Help identifying tube: EZ35, 6X5GT or U147

Clever people,

 

I recently ordered and received a batch of 6X5GT tubes for my RIAA.

All were easily identifiable by structure, writing, branding or boxing. But one stood out.

It's marked '6X5GT' and 'Made in Germany' in the writing on the glass.

The base of the tube has the following text: 'Electronic Tube. Made to Specifications' - next to what I think is a somewhat worn-out General Electric.

Would love to hear your opinions on what type it is. And additional info would be appreciated as well, e.g. estimated age?

Thanks in advance,

Kasper

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Clever people,

 

I recently ordered and received a batch of 6X5GT tubes for my RIAA from Japanese Leben.

All were easily identifiable by structure, writing, branding or boxing. But one stood out.

It's marked '6X5GT' and 'Made in Germany' in the writing on the glass.

The base of the tube has the following text: 'Electronic Tube. Made to Specifications' - next to what I think is a somewhat worn-out General Electric.

Would love to hear your opinions on what type it is. And additional info would be appreciated as well, e.g. estimated age?

Thanks in advance,

Kasper

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EZ35, U147 and 6X5GT are interchangeable "full-wave" rectifiers.

Some have an inline outer structure and some have the two parts at right angles as per your example. It's probably better.

See another photo and explination here.

 

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Thank you for the reply, Michael. It's appreciated. And nice to hear the the three types are mutually interchangable.

Taken into account that the text on the tube reads 'Made in Germany' would it be most likely that the tube is an EZ35? Or were 6X5GT with this construction also produced in Europe?

To me it looks identical to the Mullards & Haltrons under the EZ35 here on Radiomusuem.

In regards to your point regardring which construction is better, the NOS tube my RIAA came with is a Hytron one with double plates, so that seems what Leben seems to favour.

Thanks again,

Kasper

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Mullard was really UK Philips from 1928.

Many European tubes with European designation were actually RCA or Sylvania designs, especially the original nickle filament B7G 1.4V 50mA tubes and the earlier larger 1.4V tubes, even if they had a different base. The 25mA tungsten B7G 1.4V valves were a Philips design.
Some of the other European tube makers were also Philips owned.

The construction change might increase anode to anode isolation or power limits. However, it's only a rectifier, so as long as it works it will have no effect on the equipment signal quality.

There may even be USA maker 6X5GT with both kinds of construction made in different times. RCA certainly changed some octal tubes from pinch bases with wires to button base with thin pins soldered into a flat octal base and a metal collar added. Later octal such as 6146 are button base. It reduces series inductance, which is important for VHF.

This article tangentially discusses USA vs European part numbers and developments.

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"Taken into account that the text on the tube reads 'Made in Germany' would it be most likely that the tube is an EZ35? Or were 6X5GT with this construction also produced in Europe?"

Short answer. Maybe and it's only of incidental interest to tube historians. Early EZ35 models may even have been imported and re-marked USA tubes. Mullard did this even before WWII. During WWII the imported tubes were not re-marked.

GE may have had European plants after 1945. They made transistor radios in Shannon, Ireland for a while in the 1960s for export to USA rather than Europe.

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I'm having a bit of trouble figuring out how to quote, but hank you for the exented & insightful response, Michael.

It was exactly informatioin / knowledge like this I was after :)

I'll try and get my hands on an EZ35 with European provenance in the near future.

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