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radiocom
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Post subject: Are there any RF tube amp experts out there? Posted: Oct Fri 04, 2019 5:25 pm |
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Joined: Jul Tue 29, 2014 12:25 am Posts: 237 Location: Las Vegas, Nevada
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Can anyone tell me in simple terms the path of a signal thru a 1x3 tube amp. The mic is keyed and comes into the amp then where does it go. Does it go to the transistor that engages the relays or does it go to the driving 6LF6 tube that then sends voltage to the output tubes which then engages the relay? I'm trying to track down why the relays are not engaging but if I manually push the lower relay closed, the amp works and has output. I'm not getting voltage from somewhere to engage the relays. Attachment:
relay resize.jpg [ 322.3 KiB | Viewed 2836 times ]
Attachment:
20190921_062607-800x450.jpg [ 330.52 KiB | Viewed 2831 times ]
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Ylli
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Post subject: Re: Are there any RF tube amp experts out there? Posted: Oct Fri 04, 2019 6:07 pm |
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Joined: Aug Sat 17, 2019 8:55 pm Posts: 81
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Input is a mic with push-to-talk? Usually, the push to talk is simply a push button switch that completes the circuit to energize the relay. It could be directly or it could be through a 'buffer' of some kind. Would need to see more of the circuit to make any more detailed suggestions.
What has this got to do with RF?
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radiocom
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Post subject: Re: Are there any RF tube amp experts out there? Posted: Oct Fri 04, 2019 6:12 pm |
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Joined: Jul Tue 29, 2014 12:25 am Posts: 237 Location: Las Vegas, Nevada
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It's an RF amplifier
Let's ignore the pictures and tell me simply how does the signal travel through a simple 1 transistor with 1 driving tube and 3 output tube?
Thanks
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reeves03
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Post subject: Re: Are there any RF tube amp experts out there? Posted: Oct Fri 04, 2019 9:26 pm |
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Joined: Jun Sat 18, 2011 3:36 am Posts: 2415 Location: Milton, FL 32570
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radiocom wrote: It's an RF amplifier
Let's ignore the pictures and tell me simply how does the signal travel through a simple 1 transistor with 1 driving tube and 3 output tube?
Thanks Provide a schematic an I'm sure some can help you. Help us help you.
_________________ Thanks, Jason N1EBC
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radiocom
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Post subject: Re: Are there any RF tube amp experts out there? Posted: Oct Fri 04, 2019 9:36 pm |
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Joined: Jul Tue 29, 2014 12:25 am Posts: 237 Location: Las Vegas, Nevada
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Thanks for the reply but this one is homebrew and no schematic was ever drawn.
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Ylli
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Post subject: Re: Are there any RF tube amp experts out there? Posted: Oct Fri 04, 2019 9:55 pm |
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Joined: Aug Sat 17, 2019 8:55 pm Posts: 81
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Most likely, the input is applied to the control grid of the driver tube. Output taken from the plate. The outputs could be either common cathode with the signal applied to the control grid, or grounded grid with the input signal applied to the cathodes. In either case, the output comes from the plates into an impedance matching network (often a pi network) and feeds the antenna port.
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radiocom
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Post subject: Re: Are there any RF tube amp experts out there? Posted: Oct Fri 04, 2019 10:32 pm |
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Joined: Jul Tue 29, 2014 12:25 am Posts: 237 Location: Las Vegas, Nevada
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Thanks Ylli.
do you know where the transistor comes in to play?
Is it during input or output?
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Peter Bertini
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Post subject: Re: Are there any RF tube amp experts out there? Posted: Oct Fri 04, 2019 10:35 pm |
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Joined: Jan Thu 01, 1970 1:00 am Posts: 22193 Location: Somers, CT
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It appears to use RF sensing on the input to key the change over relays. I think I see a detector diode near the so-239.
_________________ Just because it can be done doesn't mean it should be done.
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radiocom
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Post subject: Re: Are there any RF tube amp experts out there? Posted: Oct Fri 04, 2019 10:40 pm |
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Joined: Jul Tue 29, 2014 12:25 am Posts: 237 Location: Las Vegas, Nevada
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Peter .... can you describe it to me?
is it the clear what I thought were transistors?
