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Vintage Test Gear and Workshop Equipment For discussions about vintage test gear and workshop equipment such as coil winders. |
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29th Jan 2023, 6:30 pm | #1 |
Diode
Join Date: Jan 2023
Location: Melksham
Posts: 2
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Grayshaw SG50 signal generator
Hello!
I have bought a Grayshaw SG50 signal generator - and there seems to be very little info online! It has 2 tubes in it - a 8D3 6AM6 - (which I found online) and another just marked ā4E4ā (which i can find nothing about..) Iām very new to this - so any help / info on the 4E4 much appreciated. Thank you, Brian |
29th Jan 2023, 7:22 pm | #2 |
Dekatron
Join Date: Apr 2011
Location: Cornwall, UK.
Posts: 13,454
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Re: Grayshaw SG50 signal generator
From an old advert, two Z77's.
Lawrence. Last edited by ms660; 29th Jan 2023 at 7:31 pm. Reason: screenshot |
29th Jan 2023, 7:45 pm | #3 |
Moderator
Join Date: Dec 2010
Location: Exeter, Devon and Poole, Dorset UK.
Posts: 6,865
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Re: Grayshaw SG50 signal generator
The only 4E4 i can find has a CT base.
https://www.radiomuseum.org/tubes/tube_4e4.html It would be an odd choice any chance of aome pictures of the inside of the genny? Cheers Mike T
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Invisible airwaves crackle with life or at least they used to Mike T BVWS member. www.cossor.co.uk |
30th Jan 2023, 6:00 pm | #4 |
Diode
Join Date: Jan 2023
Location: Melksham
Posts: 2
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Re: Grayshaw SG50 signal generator
Thanks ms660, I see the 8D3 6AM6 is the equivalent of a Z77 - the '4E4' is strange one - perhaps its a red herring, and the ID legend is missing somehow? although i assumed it would be etched into the glass..?
Thanks for the info Lawrence! Quite by coincidence, I visited L.F. Hanny's shop in Bath, a few times in the 80's!! Last edited by Station X; 30th Jan 2023 at 10:19 pm. Reason: Linked images converted to thumbnails. |
30th Jan 2023, 10:43 pm | #5 |
Rest in Peace
Join Date: Apr 2008
Location: London, UK.
Posts: 2,508
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Re: Grayshaw SG50 signal generator
That is more like a date / batch code, not a valve type. Its position and appearance are typical of a Brimar date and it decodes as week 4, May 1954 / 64, but would often be followed by a slash and another number that can be decoded to a valve type. But in any case, people can often identify the valve from its internal construction.
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