Share:
Notifications
Clear all

Radio All dry Bush Battery Radio Project.

Page 1 / 2
 
Till Eulenspiegel
(@till)
Famed V-Ratter Registered
Posts: 4394

In the Riviera Radio topic I mentioned I must find employment for the 1D8GT diode-triode-output pentode valve.  Here it is, a project to shock the purists. An all-dry battery DAC90 look alike. A modified Bush SUG3 chassis has been chosen for the project. The intention was to use a pair of IF transformers removed from a YA series Ultra TV set. Instead, the remains of a DAC90 chassis was bought so the transformers from that chassis will be fitted. The SUG3 has a three waveband coil pack so the project set will like the BA91 also have long, medium and short wavebands.

Application 1d8gt

 circuit of a receiver which employs the 1D8GT.

Battery Bush Radio

The chassis will receive the IF transformers later today.

Till Eulenspiegel.

ReplyQuote
Topic starter Posted : 12/05/2021 1:28 pm
MurphyV310
(@murphyv310)
Reputable V-Ratter Registered
Posts: 316

Hi.

Well as this radio was made during the time of the Rt Hon Clement Atlee I feel this use of a US capitalist valve rather inappropriate.

Personally I'd be using a valve from Mother Russia.  🙄 😌

The valves from the Sputnik although a little later would make a good choice, Current consumption would be lower and it would be a fun project.

I'm thinking of the 1J24B & 1J29B, the frequency changer would require two Rod pentodes the detector would need to be non thermionic and the output the 1J29B.

Cheers Trevor
Radiomuseum Member. Collection HERE

ReplyQuote
Posted : 12/05/2021 8:03 pm
Till Eulenspiegel
(@till)
Famed V-Ratter Registered
Posts: 4394

Hi Trevor,  perhaps the 1D8GT is a lease-lend valve.  I'm sure my valve has the US services designation VT148.

Till Eulenspiegel.

ReplyQuote
Topic starter Posted : 12/05/2021 8:21 pm
Till Eulenspiegel
(@till)
Famed V-Ratter Registered
Posts: 4394

Correct IF transformers fitted and the wiring of the frequency changer and IF amplifier stages done.
Coming up next, the detector and audio amplifier.
Very simple circuit design, no need component group boards.

Bush BA92 2
Bush BA92 3

 Till Eulenspieigel

ReplyQuote
Topic starter Posted : 14/05/2021 12:55 pm
PYE625 and Nuvistor liked
Bobhowe
(@bobhowe)
Trusted V-Ratter Registered
Posts: 70

Hi David looking good looking forward into seeing it working kind regards Bob

ReplyQuote
Posted : 16/05/2021 7:00 pm
Till Eulenspiegel
(@till)
Famed V-Ratter Registered
Posts: 4394

Hi Bob,  good chance there will be results today.   Just about all the under chassis wiring has been done and  only the value of the output valve grid bias resistor has to be determined. On a 90volt HT the 1D8GT pentode section requires -9volts grid bias.  As the bias resistor is in the HT negative return to the battery the HT supply will be reduced by the voltage drop across the resistor. The output valve has a Pout of 200mW @ Va Vsg 90V. GB -9V.

Bush BA92 4
Bush BA92 5

Till Eulenspiegel.

ReplyQuote
Topic starter Posted : 20/05/2021 12:03 pm
PYE625, Nuvistor and Lloyd liked
Till Eulenspiegel
(@till)
Famed V-Ratter Registered
Posts: 4394

News Flash!  The radio actually works, OK, the sound quality could be better which will most likely be a result of using the DAC90 output transformer and a rather bashed up loudspeaker.  AGC performance is good.  Set works well with ten feet of wire as the aerial.  I'll borrow an output transformer from another battery radio and will report the results.

Till Eulenspiegel.

ReplyQuote
Topic starter Posted : 21/05/2021 3:24 pm
Nuvistor and PYE625 liked
PYE625
(@pye625)
Famed V-Ratter Registered
Posts: 4617

When I glance down the "Recent Vrat Posts" I always tend to read this topic as....

All Day Bush Battery Radio Project

Should go to spec-savers !  🤓

To understand the black art of electronics is to understand witchcraft.
Andrew.

ReplyQuote
Posted : 21/05/2021 5:49 pm
Bobhowe
(@bobhowe)
Trusted V-Ratter Registered
Posts: 70

Hi Till set looking good looking forward to see it finished kind regards Bob

ReplyQuote
Posted : 21/05/2021 8:55 pm
Till Eulenspiegel
(@till)
Famed V-Ratter Registered
Posts: 4394

Connected up a loudspeaker and output transformer from a Pye P131MBQ.  Result, a huge improvement in output power. To filter out any IF signal in the audio amplifier a 100pF capacitor has been connected between anode of the triode section of the 1D8GT and chassis.  This component should have been fitted during assembly.

