What is this? Western Electric gizmo

[Dusty Circuit]

Hi all!

I just won an auction on ebay.  THIS.
I know it's a filter of some sort and thought it might be fun to play with.

But what is it?

The guy (or gal) states he/she tested it via an amp and a speaker.

Thanks
/D.C

 

[Biasrocks]

Nice score, lot's of great parts in there.

I'm guessing it's frequency generator.

Mark

 

[abbey road d enfer]

Hi all!

I just won an auction on ebay.  THIS.
I know it's a filter of some sort and thought it might be fun to play with.

But what is it?

The guy (or gal) states he/she tested it via an amp and a speaker.

Thanks
/D.C

As the descrittion says and the charts show, this is a switchable one-octave filter. The interesting point is the center frequencies are spread at 1/2 octave intervals. Since it's an LCR passive design, for proper operation, the inputs and outputs must be properly terminated (matched).
I believe this piece of test equipment was used for evaluation or QC of microphone production at the STC (Coles) factory.

 

[Dusty Circuit]

Thanks for the reply.

What do you mean with matched input and outputs?

 

[abbey road d enfer]

Passive circuits expect specific source and load impedances. Failure to provide these will not guarantee proper operation; amount of boost/cut  and center frequency may be out of specs. This info should be written in the manual. Most of the times, 600 ohms is recommended, but Brits sometimes fancied 200...

 

[emrr]

Be sure to get us a clear copy of that schematic, and the part #s of the coils.  A clear picture would be great.  

 

[Dusty Circuit]

Passive circuits expect specific source and load impedances. Failure to provide these will not guarantee proper operation; amount of boost/cut  and center frequency may be out of specs. This info should be written in the manual. Most of the times, 600 ohms is recommended, but Brits sometimes fancied 200...

Ok, i see. Maybe it would be a good idea to buffer these? I would like to run line level signals past it.

emrr: Sure, no problem.

 

[abbey road d enfer]

Passive circuits expect specific source and load impedances. Failure to provide these will not guarantee proper operation; amount of boost/cut  and center frequency may be out of specs. This info should be written in the manual. Most of the times, 600 ohms is recommended, but Brits sometimes fancied 200...

Ok, i see. Maybe it would be a good idea to buffer these? I would like to run line level signals past it.

Most actual circuits are adequate for driving 600R loads (in fact they often present a lower source Z, so you may have to install additional series resistors). Just the same, most actual line inputs are at least 10k, so you may have to load with shunt resistors.

 

[emrr]

It may be the sort of circuit which is relatively unaffected by loading.  Put pink/white noise through it and see how accurate the filters are for various loading conditions.