Golborne Vintage Radio

Certainly the 1J42A seems to be a bit variable, not designed for what I was doing. Initially before the disaster this little two valve TRF radio was amazingly good. After I just couldn't replicate how well it worked. Using the 1J18B or the 1J24B was a disappointment, yes loads of volume but not easy to tame in a regenerative TRF. In fact some years ago I found that running the HT on 18V gave the effect of an agc that reduced the feedback when a carrier was tuned in so there was no need for a reaction control.
I've been challenged to make a battery valve minimalist superhet radio and I'm considering using Rod pentode throughout. I did a three valve mains version some years back, it initially was ECH81, EF91, EL95 the EF91 anode bend detector was replaced with an EF184 for much improved performance, there are clips on my YouTube channel. I will look at the feasibility of using the Russian valves in this new project, only the wound components will be an issue to whether I can do this as I'm finding winding coils are getting more difficult due to eyesight and dexterity.

Copy any of the 1950s Vidor, but use 2 x 1j24b as pentode mixer (osc to g2) and separate LO. 2x 1N60 as peak detector. You can try pairs of the resistor style coils as IF tuned with 220pF fixed and 47pF variable. About 560uH to 680uH depending on IF desired. I've not tried that trick for an oscillator. It depends if you want performance or minimalism. Use a tap on the PP3 stack for g2 supplies for IF, Osc and audio preamp. The osc doesn't need to be triodised, though you can try it.
If you have an old set of rectangular Philips valve AM/FM IFTs, they will work. You might need to use the 1j29b to replace a triodised DF97, I forget if the 1j24b works at VHF. Copy the Vidor Vanguard if you want AM/FM. No DK96, on AM it uses the VHF mixer/osc DF97 as the LO for MW & LW and then uses the g2 as the LO injection on a DF97 as the AM mixer (it's the FM 1st IF also). Even if only doing AM, it's a good design to copy. Use a pair of 1N60s as a peak detector and 1j24b preamp instead of a DAF96.

You can also use 2x Transistor IFTs coupled back to back (the base inputs connect via a capacitor), thus the collector load coils, which is the tuned bit really, are the anode load and grid feed. Cheap AM transistor radio kits on ebay. Some have 2 x audio transformers and some not. Obviously the transformers are no use for valves, but the ferrite rod, tuning cap and IFTs can be used. Though you need four IFTs for one IF amp.

Hi.
If you remember we discussed the detector Diode with no DC path.
The attached picture is from a 70s USA electronics magazine. Notice the detector in this has no DC path.

Yes, it's a poor design relying on diode leakage. :D

Hi.
I've started to rebuild the two valve TRF that went all wrong latterly.
The issue was in fact the matrix board I initially used. It must have got conductive with all the changes and other things I was doing. So far I've carefully got the layout right on the RF stage and results look very good indeed with better stability on the reaction. May be a few days till I do the audio output as the B16T will take priority again.