Till Eulenspiegel.

ReplyQuote
Topic starter Posted : 22/05/2021 12:28 pm
Bobhowe
(@bobhowe)
Trusted V-Ratter Registered
Posts: 70

Hi Till just googled Pye 131MBQ looks a good Quality speaker and decent size output transformer would this work with the DAC 90 DAC90A circuit kind regards Bob

ReplyQuote
Posted : 22/05/2021 1:02 pm
Till Eulenspiegel
(@till)
Famed V-Ratter Registered
Posts: 4394

The truth is the 1D8GT isn't really suitable for a table radio set, it was intended to be used in a midget radio sets. What is needed is an output valve which will deliver more power. In the late forties Philips developed a series of valves for use in battery table radios. The valves were DK40, DAF40, DAF41 and DL41, it's the latter I'm considering for my Bush radio. An audio amplifier valve is needed and the DAF91 can be used to replace the triode section in the 1D8.

Info about the DL41:  DL 41, Tube DL41; Röhre DL 41 ID778, Vacuum Pentode (radiomuseum.org)

Till Eulenspiegel.

ReplyQuote
Topic starter Posted : 23/05/2021 11:31 am
Bobhowe
(@bobhowe)
Trusted V-Ratter Registered
Posts: 70

Hi David thanks for the information about the D series valves will start a new thread on this project soon kind regards Bob

ReplyQuote
Posted : 23/05/2021 1:47 pm
Till Eulenspiegel
(@till)
Famed V-Ratter Registered
Posts: 4394

The D40 series valves are difficult to find in the UK.  Actually seen the valves offered at quite reasonable prices in US and Canadian websites, but the postage is expensive.

ReplyQuote
Topic starter Posted : 23/05/2021 2:08 pm
Cathovisor
(@cathovisor)
Illustrious V-Ratter Registered
Posts: 5458
Posted by: @till

The D40 series valves are difficult to find in the UK.  Actually seen the valves offered at quite reasonable prices in US and Canadian websites, but the postage is expensive.

What's the pricing like from mainland Europe?

ReplyQuote
Posted : 23/05/2021 5:41 pm
Cathovisor
(@cathovisor)
Illustrious V-Ratter Registered
Posts: 5458
Posted by: @till

The truth is the 1D8GT isn't really suitable for a table radio set, it was intended to be used in a midget radio sets. What is needed is an output valve which will deliver more power. In the late forties Philips developed a series of valves for use in battery table radios. The valves were DK40, DAF40, DAF41 and DL41, it's the latter I'm considering for my Bush radio. An audio amplifier valve is needed and the DAF91 can be used to replace the triode section in the 1D8.

Info about the DL41:  DL 41, Tube DL41; Röhre DL 41 ID778, Vacuum Pentode (radiomuseum.org)

Till Eulenspiegel.

What about rebuilding a DAC90A to take those valves, Till? Bit of a flight of fancy I know, but at least you have the right valve holders in the chassis...

ReplyQuote
Posted : 23/05/2021 5:43 pm
Till Eulenspiegel
(@till)
Famed V-Ratter Registered
Posts: 4394

Hi Mike,  in fact Bush didn't employ the DK40 in a table top radio?  I've managed to find a DL41 at a reasonable price and the search is on for a DK40.

Till Eulenspiegel.

ReplyQuote
Topic starter Posted : 23/05/2021 5:54 pm
Till Eulenspiegel
(@till)
Famed V-Ratter Registered
Posts: 4394

Seems to be plenty available from European websites. One eBay seller in France has 9 TFK DK40s for £39.05 plus £15.00 postage.

ReplyQuote
Topic starter Posted : 23/05/2021 6:03 pm
Cathovisor
(@cathovisor)
Illustrious V-Ratter Registered
Posts: 5458
Posted by: @till

Hi Mike,  in fact Bush didn't employ the DK40 in a table top radio?  I've managed to find a DL41 at a reasonable price and the search is on for a DK40.

Till Eulenspiegel.

Yes, at least one of the export sets uses it - the BE15 being one such example and I'm reasonably sure there are others.

https://www.radiomuseum.org/r/bush_be15be_1.html

The fact that BRT went to the trouble of producing a service sheet for it (R51) lends me to think that, like the EBS/EU4, this set found its way onto the UK and Irish markets.

ReplyQuote
Posted : 23/05/2021 6:20 pm
Till Eulenspiegel
(@till)
Famed V-Ratter Registered
Posts: 4394

With an RF stage, the DK40 frequency change I reckon the BE15 was/is a cracking performer.

ReplyQuote
Topic starter Posted : 23/05/2021 6:22 pm
Page 1 / 2