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Vintage Radio (domestic) Domestic vintage radio (wireless) receivers only. |
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10th Dec 2018, 1:47 am | #1 |
Dekatron
Join Date: Feb 2007
Location: Leominster, Herefordshire, UK.
Posts: 16,526
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Interesting early French Transistor Radio
The set I described in my RWB post as a "rather sad early French tranny" is actually rather interesting. It's from around 1960 and appears to be a Technifrance TR85 or perhaps TR8-85. It has 8 transistors, separate mixer and oscillator, two IFs, preamp, driver and a p-p pair. It covers 5 bands, LW, MW and 3 SW covering 3-24 MHz. It has patina a bit to excess, but internally apart from a very rusty 6*D battery tray it doesn't look too bad. All the transistors are socketed (which may be a contact cleaning nightmare) and the chassis and tagstrip construction looks very neat and should be reasonably accessible once out of the cabinet.
Helpfully, doctsf has a promising looking circuit for a TR8-84 model together with comments about various versions differing only in their waveband coverage. My set has a helpful table listing various manufacturers' transistor types as suitable but I suspect if any are dead, apart from the front end types (which I reckon my Russian AF124 subs could replace) the usual Mullard OC types would do nicely. Watch this space (don't hold your breath, though ).
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10th Dec 2018, 12:39 pm | #2 |
Heptode
Join Date: Dec 2014
Location: Limerick, Ireland.
Posts: 901
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Re: Interesting early French Transistor Radio
Sounds like a good SW model.
Some much later Sony models used separate LO and Mixer. Better performance at higher frequencies. One also used part of FM IF strip as AM IF, and then another mixer transistor at final FM IF to down-convert to 455KHz. Actually some Schaub battery Valve sets used 6.5MHz FM IF amp and then conversion to regular AM IF frequency. The Vidor AM/FM valve portable has no DK96 AM mixer/osc. The FM Mixer osc is the AM LO and the FM first FM IF is the AM pentode mixer. So entire RF & IF on AM and FM is all DF97 valves. Semiconductor FM detector, DAF96 is AM detector and audio preamp. |