"The phone is a remarkably complex, simple device, and very rarely ever needs repairs, once you fix them." - Dan/Panther
Started by Owain, January 29, 2012, 10:21:34 AM
Quote from: twocvbloke on August 20, 2013, 10:57:28 AMI recall seeing this exchange a few years back, looks quite intriguing, but beyond my abilities to construct, it would be interesting seeing one built though...
Quote from: Owain on August 20, 2013, 05:45:30 PMIIRC when the original article was published, 'old' phones (probably Bakelite 300 series!) could be had for about £3 and 'new' phones (probably 706) about £5.
Quote from: Owain on August 23, 2013, 06:27:04 AMYou probably don't need anything like 90V to ring the bells over short lines.
QuoteA 70V/100V line output Public Address amplifier fed by a sine wave audio signal generator will give you a correct frequency. At 70V line a 2500 ohm load corresponds to 2 watts, so you don't need a big amp. 30-40 watt PA amps with nice chunky MOSFETS are pretty cheap second-hand.
Quote from: GTC on August 23, 2013, 11:42:17 AM^ Well spotted, thanks. Sounds like a neat solution for me -- if they work!I've just ordered some. I note from Googling around that they were manufactured in Israel in 1996. Can't locate a datasheet online, so have asked the seller if he can provide.