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General Vintage Technology Discussions For general discussions about vintage radio and other vintage electronics etc. |
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11th Jul 2021, 12:28 pm | #1 |
Heptode
Join Date: Dec 2003
Location: South Yorkshire, UK.
Posts: 900
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Mullard Filters ?
I have been giving a pair of Mullard filters but no nothing about them or there purpose. I guessing from the numbers on the dial they are in the audio range. Does anyone have any ideas what these may have been used for. For the size they are very heavy and look to be designed for rack mounting. The also have Jack sockets on either side of the tuning control
Thanks regards Chris
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11th Jul 2021, 12:59 pm | #2 |
Moderator
Join Date: Mar 2012
Location: Fife, Scotland, UK.
Posts: 22,798
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Re: Mullard Filters ?
HP on the plate almost certainly mean High Pass, and the lowest switch setting looks to be around 400Hz, so any audio which gets past it isn't going to be much fun telephone networks traditionally ran 300Hz highpass to define the lower limits of a channel.
I wonder what it was for... David
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11th Jul 2021, 1:13 pm | #3 |
Nonode
Join Date: Oct 2010
Location: Tintinara, South Australia, Australia
Posts: 2,324
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Re: Mullard Filters ?
Advert in Electronic Engineering June 1954 on the world radio history site.
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11th Jul 2021, 9:07 pm | #4 |
Heptode
Join Date: Dec 2003
Location: South Yorkshire, UK.
Posts: 900
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Re: Mullard Filters ?
Thanks for the information that made a interesting read. I have two of these built like battleships. Unfortunately like any specialist kit I cannot think of a use for them. It may be useful to do a frequency sweep for interest.
Thanks regards Chris
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