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Mystery Resonance Meter - Australian Made - Professional by no Manufacturer
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Return to top of page · Post #: 1 · Written at 10:22:59 AM on 14 July 2026.
	IanRowlands Location: Wahroonga, NSW Member since 14 July 2026 Member #: 2789 Postcount: 3
Hi, New here and hoping I am posting in the right forum: I have a Professionally constructed Australian Resonance Meter. No maker's plate, No serial number. Uses a University Graham W2 200 µA meter, EF91 & 6C4, 6X4 valves, Ducon/Dubilier components, probably Ferguson transformer. The build quality is exceptional and I suspect it was not a commercial instrument, but more likely, university laboratory equipment, trade-school project, CSIRO or government laboratory build and hoping someone out there can recognise this unit and shed some light on it's origins.

Return to top of page · Post #: 2 · Written at 5:18:32 AM on 15 July 2026.
	Brad Administrator Location: Naremburn, NSW Member since 15 November 2005 Member #: 1 Postcount: 7645
Photos uploaded. ‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾ A valve a day keeps the transistor away...

Return to top of page · Post #: 3 · Written at 3:59:22 PM on 15 July 2026.
	GTC Location: Sydney, NSW Member since 28 January 2011 Member #: 823 Postcount: 6970
Clearly a DIY effort, maybe using a design from one of the electronics magazines of the day (RT&H, Practical Wireless, Popular Electronics, etc), or from a text book, or an own design. Q meter circuits are not complicated, so it could well be own-design.

Return to top of page · Post #: 4 · Written at 9:31:40 AM on 16 July 2026.
	IanRowlands Location: Wahroonga, NSW Member since 14 July 2026 Member #: 2789 Postcount: 3
Hi GTC, Yes, that's a possibility - But the build quality is really exceptional, there are perspex rods inside that move a wide brass strip to connect the 2 sides of the tuning cap together. It has been really beautifully machined, way better than a home constructor would do - Ditto for the engraving on the front panel. I think this may have come from a Uni, CSIRO - Someplace with a professional machine shop & proper draftsman... A mystery. A mystery I'm hoping someone will have at least a partial answer to. Whomever made it did a great job - Worth preserving. Cheers, Ian

Return to top of page · Post #: 5 · Written at 9:01:40 PM on 17 July 2026.
	Brad Administrator Location: Naremburn, NSW Member since 15 November 2005 Member #: 1 Postcount: 7645
Photos uploaded to Post 4. ‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾ A valve a day keeps the transistor away...

Return to top of page · Post #: 6 · Written at 8:20:01 PM on 18 July 2026.
	Fred Lever Location: Toongabbie, NSW Member since 19 November 2015 Member #: 1828 Postcount: 1415
Hi Guys, Wow! That's more like a prototype for evaluation. Not a production model. Look at the Perspex and brass work! Definitely a one -off with quality in mind. Apart for the cap hanging off the pot, the rest is ready for life and vibration trials. Not Mil Spec components but very close for a sample. Very interesting. Fred.

Return to top of page · Post #: 7 · Written at 11:12:01 AM on 20 July 2026.
	IanRowlands Location: Wahroonga, NSW Member since 14 July 2026 Member #: 2789 Postcount: 3
Hi Fred, I agree. Hence my reaching out to see if anyone recognises anything about it. The knobs look unique - Hoping someone out there will have some information on it's origins. Cheers, Ian

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