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Radio All dry Bush Battery Radio Project.

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Cathovisor
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I know I'd love to find an example and yes, I'll bet it was a splendid performer. I have two of the mains version, the EU15.

I have a brochure for something much later - the BE75, which looks like the EBS64. Sadly, that brochure doesn't tell you the valves used.

 
Posted : 23/05/2021 5:27 pm
Till Eulenspiegel
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To improve performance I've decided to use a different set of valves. The frequency changer will be a DK40. The IF amplifier a DF91. The second detector and audio amplifier will be a DAF91. Like the DK40 the output valve will be another special valve developed by Philips for high performance battery radios, the DL41.   

Till Eulenspiegel.            

 
Posted : 24/05/2021 9:24 am
Till Eulenspiegel
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The completed radio chassis. 

115307[1]

 The circuit is a Philips design to exploit the D40 series battery valves. Thanks to the superior performance of the DK40 frequency changer valve reception is excellent on all three wavebands.

Bush BA92 cct

 The objective of this project was to create a dry battery version of the Bush BA91 which can house the batteries inside the cabinet.

Bush BA92 13

Till Eulenspiegel.

 

 
Posted : 11/06/2021 11:21 am
Nuvistor, Alex728, PYE625 and 9 people reacted
Bobhowe
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Hi i went to Davids shop yesterday and results are excellent the radio is performing very good and it is working with out the aerial plugged in kind regards Bob

 
Posted : 12/06/2021 5:31 pm
Bobhowe
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Hi i went to Davids shop yesterday and results are excellent the radio is performing very good and it is working with out the aerial plugged in kind regards Bob

 
Posted : 12/06/2021 7:27 pm
Till Eulenspiegel
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A mains power unit has been made for the battery Bush radio. The Eddystone box is approximately the same size as the Ever-Ready B117 HT battery. An LM317 is used to stabilise the 1.4volt filament supply. The HT voltage is 105volts when the unit is connected to 240volt mains. The DL41 output valve can be used on HT voltages as high as 120V, even higher according to the Philips application notes. Performance of this set is excellent on all three wavebands. On battery operation a good earth connection is required unless a direct aerial connection is made to the frequency changer signal grid. Not a nice practise because it detunes the aerial coils.

Bush Ba1
Bush Ba2
Bush Ba3

 Till Eulenspiegel.

 

 
Posted : 20/02/2023 9:31 pm
Bobhowe
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Hi David you have done a great job on the power supply is the LM317 running cool enough ? as I have a larger TO200 that you are welcome to have kind regards Bob

 
Posted : 20/02/2023 9:51 pm
Till Eulenspiegel
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Hi Bob, the LM317 cooling plate is warm to the touch. The set has been on almost five hours and the filament voltage is dead stable, 1.4volts, the figure recommended for "all-dry" valves.  The regulator module has a multi-turn potentiometer but for extra security it has been wound up to max resistance and a 27ohm resistor connected across it. Also, a reverse connected diode between regulator input and output. 

Till Eulenspiegel.

 
Posted : 20/02/2023 10:14 pm
Bobhowe
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Hi David good modification doing the 27 ohm resistor instead of the multi turn potentiometer better been safe for the filament voltage kind regards Bob 

 
Posted : 20/02/2023 10:55 pm
Till Eulenspiegel
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For operation on batteries a replica Ever-Ready B117 or Vidor L5515 can be made. But what about the low tension battery? Ideally, two parallel D cells or in 1955 the U2 cell would be the best solution. But space is restricted inside the cabinet for the two large cells. Perhaps a single U2 cell can provide the 1.5volts @ 200mA with a reasonable service life? Could be possible to squeeze to C cells (U11) above the tuning capacitor.

Till Eulenspiegel. 

 
Posted : 26/02/2023 1:33 pm
Lloyd
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I run my GEC valve portable from a single D cell, but the radio doesn’t get lots of use, even less now Absolute radio’s gone off air. I built a 6V inverter that was switched on by a reed relay that detects current flow on the LT line, that was powered by a small 6V sealed lead acid battery.

Regards,

Lloyd

 
Posted : 26/02/2023 3:57 pm
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