I smiled when I saw your grid grounding system. The looping of a wire or wires from pin to pin & then grounding at one point, especially using #16 wire would not be found in the handbook of "Good Engineering Practice" ! Having three flat conductors in parallel materially reduce the inductance. I notice that there are those who claim insane power output from a pair of 3-500 tubes. My Eimac data sheet says 4000 volts DC on the anode & 400 mils of Ip constitute the absolute maximum limit for the tube. That figures to be 3200 watts input power. If you allow 65% SSB efficiency that calculates to 2080 watts output to the load. If the amp needs 100 watts of drive, then if the input power feedthrough would ideally be 100 % , then 2180 watts PEP would be maximum RF output. I dunno about these multi thousand watt outputs come from. In any case, I don't know what the saturation power output would be, but I expect that even with a very stiff power supply, saturation would occur without much more output. I stand to be corrected, because I an not an expert in these matters. Your grounding system is the same as I have done for years, & I was a bench tech for Heathkit in Canada 60 years ago. You have very good videos Sir. Cheers! Brian
Some people care more about money then honesty . Hams know better and don’t follow that nonsense As would eat through tubes and wipe out the entire band if they ran their pa like a cb person Always boils down to math , not rocket science . Some people are easy to fool. But like I said before , hams know better Thank you for the post Big surprise coming
Just wanted you to know I enjoy your content. Also.. thank you for showing people that dont know the correct way to ground the grids.. the “ other “ way makes me cringe.
We have done this to a 4-1000a amp that we are building. we soldered the straps directly to the socket then attached to the chassis. The straps we made are very short.
Good question thank you for asking A little bit of each. I am lucky to have some very incredibly smart friends in the field unfortunately some have since passed , who unloaded all they know on this stuff. They were fascinated that someone in their teens (when I first started) was into linear tube rf amps. I absorbed all that I was told. I also helped in an electronics shop. Read all sorts of books sone by William Orr and last countless hours of hands on experience. I continue to learn new tricks and other info. Can never learn enough. 73
A very nice way to ground the grids but why did they not do that in the beginning? no one has really explained that Heathkit had great Engineers how did they make that mistake
They made multiple mistakes all of which I correct. Info on why they didn’t ground the grids is available online. Reason for forced bias and no meter protection, can’t say. Modern pa’s don’t have these design flaws.
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I smiled when I saw your grid grounding system. The looping of a wire or wires from pin to pin & then grounding at one point, especially using #16 wire would not be found in the handbook of "Good Engineering Practice" ! Having three flat conductors in parallel materially reduce the inductance. I notice that there are those who claim insane power output from a pair of 3-500 tubes. My Eimac data sheet says 4000 volts DC on the anode & 400 mils of Ip constitute the absolute maximum limit for the tube. That figures to be 3200 watts input power. If you allow 65% SSB efficiency that calculates to 2080 watts output
to the load. If the amp needs 100 watts of drive, then if the input power feedthrough would ideally be 100 % , then
2180 watts PEP would be maximum RF output. I dunno about these multi thousand watt outputs come from. In any case, I don't know what the saturation power output would be, but I expect that even with a very stiff power supply, saturation would occur without much more output. I stand to be corrected, because I an not an expert in these matters. Your grounding system is the same as I have done for years, & I was a bench tech for Heathkit in Canada 60 years ago. You have very good videos Sir. Cheers! Brian
Some people care more about money then honesty . Hams know better and don’t follow that nonsense
As would eat through tubes and wipe out the entire band if they ran their pa like a cb person
Always boils down to math , not rocket science . Some people are easy to fool. But like I said before , hams know better
Thank you for the post
Big surprise coming
Just wanted you to know I enjoy your content. Also.. thank you for showing people that dont know the correct way to ground the grids.. the “ other “ way makes me cringe.
Thank you sam
I like the short and sweet videos. Also appreciate the clean language. Thanks for sharing your knowledge.
Your welcome , thanks for watching
We have done this to a 4-1000a amp that we are building. we soldered the straps directly to the socket then attached to the chassis. The straps we made are very short.
How did you learn to repair amps, formally trained, mentor, or self taught?
Good question thank you for asking
A little bit of each. I am lucky to have some very incredibly smart friends in the field unfortunately some have since passed , who unloaded all they know on this stuff. They were fascinated that someone in their teens (when I first started) was into linear tube rf amps.
I absorbed all that I was told. I also helped in an electronics shop. Read all sorts of books sone by William Orr and last countless hours of hands on experience.
I continue to learn new tricks and other info. Can never learn enough.
73
@amprepairguy Awesome! Unfortunately I don't have that luxury so guess I'll just have to continue reading and watching your videos. Thx!
Very welcome
A very nice way to ground the grids but why did they not do that in the beginning? no one has really explained that Heathkit had great Engineers how did they make that mistake
They made multiple mistakes all of which I correct. Info on why they didn’t ground the grids is available online. Reason for forced bias and no meter protection, can’t say. Modern pa’s don’t have these design flaws.
Enjoyed your video. I got rid of my SB-220 'cause of this problem. I now own an AL-82 amplifier which, in my view is a better amp
de W1VTP
gosh, no chicken band 5 kw test, no profanity ? what to do what to do ?