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References: [ +subject:/^(?:^\s*(re|sv|fwd|fw)[\[\]\d]*[:>-]+\s*)*\[Amps\]\s+Initial\s+test\s+of\s+813\s+amplifier\s*$/: 11 ]

Total 11 documents matching your query.

1. [Amps] Initial test of 813 amplifier (score: 1)
Author: Vic K2VCO <vic@rakefet.com>
Date: Sun, 15 Aug 2010 00:04:22 -0700
I did some testing of my 2 x 813, class-c grid-driven amplifier under HV for the first time today. After adjusting the neutralization (with HV off), I applied HV and set the bias for 50 ma ZSAC (ther
/archives//html/Amps/2010-08/msg00210.html (7,479 bytes)

2. Re: [Amps] Initial test of 813 amplifier (score: 1)
Author: "Bill, W6WRT" <dezrat1242@yahoo.com>
Date: Sun, 15 Aug 2010 04:53:26 -0700
ORIGINAL MESSAGE: REPLY: The amp should be stable with or without a load (both input and output), but the shields should be in place too. Try it again when they are. Is there a VHF parasitic suppress
/archives//html/Amps/2010-08/msg00212.html (7,221 bytes)

3. Re: [Amps] Initial test of 813 amplifier (score: 1)
Author: "Carl" <km1h@jeremy.mv.com>
Date: Sun, 15 Aug 2010 08:34:11 -0400
I think you answered your own question Vic. Once that is done touch up the neutralization and then see if it holds at power. Even some older commercial amps are marginally stable which is why they us
/archives//html/Amps/2010-08/msg00213.html (9,010 bytes)

4. Re: [Amps] Initial test of 813 amplifier (score: 1)
Author: Rick Stealey <rstealey@hotmail.com>
Date: Sun, 15 Aug 2010 13:01:51 +0000
Vic, I think if it is an HF oscillation the plate tank components will have a large effect on it, whereas if it is a parasitic they won't. In fact, if it is an HF osc you can probably stop it entirel
/archives//html/Amps/2010-08/msg00215.html (7,316 bytes)

5. Re: [Amps] Initial test of 813 amplifier (score: 1)
Author: "Fuqua, Bill L" <wlfuqu00@uky.edu>
Date: Sun, 15 Aug 2010 09:43:15 -0400
With out some load the voltage gain of the amplifier will be very high. Also, if no signal has been applied the tuning positions of both the input and output capactiors may be abount anywhere on any
/archives//html/Amps/2010-08/msg00216.html (10,816 bytes)

6. Re: [Amps] Initial test of 813 amplifier (score: 1)
Author: "Fuqua, Bill L" <wlfuqu00@uky.edu>
Date: Sun, 15 Aug 2010 10:08:30 -0400
One other thing. It is always a good idea to very high negative bias on the tubes when not transmitting. One is to prevent the possibility of an oscillation the other is less obvious. If you are usin
/archives//html/Amps/2010-08/msg00217.html (12,902 bytes)

7. Re: [Amps] Initial test of 813 amplifier (score: 1)
Author: Vic K2VCO <vic@rakefet.com>
Date: Sun, 15 Aug 2010 07:34:36 -0700
Yes, there are VHF suppressors. I am thinking that the neutralization was upset because I adjusted it before I installed the plate transformer, which is not that far from the neutralizing capacitor.
/archives//html/Amps/2010-08/msg00218.html (9,121 bytes)

8. Re: [Amps] Initial test of 813 amplifier (score: 1)
Author: Vic K2VCO <vic@rakefet.com>
Date: Sun, 15 Aug 2010 07:53:41 -0700
That's what I observe. As several others said, there are plenty of feedback paths, especially without the shielding. When I adjusted the neutralization I got a significant dip in RF feedthrough, but
/archives//html/Amps/2010-08/msg00219.html (8,325 bytes)

9. Re: [Amps] Initial test of 813 amplifier (score: 1)
Author: Vic K2VCO <vic@rakefet.com>
Date: Sun, 15 Aug 2010 08:23:03 -0700
My t/r circuit applies bias beyond cutoff when the ptt is open. When it's closed, the bias drops to a point which allows 50 ma of zero-signal plate current (about -50V). When drive is applied, rectif
/archives//html/Amps/2010-08/msg00220.html (10,263 bytes)

10. Re: [Amps] Initial test of 813 amplifier (score: 1)
Author: "Carl" <km1h@jeremy.mv.com>
Date: Sun, 15 Aug 2010 12:43:45 -0400
A low value carbon resistor right at the grid pin may be enough to finish the taming once youve completed the rest of the work. Ive used 10-33 Ohms in several tetrode rigs and amps that were otherwis
/archives//html/Amps/2010-08/msg00222.html (12,243 bytes)

11. Re: [Amps] Initial test of 813 amplifier (score: 1)
Author: Vic K2VCO <vic@rakefet.com>
Date: Sun, 15 Aug 2010 09:57:06 -0700
Sounds good, and I'll do that. Can't possibly hurt. -- Vic, K2VCO Fresno CA http://www.qsl.net/k2vco/ _______________________________________________ Amps mailing list Amps@contesting.com http://list
/archives//html/Amps/2010-08/msg00227.html (8,990 bytes)

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