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9th Jan 2006, 9:07 pm | #1 |
Octode
Join Date: Jun 2004
Location: Hampton Vale, Peterborough, UK.
Posts: 1,698
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Headphone choice for crystal radios
Yes, folks, I've found yet another gap in my hitherto assumed-to-be encyclopaedic knowledge
Can anyone tell me the best impedance choice for headphones used with a basic crystal radio, such as the ubiquitous Ivalek? Don't all shout at once, please -Tony p.s. My guess is a high-ish 2k or so... |
9th Jan 2006, 9:20 pm | #2 |
Rest in Peace
Join Date: Jul 2004
Location: Dartford, Kent, UK.
Posts: 1,661
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Re: Headphone choice for crystal radios
Hi Tony, Yes high impedance phones work best, The most common type around seems to be the S.G. Brown type "F", which were 2000 ohms per side. Try :-
http://www.webex.net/~skywaves/xtalset102/headsets.htm Or:- http://www.schmarder.com/radios/crystal/ Regards, Mick.. |
9th Jan 2006, 9:34 pm | #3 |
Moderator
Join Date: Jan 2003
Location: Ipswich, Suffolk, IP4, UK.
Posts: 21,288
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Re: Headphone choice for crystal radios
This has been discussed recently in the forums. Take a look at this thread:-
https://www.vintage-radio.net/forum/...ead.php?t=5918 Graham. |
10th Jan 2006, 7:55 pm | #4 |
Octode
Join Date: Jun 2004
Location: Hampton Vale, Peterborough, UK.
Posts: 1,698
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Re: Headphone choice for crystal radios
Thanks for the replies, guys. Useful to know these things! (Even if I forget them almost immediately...)
-Tony |
10th Jan 2006, 10:45 pm | #5 |
Dekatron
Join Date: Jan 2004
Location: Newcastle upon Tyne, Tyne & Wear, UK.
Posts: 8,194
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Re: Headphone choice for crystal radios
Hi Tony, therfe is a circuit on the crystal set site for an amplifier that will allow your to use low Z phones with a crystal set, it's based on a 3 legged beast (unfortunately) , the TL431. It will run at low power and is very small. I actually built a 2, 3 legged thing radio based on this and the Ferranti ZN414 radio chip.
With apologies to all forum members for the profanities !! Ed |
11th Jan 2006, 10:56 am | #6 |
Octode
Join Date: Jun 2004
Location: Hampton Vale, Peterborough, UK.
Posts: 1,698
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Re: Headphone choice for crystal radios
Once again, thanks to all for the useful contributions - all adding to the vast crumbling edifice of knowledge that is Thompson
Particular thanks to you, Mick, for the links to the site showing test comparisons. I never knew there was so much interest in crystal radios! Cheers. -Tony |
11th Jan 2006, 4:03 pm | #7 |
Retired Dormant Member
Join Date: Dec 2005
Posts: 9
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Re: Headphone choice for crystal radios
Hi all,
Diverging slightly from the 2000 Ohms headphone issue, in early vintage we made our own chrystals (if galena wasn't available). A a pea-sized piece of lead was melted in an old teaspoon with a pinch of sulphur stirred in. This was done outside to avoid inhaling the very pungent fumes. It didn't matter if the sulphur caught fire. This resultant rough blob was fitted into the holder and a "cat's whisker" ( a piece of fine steel wire wound into a small spring, the end of which was used to locate a sensitive rectifying area on the chrystal surface.) The coating of "Blue Gillette" razor blades also would rectify. Regards, Les. |
11th Jan 2006, 6:02 pm | #8 |
Retired Dormant Member
Join Date: Apr 2003
Location: Salt Spring Island, BC, Canada
Posts: 368
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Crystal Set Headphones
There was a recent inquiry as to the best headphones for crystal sets. The advice given was in the main useful but for the ultimate in sensitve headphones (and for super selective crystal sets). go to www.crystalradio.net/ and look at the Sound Powered Section.
John. |