10-11-2015, 04:44 PM
Been having a few issues with the grid resistors around some of these designs. Fortunately there's a few diagrams of all the various Mixer Frequency Changer circuits, including the Triode Hexode affairs you will find in most home based tube radios. I sort of winded my way back to the grid leak "plate detector" as American designers call it. Any tube that uses a grid as a detector is called "Plate Detector" in old American texts. I do have such a radio that uses grid leak - namely my late thirties TRF.
I'm surprised grid leak was so popular in the USA. Another point made is Triode Mixers are said to be less noisy than enveloped, all inclusive Mixer tubes (where the triode and Hexode are enveloped in one glass tube. Some American sets I think actually used 2 different tubes - one as mixer and one as I.F. Amp.
It wouldn't surprise me if I don't soon have a bash at the Simplex Super X American HAM Receiver. Many others online have built this 3 tube radio. It would be nice to power it up a bit more so you don't need to rely on phones as in the actual design.
Still, in the real world I still have my HMV to string, reassemble and see through to the finished job.
I'm surprised grid leak was so popular in the USA. Another point made is Triode Mixers are said to be less noisy than enveloped, all inclusive Mixer tubes (where the triode and Hexode are enveloped in one glass tube. Some American sets I think actually used 2 different tubes - one as mixer and one as I.F. Amp.
It wouldn't surprise me if I don't soon have a bash at the Simplex Super X American HAM Receiver. Many others online have built this 3 tube radio. It would be nice to power it up a bit more so you don't need to rely on phones as in the actual design.
Still, in the real world I still have my HMV to string, reassemble and see through to the finished job.
