Volksempfänger 301G

[petervk2mlg]

A friend was lucky enough to find a timber Volksempfänger recently. it's a DC mains only model - VE301G.

He is wondering how he could power this given no DC mains any more.

TIA

Peter

[Mitch-W]

Personally, I would use an 1:1 isolation transformer with secondary connected to the bridge rectifier and a 2 or 3 stage PI filter, followed by an adjustable dropping power resistor to dial the voltage to 220V DC.

[petervk2mlg]

Thanks for the suggestion Mitch-W.

P

[Station X]

Following discussion by the moderators political comments have been removed from this thread.

Please stay on topic by only discussing the technical aspects of the set.

[petervk2mlg]

Sadly my friend reports that the REN1821 in the radio has an open circuit filament. It's a very hard valve to find. However, I guess that if he's building a power supply for the set, he can use whatever valves might be available and appropriate.

[Mitch-W]

I repaired quite a few of those RENS and REN valves that initially tested as having O/C heaters by removing the solder in the pins and resoldering them with fresh solder.

Otherwise series string sets are more prone to burning the filaments out in valves, so it might be as well burned out.

[bluepilot]

Originally Posted by petervk2mlg

Sadly my friend reports that the REN1821 in the radio has an open circuit filament. It's a very hard valve to find.

Finding one is quite easy. It's paying for it that's the problem I checked German Ebay for an 1821 or its equivalents and there several on offer, including a couple of NOS. Don't know how much the postage would be.

[petervk2mlg]

Thanks Mitch...good thinking. I'll remind my friend to try that.
Stuart, as you say, the cost is a bit depressing. Postage too is a bit uncertain these days.

[G8UWM-MildMartin]

Have you seen the REN1821-s on the radiomuseum?
https://www.radiomuseum.org/tubes/tube_ren1821-s.html
Translation: Most likely a 12J5 fitted into a european (B5) base.
A 12J5 may be easier to find in Australia. 12.6 V, 150 mA heater instead of 20 V, 180 mA.

[petervk2mlg]

Thanks for that. I'm puzzled however, that a 12J5 could be considered in this case, as you say. - The REN1821 has a 20 volt filament and draws 180 ma. The 12J5 has a 12.6 volt filament and draws 150ma.

[Herald1360]

For operation of a 12J5 heater at 20V 180mA add a 400R (180+200?) 1W resistor across the heater and a 44R (22+22?) 2W resistor in series between the output valve heater and the 12J5 heater.

This could be done inside an adaptor used to convert B5 to IO to mate the 12J5 with an unmodified set.

You could paint the 12J5 gold too

[petervk2mlg]

Thanks to both of you for the suggestion re the 12J5. It looks like a plan.