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USE Gulbransen model A1 - Printable Version

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USE Gulbransen model A1 - Philconut - 03-03-2023

Hello,
Can anyone help me with a circuit for a USA made Gulbransen model A1 7 valve plus magic eye wireless. 6K7, 6C5, 6K7, 6H6, 6F5, 6F6, 5Y3, 6U5. This set was made for the New Zealand market & one has ended up on my bench for a significant overhaul. The set is unique in that the dial does not have a pointer but a travelling light behind the glass that illuminates the markings through the glass. Normally, I would take the circuit from the chassis but this set has been badly altered and, as well, the oscillator coil, which has a separate 6C5, seems to be unusually complicated.
Any help would be much appreciated.

Regards
John

RE: USE Gulbransen model A1 - MrFixr55 - 03-03-2023

Hi Philconut,
Gulbranson is a piano and organ company that bought the Wells Gardner & Company in the early 1930s.

I have searched Nostalgia Air under both Wells Gardner and Gulbranson, but cannot find this model. The radio does show up in "RadioAttic, a seller of radios. The owner's name and phone # shows up there. You may be able to contact them to see if they are willing to sell you a schematic (or be real kind and give you a copy.
https://radioattic.com/item.htm?radio=0961621

From RadioMuseum:
Gulbransen Company; 816 North Kedzie Avenue, Chicago, Illinois - Trade names Champion Jr., Gulbransen. According to "The Music Trade Review", September 15, 1928, Gulbransen Company was at 3232 W. Chicago Ave., Chicago. They claimed then to have 1500 radio dealers in an advertisement and state: "In the piano business, Gulbransen has attained leadership that all recognize." Then they sold radios also with franchising outlets - only AC table and console models.
One has to distinguish between Gulbransen in Australia and in the USA.
Gulbransen exportet - for instance to Switzerland.

I did find a schematic under Wells Gardner A1 Series:
http://www.nostalgiaair.org/PagesByModel/503/M0023503.pdf

This is a 3 band radio with a similar tube lineup (a 6SJ7 and 6SK7 have the same pinouts, it is just that the 6SJ7 is a "sharp cutoff" Pentode while the 6SK7 is a remote cutoff or "super control" Pentode). The chassis does not look like the A1 radio shown in Radio Attic, however, that radio shows a 6Q7 near the 6F6 (If I am reading this correctly). Frankenradios!!

RE: USE Gulbransen model A1 - Arran - 03-03-2023

Posting a photo of the chassis may help, but if it's like the Radio Attic set it looks like it could be either a Wells Gardner, a Continental (later Admiral) or a Belmont, those were the big three in Chicago that manufactured private label radios for stores, with a few being made by Stewart Warner (particularly for Sears), but I don't think it's one of those. By the styling, and double ended octal tube choices, and inclusion of a 6H6 double diode, I would call it either a 1937 or 38 model. Does it have a glass dial or a plastic one? Lighted pointer from the rear are unusual, Rogers used them in a number of their sets, particularly Deforest-Crosley, in the U.S American Bosch, Midwest, Majestic (post 1934), and I believe Scott also used them. 
Regards
Arran

RE: USE Gulbransen model A1 - Philconut - 03-03-2023

Many thanks, I'll follow this up.

Cheers
John

RE: USE Gulbransen model A1 - Philconut - 03-03-2023

THe dial is glass & in very good order fortunately.

RE: USE Gulbransen model A1 - Philconut - 03-03-2023

Perfect! The Wells-Gardner circuit is the correct one. Thank you for the information.
Cheers
John

RE: USE Gulbransen model A1 - MrFixr55 - 03-04-2023

I figured that the Wells Gardiner should be the one. In the Radio Attic Pic, there is a big W/G toward the bottom of the dial. Does yours look like this?

The chassis doesn't look the same but companies usually use the same circuit, even on different models.

RE: USE Gulbransen model A1 - MrFixr55 - 03-04-2023

@ Arran, I have an RCA 5T7 ca 1936 -7 that has a similar scheme, green pointer for BC, red pointer for SW. However, the dial is rather small and not as exciting as a Zenith Big Black Dial or others.

RE: USE Gulbransen model A1 - Arran - 03-05-2023

Quote " @ Arran, I have an RCA 5T7 ca 1936 -7 that has a similar scheme, green pointer for BC, red pointer for SW. However, the dial is rather small and not as exciting as a Zenith Big Black Dial or others." 
 
 I rather like the way that RCA sets were built in that era, unfortunately they do suffer from power supply failures more then their earlier sets, not as bad as the early 40s Brand Z sets though. RCA, and in Canadian GE, and others seemed to like using that tube lineup, it was completely unnecessary to separate the detector, and AVC diodes from the first audio triode but it allowed them to market a five tube set as a six tube without adding anything but an extra socket. Sometimes they would tie the two diodes in the 6H6 together or ground out one of them. I noticed they stopped doing this shortly after that scandal erupted about companies like International Kadette marketing so called "ten tube" radios where three or four of the ten were just ballast tubes, the laws were changed after that. 
Regards
Arran