Russian transmitting tubes

[kb3ouk]

Anyone have any experience with either the GK71, GU13, or GM70? The GU13 is almost identical to an 813. The GK71 is basically a GU13 that is a true pentode (has a suppressor grid, not beam plates). The GM70 appears to share the same plate structure as the GK71/GU13, but is a triode with no plate cap, plate is fed through the base.

[KE6DF]

The GM70 is similar to a beefed up 845.

There is a yahoo GM70 group that I'm in. Most of the discussions center around using them for SE triode audio amps.

Apparently, they work well in those apps. They also would probably make good PP modulators or drivers for big class B tubes like 833's.

The nice thing about them are they are cheap -- at least relative to 845s -- about $25 on epay.

A bad thing is sockets are hard to come buy, but usually can be found on epay. Also they have 20 volt filaments at 3amps. (much higher emission than 845s).

Dave

[kb3ouk]

The one datasheet I looked at said that they were intended for use in low frequency RF amplifiers, not sure how low they were using them at, but I'd say they probably make a better audio tube than RF. I'm pretty sure that a GU13 is a Russian 813, and the GK71 is just a GU13 with a suppressor grid instead of the beam plates, making it a true pentode, where the GU13 is a beam power tetrode, just like the 813. I'll have to look, but the GK71 might be close to being equivalent to an 803, since they are basically a pentode version of the 813.

[kb3ouk]

GK71 and the 803 do seem to be pretty close electrically. Also, does anyone know where to find good, detailed datasheets for Russian tubes, maybe that give some operating parameters, kinda like the RCA datasheets and others?

[K6IC]

This GK-71 DS may not be as detailed as desired,  but ...:
http://frank.pocnet.net/sheets/018/g/GK71.pdf

GU-13:
http://frank.pocnet.net/sheets/018/g/GK71.pdf

Of course,  these are Frank's Tube Data Site,  probably most here know, but,:
http://frank.pocnet.net/

Just a quick search,  there is probably more detailed data elsewhere,  GL  Vic

[kb3ouk]

Yeah, those sheets are the ones I already looked at. There probably are some really detailed sheets out there somewhere, in Russian.

[kb3ouk]

Here's the most information I've been able to find on the GK71.
http://timelesson.blogspot.com/2009/12/gk-71-power-pentode.html