Another amplifier..

[VK3ZL]

Hi all..I havn't posted any amplifier pics for a long while so thought you may like this little 6 meter unit..I have built and sold about 10 of these around VK, US and South Africa over the past two years...

I design and build these here in my little cramped workshop and each new project gets some new additional upgrades on the last...This unit is designed around a pair of the Russian GI-6B pulse triodes...These tubes are very rugged and willing workers..Modest power output, 700 watts output with about 30 watts of drive..The circuitry is simple with no frills...The tubes only cost $50 a pair so that's a lot of bang for the bucks...I have all my HT and filament transformers custom made in China for a very reasonable rate and the quality is excellent with no failures..I only use new components..Each of these amplifiers costs about $600 in parts to build including the amplifier case which I construct by hand..I include a reliable step start for the HT and a variable bias circuit that can be set from the front panel..This unit was constructed for a VK6 about three months ago and he is very pleased with the job....That makes me feel good...It takes me about two weeks working a few hours each day from start to finish...The amplifier case is the hardest part as the metal work must be solid and accurate...I use my small lathe to machine a few of the components such as the tune disc capacitor and amplifier legs..I cool this simple amplifier with two 240 volt 4 inch muffin fans blowing air into the cathode compartment...The air then goes up through the tube cooler with Teflon chimneys and is evacuated with a good all metal Papst fan on the top cover....These amplifiers will run 300 watts of JT65, data modes all day barely warming up..Most of the VK hams use these amps for Meteor scatter.

I have also just completed a pair of 2 and 6 meter amplifiers for EME work...The 6 meter amplifier uses a GS-35B tube and the 2 meter unit a GS-31B tube..These units run 1kw ( GS-35B) and 600 watts (GS-31B) in data mode. The cooling is achieved using large internally mounted Papst 6 inch fans...These are rated at 285CFM in free air and easily deliver 140CFM through the tubes...I will post some pics of these two amplifiers in a later post..

This hobby has been a real pleasure to me especially in my older years..Each new project gives me a real buzz..

Enjoy the pics..

[PA5COR]

Beautifull made and looking, betting they will work very well for decades to come.

[kf0rt]

You are a true artist with that stuff, Bob. Well done!

[N2CHX]

Wow! I'm impressed. Beautiful work. Works of art, I'd call them.

[W3WN]

Bob,

Wow. (What else can one say?)

I wish I could afford your stuff!

[NQ6U]

Beautiful work, Bob. As usual, of course.

[K7SGJ]

Another fantastic job, Bob. I never get tired of looking at your work. Your metal work always amazes me. It's hard to believe you can turn a flat piece of metal into a work of art like that, all by hand. I'm still using sardine cans.

[w0aew]

I hate talent.

[K7SGJ]

Me too, unless it's my own. Not much chance of that happening, though.

[KA9MOT]

Damn... That thing is almost as sexy as Gretchen.....