iampoor1
Well-known member
Really old vactrols, anyone have any data or recognize them?
https://imgur.com/a/xiq6vdl
https://imgur.com/a/xiq6vdl
Anyone recognize these really old vactrols?
- Thread starter iampoor1
- Start date
Help Support GroupDIY Audio Forum:
I have seen Vactec before, might have one in a drawer. If I recall correctly they were used in some odd CBS piece. Might have an incandescent bulb inside?
iampoor1
Well-known member
mjrippe said:
Cool. I'm under the impression that there were only made for a few years (if that). Looks to have an LED inside believe it or not (i originally assumed incadescant bulb as well). I messed around with one of them today and found a 1.45v forward voltage across two of the pins on my multimeters diode check mode. When flipping the probes...nithing. so it's either two diodes in series with an incadescant bulb...or a REALLY old Led, as these have a date code of 1973. ;D
Hello,
I remember to have encountered some VACTROL's ( with this same look ) in a SONTEC EQ ( model 430 ? ) , that I fixed a few years ago.
It was a bulb inside, not a LED.
They were used as a silent By-Pass switch.
Several bulbs were dead, I opened the can and replaced the bulbs, and back in business
Best,
Guy
I remember to have encountered some VACTROL's ( with this same look ) in a SONTEC EQ ( model 430 ? ) , that I fixed a few years ago.
It was a bulb inside, not a LED.
They were used as a silent By-Pass switch.
Several bulbs were dead, I opened the can and replaced the bulbs, and back in business
Best,
Guy
The 21L... designation was used for OEM parts. I have numerous Electronic Engineering Master Catalogs from the 60’s and 70’s and nowhere are specs/info on 21L series listed. Off the shelf parts would have had the VTL prefix. There’s a good chance they’re just renamed stock parts, but Vactec did custom parts for OEMs as well. I’ve pulled 21L parts in both the metal cans and the familiar plastic 4 lead types from all sorts of stuff - Altec mixers, Conn Organs, Hammond organs etc. The metal cans can contain LED, incandescent or neon light sources.
So bottom line, you can’t tell much about those from their housing type or OEM part number. You just have to do a proctology exam and see what you come up with.
Scan from 1973 EE Master attached, just because.
So bottom line, you can’t tell much about those from their housing type or OEM part number. You just have to do a proctology exam and see what you come up with.
Scan from 1973 EE Master attached, just because.
