Another mystery RCA (?) mixer

[CalavoBob]

Does anyone recognize this vintage tube mixer that was brought into my shop this week? It looks a lot like an RCA that I worked on about 5 years ago, but this one has no manufacturer's name or number anywhere on the casing or the chassis. The VU meter was made by Amplifier Company of America. There are 3 mic inputs, two phono inputs and one "radio" input. ( I though us audio guys were trying to keep radio OUT of our mixes). The three large round audio transformers which can be seen behind the front panel in the first photo are labeled 900542-501. The tubes are regular octal sockets and are 6SN7, 6SC7, 6SJ7, 6K6, and a 5Y3 rectifier. It's entirely possible that these are not the original types though since there are no markings anywhere on this mixer. If someone recognizes this please let me know the make and model number so I can start searching for any kind of a schematic for it. The whole thing has been cannibalized with chopped wiring buses, dangling wires and switches, changed I/O connectors, replaced transformers, caps and resistors, you name it. Its all rat's nets point to point wiring, so any kind of schematic could save me days. It looks cool though.

 

[emrr]

I'm gonna say this was home made. I've seen a couple of their things pop up over time from Amplifier Company of America, but I think this is just a salvaged meter they used. The wood case is like what RCA used pre-war in the late 1930's for desk mounted custom passive mixer panels, and the 3 stripes on top seals it (to me) as a repurposed RCA case, as they styled that way for a bit. The audio iron is post-war RCA, but this is definitely not an RCA product. Radio station guys did a lot of this sort of repurposing of old bits. The recent cap job is with parts from Antique Audio Supply, last 5 years.

 

[Johnny1234]

I agree with emrr. Much of the the old AM radio gear was designed in house for their custom needs. Especially small independent owner stations.