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Fast Carrier Tuning the 811H Amplifier
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- čas přidán 31. 12. 2023
- The single most important thing to watch when tuning a grounded-grid AB2 linear amplifier is grid current. Be wary of instructions or videos telling you to "dip the plate".
"Dipping the plate" came from years ago when stages were grid-driven and the only output metering was plate current. As a matter of fact, until 1983 Spring the FCC required Hams to know the plate power input. This required we watch the plate current constantly.
Also, grid-driven stages cannot be loaded and tuned by watching the control grid current. Grid-driven tetrodes or pentodes can be tuned by watching the screen grid current, but almost no Ham equipment manufacturer provided screen current meters.
As a consequence, Hams were conditioned, trained, or predisposed to tune by "dipping the plate". Old habits being hard to break, older Elmers passed on "dipping the plate" to generations beyond the grid-driven stage era. I'm not saying plate current is not valid for many things, but this video shows how much faster tuning can be by watching grid current in AB2 grounded-grid amplifiers. Faster tuning means less wear and tear, and less interference.
I still think the best way is to use a TOF and a tuning pulser to set the grid current.
This video shows the fastest way to tune with a carrier!
Thank you for clearing up so much of my confusion with tuning my LA! I was intimidated by it and always worried about damaging the tubes. Your clear explanation has saved me a lot of worry!
Honestly, I went from not having a clue on how to set up a tube amplifier to completely understanding from this video. Amazing presentation and perfect layman explanation, thank you.
I have had my 811H for over a year now and I find that the initial dial settings in the instructions are right on. This is a big help in keeping the tubes etc good.
The mystery just vaporized.
I have an 811 on order now.
Thams again.
Thanks Tom, this was so much help. I have the SB-221 with the grids at ground. I've been working way to hard turning it. Your method really puts it into simple talk. W4FLI
My Elmer had one of those classic Heathkit SB-221 amps and it was an absolute pile up breaker ..
Can’t be better explanation 👍 thank you very much Sir and happy new year
Hope you have a great New Year Tom, Larry, KB9IKY! Loving my AL-80B sense you worked your magic on it.
Thanks Larry! Happy New Year!
Thx Tom.. Big fan of all of your stuff on CTR Engineering inc too. A must read for any 811 0r 811H owners. I have all the upgrades from CTR ready to order soon as Birthday present, however- I have been using my AL-811H for 5 years now with no issues- same tubes even. Maybe I just got lucky with my tubes since it seems i haven't been using enough exciter power for the tune up. I did install the GOP-100 to protect accidental overdrive though. I have been tuning it with a 50 watt cw carrier and on SSB the exciter sits at 30-40 watts- usually runs about 300-400 peak with a low SWR and just have fun with it.. 73s and thx for another great vid. W5YAK
Was a big help & I’ve been doing this over 30 years. Much easier.
Happy New Year Tom!
Happy New Year!
Will 5 watts output (lowest setting I can get) cause the grid current meter to move during this test?
I have been afraid of a tube amp due to this issue with the tuning. But at the price point per watt it makes sense to get the tube type. A solid state is ok but then they get you with the power supply and screw that. Not paying another grand for a power supply. Thanks for the good info
Tom, what would prevent me from getting Grid current above 40mA on my 20Meter range please? My 40m will get >150ma Grid & >450plate? Thanks great video. So many other videos talk of peaking plate & not grid. Any help would be greatly appreciated
Very very helpful video. Thanks Tom.
Thanks Tom. Is tuning a Tetrode tube amplifier done the same way?
Very informative video. Do these grid current readings also apply to the 572Bs in an AL-811HD?
I don't know about that, seems like many people need several hours to peak and tune their amps, especially when the net starts!
LOLOLOL!!! Right!! "The Tuneuppers" Kill me when they do it dead on frequency too. It's like "dude- just move off frequency a tidbit when you are doing that" W5YAK
@@markyakubovsky3380 It's better when they also mess with the VFO and 'wiggle the knob' for that siren effect as well!
I wonder how often their coax has to be replaced tho. Seems like anyone in their neighborhood isn't going to ignore the behavior for long.
Could you do the same thing but instead of a power meter following the amplifier could you have a tuner as the tuner has also essentially a watt meter there showing both the forward and reverse power. Because of course the tuner is President normally I have the tuner when I'm setting the amplifier in coax bypass when I'm doing the tuning of the amplifier
Excellent info. What would be the best grid current for a three tube 811 amp?
Great information! Thanks!
Tom, I just want to thank you for this video! Dang, the manuals and other well-intentioned hams would have new-to-amp folks like me thinking that proper turning is some kind of esoteric activity. You have simplified it quite a bit.
Question: I have an 811H that I picked up used and will be installing a new set of 572B tubes. What mA value am I shooting for with the 572's?
Thanks for your videos. They are very helpful. Sub'd.
What is the grid current for an AL-80B tuning this way with 100W drive power? In another video you take it up to 200mA but that amp had a TOF.
Hello, Can the tuning method be applied to a Ranger 811H amplifier ? The schematics are similar.
Finally, the BEST video! How to properly tune an Ameritron AMP. Happy New Year 2024 de KF5YUB
Can you explain tuning an AL80B with a carrier and no TOF? I’m sure the process is the same but what should the grid current be for the single 3-500z?
Once the amp is tuned using this method, can the output of the radio be lowered to give the desired output from the amp?
I am on your site constantly reading. When are you going to write a book! I'd buy it. W6ORV / AL-811 Power Supply Kit / Fan Kit / P Suppressor Kit / 2022 build so it came with the 811R200K configuration.
How do you trigher the amplifier with no Drive. There is a relay connection between the radio and the amplifier and when you either hit the key or the press the microphone there's going to be some level of Drive even if it's low. My ts2000 gets 5 watts. How am I going to do that with zero power unless of course I disconnect the output power of the radio into a dummy load and just simply have the key operate the relay
There is always a way to do this. On SSB in a quiet room, or with the microphone and power turned way down. On CW with no key plugged in or no key closed, and you push the microphone PTT button, hit send, or whatever triggers the amp.
Or you can just short the amplifier Relay jack manually to test the diode.
@@Jerrythenerdful thank you
Thank you, Tom. K7KDX
If I follow the procedure in the video works flawlessly and I get the 800 watts (happy about that) but then when I’m reading the manual it says about never exceed 80 watts so that confuses me because I want to treat well the amp but with 80 watts I don’t get more than 550watts. So do I trust the manual that should be the gospel or this video?
So will this work on a Heathkit SB-200? Obviously the grid current will be lower
Excellent!!
Can you do a video on how to set up a d use a pulse tuner on the Azl811H?
One question I wish you could answer when I ordered this 811H I paid more for a grid protection circuit board. This seems to limit my input dirve power to just 50 watts key down. Any higher and the amp shuts off and I have to put the standby switch to standby and then that resets the amp. Is that how it is supposed to work? de WB7ORB
The GOP trips at a certain quasi-average current. I initially designed the GOP back around 1983 for the AL1500. How much current does it trip at? Have you tested that? I need more details to answer.