UK Vintage Radio Repair and Restoration Powered By Google Custom Search Vintage Radio and TV Service Data

Go Back   UK Vintage Radio Repair and Restoration Discussion Forum > General Vintage Technology > General Vintage Technology Discussions

Notices

General Vintage Technology Discussions For general discussions about vintage radio and other vintage electronics etc.

Closed Thread
 
Thread Tools
Old 11th Jul 2021, 12:28 pm   #1
ChristianFletcher
Heptode
 
ChristianFletcher's Avatar
 
Join Date: Dec 2003
Location: South Yorkshire, UK.
Posts: 900
Default 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
Attached Thumbnails
Click image for larger version

Name:	D71FE1A7-27E8-42A2-BD85-FA149E4BDC76.jpg
Views:	135
Size:	81.2 KB
ID:	237459   Click image for larger version

Name:	754270A2-1D02-405F-B9BF-34E3413C95E9.jpeg
Views:	125
Size:	92.5 KB
ID:	237460   Click image for larger version

Name:	F5A61403-1FB9-47EF-B27E-2B4932AD402A.jpeg
Views:	103
Size:	72.0 KB
ID:	237461   Click image for larger version

Name:	CD265472-BE80-44D3-8B69-002A68182CDB.jpeg
Views:	90
Size:	89.5 KB
ID:	237462  
__________________
Every Silver Lining Has Its Cloud https://youtube.com/channel/UCvBpiuUUnErJlNBm6DWb3Ww
ChristianFletcher is offline  
Old 11th Jul 2021, 12:59 pm   #2
Radio Wrangler
Moderator
 
Radio Wrangler's Avatar
 
Join Date: Mar 2012
Location: Fife, Scotland, UK.
Posts: 22,798
Default 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
__________________
Can't afford the volcanic island yet, but the plans for my monorail and the goons' uniforms are done
Radio Wrangler is online now  
Old 11th Jul 2021, 1:13 pm   #3
Terry_VK5TM
Nonode
 
Terry_VK5TM's Avatar
 
Join Date: Oct 2010
Location: Tintinara, South Australia, Australia
Posts: 2,324
Default Re: Mullard Filters ?

Advert in Electronic Engineering June 1954 on the world radio history site.
Attached Thumbnails
Click image for larger version

Name:	filter.jpg
Views:	120
Size:	58.9 KB
ID:	237467  
__________________
Terry VK5TM
https://www.vk5tm.com/
Terry_VK5TM is online now  
Old 11th Jul 2021, 9:07 pm   #4
ChristianFletcher
Heptode
 
ChristianFletcher's Avatar
 
Join Date: Dec 2003
Location: South Yorkshire, UK.
Posts: 900
Default 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
__________________
Every Silver Lining Has Its Cloud https://youtube.com/channel/UCvBpiuUUnErJlNBm6DWb3Ww
ChristianFletcher is offline  
Closed Thread

Thread Tools



All times are GMT +1. The time now is 11:01 am.


All information and advice on this forum is subject to the WARNING AND DISCLAIMER located at https://www.vintage-radio.net/rules.html.
Failure to heed this warning may result in death or serious injury to yourself and/or others.


Powered by vBulletin®
Copyright ©2000 - 2024, vBulletin Solutions, Inc.
Copyright ©2002 - 2023, Paul Stenning.