diy IF transformers: first attempt.

[Amie]

Would results more qualitative than quantitative, regards measurements? It should at least show resonance of a tuned circuit pretty near where it should be if capacitive loading could cause a shift.

Hopefully reasonably quantitative. I haven't attempted any sort of calibration check, but will do next day or so. I'd expect it to have a constant attenuation, as a cathode follower, gain input to output will be about 0.95.

What I'm not confident of is, signal handling capability up to more than a few volts, especially at higher frequencies.

I suppose the small signal handling will be OK, but "slew" with large inputs could be limited?

Your oscillator...

Sinewave looks really good and pure Clap

Stabilisation method is novel, and 1% variation over the band, shows it's doing its job well.

What happens if you up the HT and use a higher value load, such that the average anode voltage or the supply current is the same?

  Very pleased with what it does, don't really know about the increased HT, some of the components are voltage limited so would need changing before I tried. Apart from that, the output is controlled by the zener (15volts), the two diodes (1.2volts), the output has to overcome these before there is sufficient to start biasing the valve off. Increased HT and anode load resistance would suggest more gain and therefore an easier time for the valve to create the required output, as it stands, removing feedback completely allows the output to go up to around 30volts....

Surprised at the chokes being wound in random direction, reason being, I'd expect them to be machine wound and all the same. Unless Epcos are running two kinds of machines, which rotate in opposite directions...

Strange but true!

And, those valves which are decorating that birthday card (friend of yours I guess?), the pair of smaller ones look like the 1j24b! Which seems to have become my go-to small-signal battery pentode, sort of thermionic BC107. (And as no valve deserves to be compared with sand, I'm now off to wash out my keyboard!)

Yes very good friend, actually the same person let me have a bag of surplus TO18 transistors a while back, I like valves more but if there's no easier way I will use soot or sand. The late fifties valve/transistor hybrid portable radios must make you cringe 

Actually, I'm loth to disassemble the card just yet, but those 1j24b may end up in a superhet front end yet!

I do have a few 1j29b left also that dads friend sent him but they are more suitable for small speaker amplifiers, the Vanguard has one in the output stage in place of the DL96.

Amie