Need info on: Spencer-Kennedy Labs Variable Filter model 302

GroupDIY Audio Forum

Help Support GroupDIY Audio Forum:

This site may earn a commission from merchant affiliate links, including eBay, Amazon, and others.

VacuumVoodoo

Well-known member
Joined
Jun 3, 2004
Messages
218
Location
Gothenburg, Sweden
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

orig.jpg

orig.jpg

orig.jpg

orig.jpg

orig.jpg

orig.jpg
 
[quote author="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.
[/quote]

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

My HP333 distortion analyzer uses such one too..

Jakob E.
 

Latest posts

Back
Top