New Project - lots of work

[timford]

Picked this up recently for $150. Hasn't worked for 10 years apparently when it was brought to australia and damaged in transit.

So far all I've done is pull it open and am working on the schematic and learning about the tubes and field coil speaker.

As I go through I will be asking specific questions as separate topics.

Not sure if it has ever been worked on before by the look of it. I'm going to be testing the RCA 6v6GTAs in another amp and getting spares of just about everything. Need to get a decent multimeter and a variac, and a few other bits and pieces. Considering putting in an IEC and a small drop down transformer that I can chassis mount so I don't have to worry about anyone running it at the wrong voltage. It is that beat up that I'm not worried about keeping it pure vintage. I would like to keep the field coil speaker though, all going well.

Have a look and if you have thoughts, put them out there.

Pics were taken by my 8yo. Wife has a Nikon D3, and I'll be getting her to take a heap of pictures before I start pulling things apart.

[timford]

Schematic and 1 more pic.

[timford]

In the schematic I've tried to get a few things to match the actual wiring pattern rather than being the neatest, especially with the 7a7. I'll come back to it next week and have another go at making a prettier one.

[leadfootdriver]

Those TUBULAR CONDENSER caps are the bomb!

Nice find. You can paint the chassis with some rust killer paint, or go the full monty and get it dipped. You'll need to paint it after that for sure, but with a heavy primer, you could get it flat. OR powder coat.

[Cantplay]

LOVE the grill.

John

[timford]

I've got some nice light colored, high quality grill cloth that will look similar to what it apparently came out with 70 years ago. Joined radiomuseum.org just so I can get more information on some of the old tubes. Most seem to have been common in old car radios, and other radios.

7a7 pentode front end.
76 low gain single triode PI (5 pin socket)
80 Rectifier (4 pin socket)

And then the 6v6s.

The field coil also uses a 5 pin socket and it was really interesting putting everything together in the schematic to see how it all fitted together. The field coil speaker makes much more sense now.