playing with russian ROD valves.

[BusyBee]

The tinplate I use, I got from an art / craft shop although I would think any reasonable model shop should have some. I have not had any issues with hum in audio but have not tried massive gains. The issue with these valves is that they have little internal screening unlike more usual construction in which the signal grid(s) are naturally shrouded. Actual gain with rod tubes will usually be somewhat lower than with regular (normally higher voltage operation) subminiature valves.

That looks a useful link Nick - thank you x

Tracy

[AdrianPH]

Some time ago I picked up and used some Mil surplus guard receivers from Vulcans, they have 9 wire ended valves in the type 6021 twin triodes and 5840 Pentodes, I think 5 of one and 4 of the other.  They are all fitted with small metal screens and heat-sink clips, mainly I would say for dissipating the heat into the chassis more than anything else.  I made a few milli-watt audio amps from them.  was my introduction into valves again.

Adrian

[ruben]

Hello anybody


It's been a long time since my last post. It really has been a difficult time, with a lot of work and some serious health problems of my parents, which have left me no time for anything. I was finally able to get the FM receiver working with these Russian ROD valves, and I have not been able to update the information in this forum. Here is a video of the radio working, powered by some recycled ni-MH batteries. I have to clean up the schematic. 

[BusyBee]

It doesn't sound like you have had a good time. I hope the health issues with your parents are now resolved. I know from experience that it can get very time consuming with no easy solutions..

Thank you for your update and video. The radio sounds like it is sensitive. I look forward to seeing your schematic.

Tracy

[Murphyv310]

Sorry to hear about your problems, I pray your parents are recovering.
The radio is very interesting, good sensitivity but of course slope detection
What is the HT that you are using and valve line up?

[ruben]

I can't remember exactly, but may be I tried with 60 to 90V (a small chinesse step-up board).  With lower voltage the first valve does not oscillate at FM frecuency (or I was unable to do it). The main interesting think is that I've built a separate quench oscillator with one separate tube, using a small transformer from a ISDN endpoint.
Too I'm using a 22v to 24V as audio output transformer.
Allmost all componets come from scrap.
Total tube count is 4.
I need to reopen the carton case where I put the radio and the pencil schematics after take this video, clean it and put some more info here and there..

[Murphyv310]

Excellent work.
Looking forward to seeing the circuit for this project.

[Kalee20]

Me too!

[AdrianPH]

Me three, I also need to read up on quench oscs and what they are useful for sometime.
Well done for the project, started my own with rod Pentodes, slow progress.

Sorry to hear about your family issues, hope they are resolved in a positive way.

Adrian