VacuumVoodoo

Need info on: Spencer-Kennedy Labs Variable Filter model 302
« on: December 15, 2004, 07:26:48 AM »
Hi guys,

does anybody have any info on this filter ? Datasheet, manual or schematic ?
As far as i could find out it's made in early 1960s but the company does not exist anymore.
Got it from a company trading used test instruments as replacement for a faulty multimeter i bought from them.
The unit is in very good condition and working.

Each filter section has 5 Telefunken ECC81/12AT7 and some other stuff in line output amps, see pictures.
What puzzles me is the big black tubular component, i gues it's some kind of multisection wirewound potentiometer. It's operated by the frequency tuning dial.

The thing is a dual filter, HP/LP cutoff frequency tunable 20Hz to 100kHz.

Any help will be greatly appreciated. Below are a few small pictures, you can see full size photos here:
http://www.fototime.com/inv/A2244A5765E01E0

Alex






Alex Niemand
_____________________________________
Life's a party but you get invited only once...
Tubewonder amps
"L


gyraf

Re: Need info on: Spencer-Kennedy Labs Variable Filter model
« Reply #1 on: December 15, 2004, 07:53:27 AM »
Quote from: "VacuumVoodoo"
What puzzles me is the big black tubular component, i gues it's some kind of multisection wirewound potentiometer. It's operated by the frequency tuning dial.


Probably a tuning capacitor - that is the best way to do tuneable filters.

My HP333 distortion analyzer uses such one too..

Jakob E.
..note to self: don't let Harman run your company..


 

Related Topics

  Subject / Started by Replies Last post
6 Replies
2435 Views
Last post November 09, 2008, 04:56:05 PM
by jrfred453
0 Replies
1582 Views
Last post December 13, 2010, 06:10:57 PM
by bobschwenkler
0 Replies
788 Views
Last post November 23, 2018, 04:08:45 PM
by squarewave
3 Replies
321 Views
Last post October 21, 2020, 07:04:25 PM
by EmRR