13-07-2020, 03:40 PM
Hi.
Progress again and very odd to boot.
I have a tape head demagnetiser.......... Somewhere. So I found a wound coil with a suitable hole in it for a 6mm Allen key. I connected it to 45vac and it gave a really strong pull. I then degaussed the audio valve and after ward the output nearly doubled. So the 1J42A appears to be effected by magnetism. Take one even a foot away from a mains transformer and it buzzes through the phones far more than any other valve I know, I'm not saying that it's the reason for the residual magnetism as they are stored near a speaker.
Performance isn't as good as before but at least it's much better.
Progress again and very odd to boot.
I have a tape head demagnetiser.......... Somewhere. So I found a wound coil with a suitable hole in it for a 6mm Allen key. I connected it to 45vac and it gave a really strong pull. I then degaussed the audio valve and after ward the output nearly doubled. So the 1J42A appears to be effected by magnetism. Take one even a foot away from a mains transformer and it buzzes through the phones far more than any other valve I know, I'm not saying that it's the reason for the residual magnetism as they are stored near a speaker.
Performance isn't as good as before but at least it's much better.
