01-09-2021, 09:40 AM
Unfortunately vari mu is an impossibility with the construction used in these valves and I'm holding off on any homebrew of front ends until Peter has perfected his system, lazily riding along on the coat tails of others success as I do, I have used Michael Watterson's technique for the twin valve mixer/oscillator with success, but have found that trying to replace the IF amplifier valves with the rod pentodes isn't successful if there's a strong signal present as try as I might there's no happy medium with the standard AGC.
For replacement use in vintage battery sets I'm also trying to build up substitutes on old valve bases, so that should the rare and expensive ever turn up, they can just be plugged straight in, in other words not modifying the actual set. I've managed to do replacement for the DL2 and DAC1 so far successfully.
I think my not altering the circuitry of the set much will probably entail either finding some DF61 or similar, or adapting the base to take the seven pin miniatures, which themselves are beginning to get scarce.
I've got two sets that are waiting for ct8 substitutes hence why so interested, there's a 1939 table radio that I'd prefer to do using the rod pentodes totally as I'd like to have that able to be a daily burner.
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Radio Caroline...
In mid Norfolk it comes in well, but receiving it from south Notts there is I think an Albanian station that you can hear sometimes, in both locations you can hear the whistle from that most of the time.
The same applies to BBC R Scotland good signal but at night there's a Spanish station that muscles in at 180°. People think I'm mad: I have a large piece of aluminium foil covered card on the south facing wall of my bedroom here! It works quite well screening the unwanted signals...
For replacement use in vintage battery sets I'm also trying to build up substitutes on old valve bases, so that should the rare and expensive ever turn up, they can just be plugged straight in, in other words not modifying the actual set. I've managed to do replacement for the DL2 and DAC1 so far successfully.
I think my not altering the circuitry of the set much will probably entail either finding some DF61 or similar, or adapting the base to take the seven pin miniatures, which themselves are beginning to get scarce.
I've got two sets that are waiting for ct8 substitutes hence why so interested, there's a 1939 table radio that I'd prefer to do using the rod pentodes totally as I'd like to have that able to be a daily burner.
**********
Radio Caroline...
In mid Norfolk it comes in well, but receiving it from south Notts there is I think an Albanian station that you can hear sometimes, in both locations you can hear the whistle from that most of the time.
The same applies to BBC R Scotland good signal but at night there's a Spanish station that muscles in at 180°. People think I'm mad: I have a large piece of aluminium foil covered card on the south facing wall of my bedroom here! It works quite well screening the unwanted signals...
