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Vintage Radio (domestic) Domestic vintage radio (wireless) receivers only. |
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15th Dec 2008, 6:56 pm | #1 |
Retired Dormant Member
Join Date: Apr 2003
Location: Salt Spring Island, BC, Canada
Posts: 368
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3 X EF50 Bedside Radio
I am trying to locate an article on building a bedside radio which I saw in the 1950's, probably in Practical Wireless. The circuit consisted of a untuned RF stage followed by an anode bend detector. The grid circuit of the detector had a potcore coil. The filaments were all in series and there was a capacitor dropper. Does this jog anyones recollection? Thanks.
John. |
16th Dec 2008, 11:12 am | #2 |
Octode
Join Date: Jan 2004
Location: Southport, Merseyside, UK.
Posts: 1,156
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Re: 3 X EF50 Bedside Radio
I've just looked and it's not in any of the 12 issues of Practical Wireless for 1955 or the series August 1954 to July 1955 of Radio Constructor.
John |
2nd Jan 2009, 8:20 pm | #3 |
Octode
Join Date: Oct 2007
Location: Exeter, Devon, UK.
Posts: 1,553
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Re: 3 X EF50 Bedside Radio
Your note triggered one of the few grey cells I have left. I suspect the article you want is from Wireless World in October 1951. I have a reprint of it somewhere. But while I search, I have found the attached update of the original, using B7G valves, from Wireless World, !954.
***** Note: The moderators may want to cut this next bit out, or move it elsewhere. as it is not related to your query, but from other discussions, it may be of interest to someone interested in audio. For at the same time, I also found the original booklets for Mullard 5-10,amplifier, with the more detailed 1957 update which also included a 20W amplifier using EL34, various preamplifiers, and an FM tuner, and GEC 9-12 amplifier, leaflets for the Mullard 3-3 amplifier, and even the booklet for the Wiliamson Amplifier 1955, and the Wireless World Audio Amplifiers booklet of 1955, various designs using PX4, PX25 and KT66, and the P J Baxandall Low Cost High Quality Amplifier booklet of 1958, using EL84. I could scan if there are requests. |
2nd Jan 2009, 8:27 pm | #4 |
Moderator
Join Date: Jun 2003
Location: Oxford, UK
Posts: 27,787
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Re: 3 X EF50 Bedside Radio
These 2 and 3 valve TRF hobbyist designs can be used with a wide range of valves. There were many designs for EF50s in the late 40s / early 50s because these could be bought for literally pennies at the time. Later HF pentodes such as EF80s or EF91s are equally suitable, but these were current valves in the 50s and would have cost a lot more than obsolescent government surplus types.
Paul |