GS-35b

[KC2IFR]

Im working on an amp conversion to a GS35b toob. Anyone out there have experience with this toob?????

Thanks,
Bill

[W5GA]

Our friend down under has built several.
See here...http://forums.hamisland.net/showthre...689-Amplifiers

[VK3ZL]

Extremely rugged tube Bill..What amp are you considering for the conversion?? The 35B operates best with 3.5-4kv HT...Needs plenty of air through the cooler...I have never used parasitic suppressors on any of the Russian triodes on HF-6 meters....Totally docile and well behaved....Set up Pi input networks drive resistance around 50ohms...I use fixed C, C1 and 2 and slug tuned inductors on cathode inputs..For general SSB use, idle tube around 130-150ma...When both input and output networks are correctly tuned you will find the tube easily has the 13db and slightly higher gain...If your cooling and HT power supply are adequate you can easily drive the tube well beyond the 1500 watt power limit...Grid current when properly loaded will be about 1/3 anode current...Some of the more daring don't bother monitoring grid current, however I use that as an indication of proper loading..You don't need a fancy tube socket, just mount the tube by clamping the grid ring direct to the chassis with a couple of shaped washers...The filament and cathode connections can be done using some copper strap..

I have build about seven GS-35B and 31B amplifiers these past couple of years and all are excellent performers....

Bob..VK3ZL..

[KC2IFR]

Hi Bob.....A while back I bought a home brew amp running 2 4-400's. As it turned out, the amp was never on the air because of problems with the screen supply and the builder died before he could fix it. The amp is extremely well built with a large power supply that will supply at least 4KV at 1.5 amps or more. It uses a B&W 850a tank ckt and a tuned input ckt. I decided to go with some sort of grounded grid triodes or triode. My first choice was a pair of 3-500zg's but a friend of mind who is helping me with the project, talked me into the GS-35b. He helped another ham build this.....https://home.comcast.net/~w1ia/new_page_7.htm.......I have pics of my amp that I will post soon.......I have to reduce the file size!!!!!!

Bill

[KC2IFR]

Pics of the 4-400 amp...
4400front.jpg4400powersupply.jpg4400rear.jpg

[KC2IFR]

By the way Bob.........saw pics of your work. U are a true artist when it comes to home brew equipment.
I also have health problems......had a bad heart attack and my back is a mess. I hope your feeling better and can continue with your outstanding projects.

more to come.....

Bill
KC2IFR

[VK3ZL]

Hi Bill, that's one serious looking piece of amplifier..Way past what I could manage to build..It should be fun converting it over to a 35B...We have to put up with our life and whatever problems we face, health etc...I am champing at the bit at the moment wanting to get back to work...

Let me know how you progress with that amplifier..It looks as though the work would be minimal...Looks like a big Dahl Ht transformer in the cabinet...I have one of those in my water cooled 160 meter amplifier...Horsepower to spare..

Bob..VK3ZL..

[KA9MOT]

Man, that thing is amazing..........

[kf0rt]

Hey Bill -- used to see a fair amount of that kind of construction in the 70's. Homebrew all the way and in rack systems. Some were 6' racks, but some were smaller. 4-1000's, 3-500's and 4-400's were popular.

Got a question, though. What's that deck in the middle? I'm used to seeing a configuration with the PS in the bottom and a single RF deck. Is that a modulator? Doesn't seem to be wired for RF or as a serious power component.

Way cool amp, tho... Brings back some memories.