Hoffman Amplifiers Tube Amplifier Forum

Amp Stuff => Tube Amp Building - Tweaks - Repairs => Topic started by: kasperbergholt on May 10, 2024, 05:45:22 am

Title: Is this an EZ35 tube?
Post by: kasperbergholt on May 10, 2024, 05:45:22 am
Clever people,


Ordered a batch of 6X5GT rectifier tubes from Tung-Sol, RCA and General Electric for a Leben RIAA (RS30EQ (https://bergholt.net/6x5-tubes)). There seems to be at least 3 different construction types - most small 'fat' ones with one plate - and some with two plates.

One of the tubes is marked as 'Produced in Germany' and looks a lot like an EZ35 (https://www.radiomuseum.org/tubes/tube_ez35.html) tube - 1,5 centimeters taller than the smaller ones - similar to some of the Mullards & Haltrons that turn up in Google's image search results.

Does it look like an EZ35 to you?

(https://bergholt.net/wp-content/uploads/2024/05/500-pixels-general-electric-ez35-retifier-tube.jpg)

And a photo of the most common kind of construction in the batch:

(https://bergholt.net/wp-content/uploads/2024/05/500-pixels-tung-sol-rectifier-tube-for-leben.jpg)

Thanks in advance :)
Title: Re: Is this an EZ35 tube
Post by: j-b-c on May 10, 2024, 06:44:20 am
U147 ==> http://www.r-type.org/exhib/aaa0677.htm

Sensibly equivalent to: 6X5GT EZ35 U70
Title: Re: Is this an EZ35 tube
Post by: kasperbergholt on May 10, 2024, 07:50:40 am
Quote from: j-b-c on May 10, 2024, 06:44:20 am
U147 ==> http://www.r-type.org/exhib/aaa0677.htm

Sensibly equivalent to: 6X5GT EZ35 U70

Thanks! What makes you think U147 instead of EZ35 (or a native 6X5GT)? Were U147s produced in Germany?
Title: Re: Is this an EZ35 tube
Post by: j-b-c on May 10, 2024, 08:01:55 am
Quote
Thanks! What makes you think U147 instead of EZ35 (or a native 6X5GT)? Were U147s produced in Germany?

The envelope size, the micas and the plate structure.

Quote
Were U147s produced in Germany?

Which Germany?  What was Germany (or Europe for that matter) when this valve was manufactured?
Title: Re: Is this an EZ35 tube?
Post by: mresistor on May 10, 2024, 08:25:27 am
Better pictures of the Marconi U147 in the top photo showing the printed words on the tube base and glass would be helpful.


Do any of the shorter versions have "Made in Germany" printed on them?
Title: Re: Is this an EZ35 tube?
Post by: kasperbergholt on May 10, 2024, 11:17:06 am
Quote from: mresistor on May 10, 2024, 08:25:27 am
Better pictures of the Marconi U147 in the top photo showing the printed words on the tube base and glass would be helpful.
Do any of the shorter versions have "Made in Germany" printed on them?

All the shorter versions are marked 'Made in the US'.

Here's a photo of the tube's opposite side. Sorry for not including it in the first post.

(https://bergholt.net/wp-content/uploads/2024/05/ez35-2-scaled.jpg)

Text on the tube base reads: Electronic tube. Made to CGE specifications and there's a logo slight visible, which I think is General Electric.
Title: Re: Is this an EZ35 tube?
Post by: mresistor on May 10, 2024, 12:00:27 pm
 6X5GT    http://www.r-type.org/exhib/acl0177.htm (http://www.r-type.org/exhib/acl0177.htm)   guess it's a taller 6X5GT
wouldn't the seller have figured this out?  Heres a Mullard that looks alot like it.