Russian caps of interest

[piano3]

WB has posted the schematic for the right hand triode version here many times.

 

[VT52com]

I'll chech, thanks.

 

[Wavebourn]

There are 3 Gubernator versions. The old version, Gubernator-7, is a triode amp without negative feedbacks, with 4P1L paralleled output tubes. 5W from each pair, in A2. I posted it in the thread "One More 4P1L Amp".
Gubernator-13 and Gubernator-71 are pentode SE amps, with nested feedbacks. I did not post schematics. 30 and 45W per channel respectively, with GU-13 and GK-71 output tubes.

 

[Wavebourn]

WB has posted the schematic for the right hand triode version here many times.

The schematic on the right picture was designed by another member, based on one of my designs.

 

[VT52com]

Thanks for sharing. 30W from a single GU50 )) cool.

 

[Wavebourn]

Thanks for sharing. 30W from a single GU50 )) cool.

No, 30W from a single GU-13, 45W from GK-71. 10-20W from GU-50. You don't want it running red, socket and solder would not like that.

 

[VT52com]

Hah!

 

[RajkoM]

Polystyrene is my favorite capacitor, but this is russian K72 teflon capacitor with an iron enclosure removed, for the RIAA network.

 

[VT52com]

Is that actual copper foil, or copper plated alu?

 

[RajkoM]

Copper foil from xover foil inductor. Under foil is a transformer isolation paper for better alignment.
Sorry for delay, I have not been active in the last few days.

 

[spaceistheplace]

This might be a good time to inquire-

For those using these kinds of capacitors with steel casing, or for those who remove the steel casing and replace with foil as above-

Do you ground the casing and if so how?

I imagine the RF rejection of the copper foil in the example above is not very effective without a path to ground?

I imagine in general steel casings would be asking for RF pickup, resulting perhaps in oscillation issues.

 

[Wavebourn]

RF injection is not the main problem, moisture injection is. That's why they were sealed.

 

[spaceistheplace]

I’m not against them being sealed.

I’m also not implying what issue is the “main” issue.

Please reread my question.

 

[sumotan]

Hi RajkoM

May I ask, when you remove the K72 from the can, how are the lead attached ?

Thks

 

[RajkoM]

Each lead is pushed about half a centimeter into the center of the cap. And silvered litz wire (from electrodes) was sold for it. Carefully pull the lead out with pliers.
Each litz wire is about 1,5 cm long. That's enough to leads completely goes out

 

[sumotan]

Many thks RajKom

 

[RajkoM]

YAW

 

[rdf]

Zombie thread resurrection, are Russian Ebay caps advertised as polystyrene the real deal? In particular the k71-4, they seem small for the dielectric claimed. Thanks.

 

[wolf_teeth]

IIRC, these are an inch in diameter, and about the right size for a 1uF styrene.
I've thought about them too...
Wolf

 

[rdf]

Thanks. The pic bellow is an old 22 nF polystyrene which I recall has a much lower voltage rating. Maybe the size disparity is the difference between foil and metalized?