Sovtek 5Y3GT and Sovtek 5V4G?

[catnine]

Right now I have the 5Y3 sovtek in my 6G2/5E3 fixed bias build. I have 408 VDC on the plates. I know the sovteks run higher than NOS rect tubes.

I also have a sovtek 5V4G. My reservoir cap is 30uf and it's been a few years without issue with the 5Y3 .

from what have been able to find the 5V4G , this is what the sovtek glass is marked the other side is 5U4C. From what I've read the 5V4G will raise the voltage but I can't find specs and also can't find what size reservoir cap a 5V4G can handle. all I could find were old tube charts showing a 5V4 25v@174mA and a 5Y3 50v @125mA but I can't say this applies to these modern new sovteks . I have read of people placing 5V4's in champs and 5E3's .

Does anyone have better info ?

[tubeswell]

Try Here - no promises

Frank's electron Tube Data sheets

[catnine]

It's very confusing to me these charts. They talk about max AC plate voltage and max DC output and mA draw and the input impedenace 100 ohms and if you are using a Cap input greater than 40uf then you might want to raise the input impedenace . The charts show 8UF .

It seems that a 5Y3GT or 5V4G are limited and almost near their limit when using a cap when the max ac plate is 375 volts per plate when some PT's are at 330 volt AC yet a champ my draw 40 mA and a 5E3 80mA .

Can't say I understand much if any of this . The 5V4G is a max DC mA of 175mA so I assume it's safe there . I would imagine the total mA dc draw would affect how much the rect tube is stressed by using a 30uf reservoir cap . Well maybe .

[Bruce / Mission Amps]

The SOVTEK 5Y3GT is actually closer to a GZ30 rectifier tube.
The GZ30 is a slowish start up, indirectly heated cathode, lower, (125ma) current rating rectifier tube, similar to a small GZ34.
I've used them with 33uF to 47uF filter caps many times and if I was worried about the inrush current I just stick a 2 watt 47 ohm resistor in series, in front, of the first filter cap.
The Russian SOVTEK 5Y3GT and a real vintage, American made 5Y3GT are not the same tube at all. Don't try to interchange them without considering the differences in B+ voltages.
The 5V4, 5V4G etc is a different tube but it has similar characteristics of the GZ30 too.
Don't be confused by the inked nomenclatures on the Russian tubes as having any relevancy to American made tubes from days gone by.

The numbers and letters "5u4c" seen on Russian tubes DO NOT mean 5U4C, 5U4 (G, B) or 5V4 or anything of the sort...
Those letters, U u and C c are Russian Cyrillic letter/characters, not English letters.

U = Tse (Ц, ц) is the 23rd letter of the Russian alphabet, and is thought to have come from the Hebrew letter Tsadi (צ) (Arabic: Tsad ص‎). It is a letter in the Cyrillic alphabet. It looks somewhat like U with square corners and a "pig tail" on the bottom right. It represents a voiceless alveolar affricate /ts/, like the ts in "cats."

C = Es (С, с) is the eighteenth letter in the Bulgarian, the nineteenth letter in the Russian, and the 21st letter in Serbian Cyrillic alphabet. It resembles the letter <C> in the Latin alphabet, being one of seven letters in the Cyrillic alphabet that share appearances with Latin alphabet letters but are pronounced in a different way (although the Latin alphabet's <C> can have a "soft" pronunciation before front vowels).

[catnine]

Originally Posted by Bruce / Mission Amps

The SOVTEK 5Y3GT is actually closer to a GZ30 rectifier tube.
The GZ30 is a slowish start up, indirectly heated cathode, lower, (125ma) current rating rectifier tube, similar to a small GZ34.
I've used them with 33uF to 47uF filter caps many times and if I was worried about the inrush current I just stick a 2 watt 47 ohm resistor in series, in front, of the first filter cap.
The Russian SOVTEK 5Y3GT and a real vintage, American made 5Y3GT are not the same tube at all. Don't try to interchange them without considering the differences in B+ voltages.
The 5V4, 5V4G etc is a different tube but it has similar characteristics of the GZ30 too.
Don't be confused by the inked nomenclatures on the Russian tubes as having any relevancy to American made tubes from days gone by.

The numbers and letters "5u4c" seen on Russian tubes DO NOT mean 5U4C, 5U4 (G, B) or 5V4 or anything of the sort...
Those letters, U u and C c are Russian Cyrillic letter/characters, not English letters.

U = Tse (Ц, ц) is the 23rd letter of the Russian alphabet, and is thought to have come from the Hebrew letter Tsadi (צ) (Arabic: Tsad ص‎). It is a letter in the Cyrillic alphabet. It looks somewhat like U with square corners and a "pig tail" on the bottom right. It represents a voiceless alveolar affricate /ts/, like the ts in "cats."

C = Es (С, с) is the eighteenth letter in the Bulgarian, the nineteenth letter in the Russian, and the 21st letter in Serbian Cyrillic alphabet. It resembles the letter <C> in the Latin alphabet, being one of seven letters in the Cyrillic alphabet that share appearances with Latin alphabet letters but are pronounced in a different way (although the Latin alphabet's <C> can have a "soft" pronunciation before front vowels).

I was going by one site that sells the sovtek 5V4 calling it a real 5V4 yet the tube i got and it is also stated on the site some may have marking like 5 looks like a U 4C yet on the opposite side of the bottle it is marked sovtek 5V4G.

I used a NOS 5Y3 GT in my 6G2 front end fixed bias 5E3 power section and then needed the NOS for my AA764 champs , I have a sovtek 5Y3GT in this push pull 6V6 build now and once I saw the new 5Y3 I knew it was not the same tube , it raised the B+ 10VDC . I can't say I feel all that secure with this sovtek even though I like the sound which is a bit tighter but don't really trust the sovtek not that it has given me any problems. I have not read about issues with the sovtek 5Y3 other than a higher B+ .

One thing I did notice in the later AA964 princeton used a GZ-34 and a different PT than 6G2 with the same tube compliment other than adding an extra cap and dropping resister before the PI and preamp . Was this to raise the plate VDC for a cleaner tone? My build is now with the sovtek 5Y3 running very near the AA964 voltages with a 409VDC plate. I used an Allen amp TP25 PT for a princeton / Champ which when I got it the site rated it at 325-0-325 @180mA. Now it's rated at 310-0-310 @150Ma.

With my voltages I was thinking of the JJ GZ-34 I have but that would really put me over the top. I guess it's best for me to get a NOS 5Y3GT just for peace of mind .