victor: Columbus

Hi, I have reciently refurbished an Italian  Columbus radio and know that the rear view you are showing in your group of three photos of the Colunbus radio is incorrect. The valves used in the Columbus  radio are not octal valves but are the U series European style valves, the back panel is held on using 4 corner screws, there are only two screw positions in the rear view photo, the phono pick up shown in the rear view with the back attached is not shown on the rear view with the back removed. No phono connections in the chassis.  The mains voltage adjustment switch on the columbus is round and seen in the rear view photo withy the back attached, the photo showing the rear view with back removed has a different style of mains voltage adjustment switch. Hope this information helps in selecting the correct photo. I would appreciate a copy of the circuit for this Italian Columbus radio if one is available.

Alan Bidwell

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U series means only 100mA Series operation and can be any base (in theory). The photo looks like rimlock = B8A, but U series is also common on B9A / Noval base,  Europe side contact base P (P8A), German Y8 and International Octal isn't so common but was used for U series. Probably not Mazda Octal as it died off maybe by 1942.

You can suggest change to valve / tube list if you know them and you are sure it's the same model. It wasn't uncommon 1939 to 1953 for the same basic radio, sometimes in same or similar cabinet in Europe to sequentially have P8 or Mazda Octal, then imported USA Octal, then Philips Octal, then Rimlock. Some UK makes used Octal when rimlock was common in parts of Europe and then Rimlock when USA was using B7G and Noval/B9A already existed. There is quite an overlap 1950s of Octal, Rimlock and Noval/B9A use.

P8 and Mazda octal pretty rare after 1942.

Rimlock / B8A is sort of a philips idea of a shrunken Sylvania Loctal button base. But really the 9th pin was needed to dispense with top cap on some Loctal and Octal types, so the 10 position 9 pin base needing no key or pip replaced Y8, Octal, Loctal-8, Rimlock/B8A. For a short while Philips/Mullard in 1945 re-issued many P5, P7 and P8A valves with Octal bases, but these quickly replaced with B7G for battery and B8A/Rimlock for mains, later Noval/B9A. A few battery valves used rimlock, the DK40 seeing service in otherwise B7G base battery radio as it was superior to 1R5/DK91. It was replaced by DK92. A mains triode-hexode really needs nine pin or 8 + top cap, but one triode-hexode was shoehorned into B7G by connecting cathode to one side of heater and making the triode osc / mixer grid connection internally.

EDIT:

I agree the back obviously is off some other set and the chassis can't accomodate Octal. I'd be  nearly sure that they are rimlock/B8A and I'd guess similar selection to a DAC90a.

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Yes I see that they are not octal valves but that is not the point that I am trying to make, the photo showing the back of the radio with the back panel removed revealing the chassis and valves is not the case and chassis that belongs to the Columbus radio. The rear view and the front view of the complete set is correct. I will take a photo of the rear view of my set. ( I dont know how to attach the photo)

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Use Menu

Updates & Questions

On the Model page.

There should be:

1. 3/4 angled view of front (slight amount of side and top visible, not straight)
2. Close up of tuning scale
3. straight views of rear cover on and off
4. If possible, top and underside views of chassis.

These should be evenly lit, no lamp or sunlight reflections and high resolution, up to 1400 wide and 2100 high, certainly no less than 930 wide.

 

The Model will then also appear in your collection page. You get points per photo.

Use Menu

Updates & Questions  Data Change etc.

On the Model page to suggest the correct list of valves.(you get points for that too)

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