Hi All again. First thanks for the guy's who gave me the advice on my AWA 712C. needs a bit more but works ok.

Today I bought a console radio, with 6 valves & a three gang variable condenser, it has great potential.

But, I do not know the make or model as it has no badges or name and no model number displayed. I was told by the seller that it may be a S.T.C. radio possibly 1930's to 1950.
I have attached some photos for all to see and I hope maybe someone can help me with a schematic etc.
I have tried Radio Museum but to no good, i'm in the dark on this one. There was a chap I saw today who posted on Vintage Radio an STC model 780B CH-780B which look very similar on the inside of mine with the same shaped dial glass. Maybe you know what it is.

The valves that are in this unit are 5Z4G, 6J8, 6V6G, 3 x 6SKGT

Kind regards.
Hammer_651

It would also pay to list the valve compliment, not all had, the same ones.

STC did strange things with their model numbers.

I have a 1940s bakelite mantle that my late Mum acquired new during WW2.
It is nothing like the stenciled model number and the circuit of it doesn't appear anywhere.

Somethings not right; I would expect 6K7GT by two and something like 6B8 or similar triode, or pentode with two separate diodes within.

I am of the opinion that this has been got at and contains wrong valves.

It could be a 1936, 61, BC only, or 62 DW with wrong valves and if it is a console or not makes a difference as does it having SW or not.

6A8 was superseded by 6J8 in SW sets, albeit both will work in one another's socket with varying results. 1st AF is 6Q7


The more probable alternatives are:

1947 361 Chassis 361K, 6K8G, 2 by 6K7G, 6B6G, 6V6G, 5Z4G. AC, TW Console

1947 262 Chassis 262H, 6J8GA, 2 by 6K7G, 6B8G, 6L6G, 5Z4G AC, DW Console

If you look at the patent dates on the speaker if its original that will also be a clue

It's not unusual to come across radios that have random valves plonked into them by clueless people who want to fill up the sockets.

Here are some STC consoles with 5Z4 rectifiers. Model no is 3rd column, after year:

STC 1936 613 61 AC BC Con. 5Z4 6K7 6A8 6K7 6Q7 6F6
STC 1938 601C 601 AC BC Con. 5Z4G 6U7G 6A8G 6U7G 6B8G 6F6G
STC 1938 601D 601 AC BC Con. 5Z4G 6U7G 6A8G 6U7G 6B8G 6F6G
STC 1938 621C 621 AC DW Con. 5Z4G 6U7G 6A8G 6U7G 6B8G 6F6G
STC 1938 621D 621 AC DW Con. 5Z4G 6U7G 6A8G 6U7G 6B8G 6F6G
STC 1938 630Q 630 AC TW Con. 5Z4G 6U7G 6A8G 6U7G 6B8G 6F6G 6T5
STC 1938 630X 630 AC TW Con. 5Z4G 6U7G 6A8G 6U7G 6B8G 6F6G 6T5
STC 1939 635J 635 AC TW Con. 5Z4G 6U7G 6K8G 6U7G 6Q7G 6AG6G 6T5
STC 1939 635U 635 AC TW Con. 5Z4G 6U7G 6K8G 6U7G 6Q7G 6AG6G 6T5
STC 1947 262H 262 AC DW Con. 5Z4G 6J8GA 2x6K7G 6B8G 6L6G
STC 1947 361K 361 AC TW Con. 5Z4G 6K8G 2x6K7G 6B6G 6V6G

Hi GTC & Marcc. Thanks for the replies. The valve sequence that was on the chassis is from left to right looking from the rear, 5Z4G, 6V6, 6SK7, 6SK7, 6J8 and a 6SJ7. As you say GTC maybe someone did fill up the sockets. I will try to check the model numbers on Radio Museum, see how I go.

Marcc I was lucky in that the patent details were still there although some what faded. Not sure how to read them, can you help.
Here they are: 12K speaker patent information. 14.964/34/80/18/108/3? paper torn at this point then 110,24,101,218,36,110,265,39.
followed by R'd Design No 24,696. the rest is about delivery of item etc.

I have started to draw a schematic and should be finished soon. It is a very neat little unit. Thank you both for your input.
regards.
Paul.P.

Valve lineups are seen here:
https://hrsasa.asn.au/downloads/files/aa_radio-models.pdf
I've had a look but can't find yours. That said a list like this is a bit dazzling with my old eyes and I wasn't sure that the search was working properly - it didn't highlight finds. Also some models don't have a line-up here.
Nevertheless couldn't find that STC used 6SJ7 at all.

Is your line-up from actual valves or a lable? STC radio chassis usually have a paper lable with the chassis-top layout and valve lineup together with the model number and serial number.

Good luck.

That and AORSMs is also where I looked. 6K7 and 6SJ7 are different in that one has a top cap and the other hasn't, so if there are fly leads coming out of cans & nothing to put them on, that's a clue to wrong tubes. Signal grid of 6SK7and 6SJ7 is pin4 not a top cap.

I still think we are missing a 2nd detector 1st audio either a duo-diode triode, or duo diode pentode. Only in a set early on, would I see a pentode 2nd detector. 6J8 is I believe, from around 1938.

Do pay attention to pin ones. If it uses "Goat" shields, or metal type tubes, pin one is normally grounded. That is the shield pin on most but not all metal tubes.


We await the circuit.