Any info on a GenRad 1925 "mulitfilter"

[joew]

Howdy!

I found this beast at a recent ham fest and decided I could not live without it. This appears to be that rare spot where real science crosses over to audio.  On the face of it, the machine seems to be a downright funky 1/3 octive EQ with kind of an interesting display.  Rather than the common sliders, it has knurled things for your thumb to move, and they are in turn connected to mechanical moving dots like little old time radio dials.  It also has significantly deeper boots and cut ranges, +/- 25db, and as far as I have been able to tell, it has the outputs from the filters broken out individually, as well as a summation output on the back.  I found some info on the net, but I would to get my hands on a manual.  I found one but the site cert has expired and he wants 50 bucks for it.  Or if you have ever met up with one of these in real life I would be interested in hearing about it.  It is just a marvel of GR craftsmanship.

[Vgkid]

You could try sending an E-mail to IET labs, it is worth a chance.

[The Soulman]

Did you see the original catalog? It has some info.

It's on page 67:
http://www.ietlabs.com/pdf/GR_Catalog/GenRad_Cat-1973.pdf

[Circlotron]

https://www.worldradiohistory.com/Archive-Company-Publications/Archive-General-Radio/GR%20Exp%201968_10.pdf

https://www.worldradiohistory.com/Archive-Company-Publications/Archive-General-Radio/GR%20Exp%201969_05.pdf

[TimFox]

I like the front-panel key lock to stop unauthorized changes in the filter settings.
I remember other students visiting my university lab (at around the time of this catalog) who would be attracted to the thumbwheels as something to twiddle.