My newest selfmade linear with one GS35B

In March 2013 I start to build a big linear with linear with the Russian GS35B triode tube.  I was finish in December 2013. I like to show you here the steps from this project.

I got the tube from cheap eBay. Nobody liked to buy this tube because the cooler was a little bit deformed. I repaired the cooler and clean the tube. Under the dirt was a brand new tube 🙂

I collect the parts for this linear over one year on flee-markets.

The case will be a 19 inch 6 inch high server case. I will modify it.

I take all the stuff out and i made some new sheets for the holes.

The front is a 2 mm thick aluminium sheet.

I made a double bottom sheet, so the cables can be under the bottom. I start with the tube socket. A fried of me, DF2PY, made me this socket. I coat it with silver.

That was the first time I tried the tube in the socket.

The finish socket with the input circuit from under side.

From upper side it looks like this. The air can flow trough the socket.

Over the tube comes a chimney.

Under the socket is the air flow sheet. All the air must trough the tube socket.

This are the power supple circuit boards. I made all by my self.

This is the self made adapter for the big load capacitor.

Here he is build in, with the adapter.

The UHF trap for the tube. The resistor and the cooper is very solid 🙂

The first version of the anode coil, everything is self made. This is POM plastic.

The vacuum relays for the transmit/receive switching

The plate side of the PI-Filter

A overview of the work, so far

Now is everything finish inside.

The underside is finish too. The Soft start with overheat control is from China. The Rest of the PCBs is self made. The voltages are 3800V DC, 24V DC, 12.6V AC.

The anode voltage is near 4000 volts!

The first test front look like this

This is the finish linear. Its stable like a tank 🙂

The Output (PEP) of this linear with only 85W(10m) 100W(80m) input from my IC-746:

80m 1600W
40m 1500W
30m 1500W
20m 1500W
17m 1500W
15m 1500W
12m 1400W
10m 1200W
06m 0650W (But its only 25W allowed in Germany on 6m! So I test it only on a dummy)
With my FT-277 and the 150W input the linear makes 2000W Output 🙂
In Germany is only 750W PEP allowed on shortwave. So the Linear works with under 50% and stay quit cool and make a clean signal 🙂

Here you can download the schematics for the RF Part: HF_Teil

Here you can download the schematics for the power supply (Diodes): Netzteil_Dioden

Here you can download the schematics for the power supply (capacitors): Netzteil_Plan

bias board W4ZT
The schematics for the bias control

I still have this linear and I don’t like to sell it. It works so great.

7 thoughts on “My newest selfmade linear with one GS35B

  1. Very nice!
    Do you have schematic, parts list, and further construction details available?
    Henry Copeland

  2. I used GS35 few decades ago,mainly in BC applications.High voltage used here is too high,GS35 should not be operated with more 2500V if you wish long life tube.For example,with 2000V of Ua,as broadcast transmitter,in non-stop service ,GS35 survive for tree years with 1KW OUT,and after that power drops 800W.With 800W tube works 6-8 months and then died completely.With 3000V Ua,under same conditions,tube survive less than year…I do not like ceramic tubes for HAM PA because they are too noisy so I do not have experience with GS35 on HF!

    • Hi YU1SU,
      you are right. But when you have a hand selected tube, not the cheap stuff in ebay, you can easy use a much higher Ua. I use my constallation now so many years with no problems. The maximum temp, are 38 celsius after a contest over 3 days with 1 KW out. And when the tune broke after some years, I have a other one 🙂 lol

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