Quote:
Originally Posted by dieseljeep
The 5Z4 is a real odd-ball tube! The first ones looked like a ballast tube, with a perforated metal housing and two sealed capsules in it. They only made it for a short time, as they were failure prone. The newer 5Z4's were like a metal 6F6. As I stated, the 5Y3 has a 5volt 2amp heater and the same pin-out. The 5U4 has a 3amp heater and too much current for the power transformer.
Regarding the flexible resistor, they all crumbled after so many years. I would use two resistors to equal a value closer to 450-470 ohms.
When DXing with a TRF or a non-AVC superhet, you have to have the volume control set to max, to have the sensitivity to seek out distant stations.
If the radio squeals or motorboats, you might have to use a tube shield on the 6A8GT.
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Well it seems that this radio may not work with an unshielded 6A8 tube in the set as the radio just hums/motorboats really badly when fed a signal from my signal generator or any other kind of signal and unfortunately I don't have any tube shields that are large enough in diameter to fit over an octal tube and short enough to go over a 6A8GT tube so that the gridcap can go over it...
when I have the original 6A8 metal tube in the radio it doesn't do anything (no audio or anything) but then when I turn off the radio I can hear my signal generator coming through loud and clear and undistorted (no hum/motorboating), which tells me that they wired this radio up so that it could only use metal cased tubes I think...
As for the resistors, I already have the 2 270 ohm 2 watt reistors installed in the radio, and I don't really want to have to go back in and remove it and reinstall new ones again as it was a pain in the butt to install them the first time around, is there any sort of problem with having a resistor that's 70 ohms higher than the original? The original resistor as I said previously didn't have any sort of tolerance listing listed for it in the Rider's Service Data which usually means its at least 20% tolerance or more, and 20% of 470 is 94 ohms which means that 540 Ohms is well within the original specs...
