Quote:
Originally Posted by Spencervs
Ahh hang on, just looked into things a little and older magnetic phones were of higher impedance to our modern equivalents. So this must be why? That would make sense. Now I'm wondering where to find some suitable headphones!
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They are magnetic and were typically 2,000 Ohms impedance.
(Not to be confused with 'crystal earpieces').
Sometimes they're 1,000 Ohm wire in series, sometimes both are 2000 Ohms wired in parallel.
They crop up from time to time often not tested and found to be in need of rewinding doe to 'green spot' corrosion
There are two coils on a 'pole-piece' in each earphone. Sometimes just one of the four will be defective.
They can be rewound by hand, but it's a bit tedious and that takes you down another 'rabbit hole' away from your 'Ocean Hopper' project.
Best to buy a tested pair, but they're not especially cheap. There's a pair for sale here:
https://www.amateurradiosales.co.uk/...hones-2000-ohm
Two pairs untested here 'Buy it Now/Make an Offer':
https://www.ebay.co.uk/itm/363894979...IAAOSwcXxh~69l
Maybe a forum member has some they'd be willing to part with?