use a pencil.
Starten der Flamme
Der Hochtöner muss von außen gestartet werden; Im Lieferumfang ist ein Stift enthalten.Sollte dieser nicht mehr vorhanden sein, können Sie auch einen Bleistift verwenden.
different Hornstyle availible
The tweeters could be ordered with 2 different horns. There was a flat horn and a higher horn. The difference was in the sound pressure and frequency response.The flat horn was rated at 96dB/Wm and a frequency response of 3Khz to 60Khz.The higher horn stated at 102dB/Wm and 3Khz to 30Khz.
verschiedene Horn Ausführungen
Die Hochtöner konnten mit 2 verschiedenen Hörnern bestellt werden. Es gab ein flaches und ein höheres Horn. Der Unterschied lag im Schalldruck und Frequenzgang.
Das flache Horn war mit 96dB/Wm und einem Frequenzgang von 3Khz bis 60 Khz angegeben.
Das höhere Horn mit 102dB/Wm und 3Khz bis 30Khz angegeben.