Thanks
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devilsmist
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Post subject: Re: Are there any RF tube amp experts out there? Posted: Oct Fri 04, 2019 10:44 pm |
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Joined: Jun Sat 15, 2019 7:43 pm Posts: 1108
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A linear with a driver tube is usually designed for illegal CB use. Do you have a ham license?
DM
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radiocom
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Post subject: Re: Are there any RF tube amp experts out there? Posted: Oct Fri 04, 2019 10:49 pm |
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Joined: Jul Tue 29, 2014 12:25 am Posts: 237 Location: Las Vegas, Nevada
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Of course and none of your business !!!
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reeves03
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Post subject: Re: Are there any RF tube amp experts out there? Posted: Oct Fri 04, 2019 11:11 pm |
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Joined: Jun Sat 18, 2011 3:36 am Posts: 2415 Location: Milton, FL 32570
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radiocom wrote: Of course and none of your business !!! A little snippy aren't since YOU are asking for help. How about trying to sketch out a rough schematic it will only help your learning.
_________________ Thanks, Jason N1EBC
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radiocom
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Post subject: Re: Are there any RF tube amp experts out there? Posted: Oct Fri 04, 2019 11:15 pm |
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Joined: Jul Tue 29, 2014 12:25 am Posts: 237 Location: Las Vegas, Nevada
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I apologize because I meant it jokingly and after i read it , it does sound rude. Sorry
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Macrohenry
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Post subject: Re: Are there any RF tube amp experts out there? Posted: Oct Sat 05, 2019 12:06 am |
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Joined: Jan Thu 01, 1970 1:00 am Posts: 4306
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radiocom
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Post subject: Re: Are there any RF tube amp experts out there? Posted: Oct Sat 05, 2019 12:42 am |
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Joined: Jul Tue 29, 2014 12:25 am Posts: 237 Location: Las Vegas, Nevada
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Macrohenry .... thank you. I did replace the transistor but no data sheet is available for a 2n600 to know which is emitter, base and collector so I tied it in the same as the old one. I'm thinking the collector should go to ground. I'm not sure
I am studying the schematic and will be back to you shortly or tomorrow because I have some errands to run.
I started this new thread because I was asking a different question.
Thank you
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reeves03
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Post subject: Re: Are there any RF tube amp experts out there? Posted: Oct Sat 05, 2019 2:48 am |
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Joined: Jun Sat 18, 2011 3:36 am Posts: 2415 Location: Milton, FL 32570
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_________________ Thanks, Jason N1EBC
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westcoastjohn
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Post subject: Re: Are there any RF tube amp experts out there? Posted: Oct Sat 05, 2019 9:18 pm |
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Joined: Dec Sat 24, 2011 9:17 pm Posts: 7148 Location: Vancouver Island, Canada
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Remember this for next time - to ask a new question about the same unit, go back to you very 1st post, Edit, then change the title of the post. These experts are smart enough to go to the last post, where they find the latest info. All one thread keeps the history of the unit before the new question without searching for it or having to ask for details. #2, If you make a 'possibly snarky' response, be polite, and say it with a smile. 
_________________ Watch the doughnut, not the hole. Burl Ives, RIP, oldtimer. [:l>)
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radiocom
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Post subject: Re: Are there any RF tube amp experts out there? Posted: Oct Sat 05, 2019 10:50 pm |
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Joined: Jul Tue 29, 2014 12:25 am Posts: 237 Location: Las Vegas, Nevada
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Thanks WestCoast for the advice. I Will heed that.
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radiocom
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Post subject: Re: Are there any RF tube amp experts out there? Posted: Oct Sun 06, 2019 11:39 am |
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Joined: Jul Tue 29, 2014 12:25 am Posts: 237 Location: Las Vegas, Nevada
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The 2n600 is a pnp ger from what I could find. 2n600 looks like a bolt.
Machenry.... the schematic is similar but more components than what I'm trying to repair so I'm having difficulty trying to follow the path.
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reeves03
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Post subject: Re: Are there any RF tube amp experts out there? Posted: Oct Sun 06, 2019 2:05 pm |
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Joined: Jun Sat 18, 2011 3:36 am Posts: 2415 Location: Milton, FL 32570
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