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Total 418 documents matching your query.

381. [Amps] Sanity check (score: 1)
Author: Vic K2VCO <vic@rakefet.com>
Date: Fri, 03 Dec 2010 14:54:50 -0800
I am doing something dumb, but I can't figure out what. My new amp is a pair of 813's, class C. On 20 meters, it loads to 500 ma at 2050 volts and produces about 800 watts output. The tuning capacito
/archives//html/Amps/2010-12/msg00019.html (8,024 bytes)

382. Re: [Amps] Sanity check (score: 1)
Author: Vic K2VCO <vic@rakefet.com>
Date: Fri, 03 Dec 2010 18:06:52 -0800
I am using a 1kw Bird element. So that might be the explanation for the slight drop in power. I have a VFD digital power meter that I can try. -- Vic, K2VCO Fresno CA http://www.qsl.net/k2vco/ ______
/archives//html/Amps/2010-12/msg00022.html (10,432 bytes)

383. Re: [Amps] Sanity check (score: 1)
Author: Vic K2VCO <vic@rakefet.com>
Date: Fri, 03 Dec 2010 19:32:03 -0800
I am not sure that it works properly when the coaxial part of the tank coil is tapped. WC6W has experience with this and it's possible that he only used it in the highest frequency section of the tan
/archives//html/Amps/2010-12/msg00023.html (10,946 bytes)

384. Re: [Amps] PI-L Thoughts! (score: 1)
Author: Vic K2VCO <vic@rakefet.com>
Date: Sat, 11 Dec 2010 11:04:51 -0800
There's one more possibility that you haven't mentioned: add a small inductance between the plate and the input of the pi-network. This makes it an "L-Pi" or "L-Pi-L" network. The effect is to transf
/archives//html/Amps/2010-12/msg00108.html (10,500 bytes)

385. [Amps] Drive requirements (score: 1)
Author: Vic K2VCO <vic@rakefet.com>
Date: Sat, 11 Dec 2010 16:43:34 -0800
I am happy to say that I am getting 800 watts out on all bands except 10 m from my grid driven class C 2x813 amp at about 1 kw input. I still have to make adjustments to the 10m plate circuit. Now, h
/archives//html/Amps/2010-12/msg00122.html (7,335 bytes)

386. [Amps] Don't do this (score: 1)
Author: Vic K2VCO <vic@rakefet.com>
Date: Sat, 18 Dec 2010 14:26:29 -0800
Having finally finished my 813 amp and put it into service, I took my SB-1000 to the bench to find out what had caused the loud ZZZZAAAP and blew the fuses last week. I found that one of my clever mo
/archives//html/Amps/2010-12/msg00213.html (7,257 bytes)

387. Re: [Amps] Fuses (score: 1)
Author: "Vic, K2VCO" <vic@rakefet.com>
Date: Thu, 06 Jan 2011 20:14:54 -0800
You can also get some values of 250v ceramic fuses at Home Depot, etc. They are used in microwave ovens. I agree that slow blows are not likely to be correct for an amplifier -- they are very slow an
/archives//html/Amps/2011-01/msg00051.html (8,780 bytes)

388. Re: [Amps] Fuses (score: 1)
Author: "Vic, K2VCO" <vic@rakefet.com>
Date: Sat, 08 Jan 2011 01:44:58 -0800
Which is one reason the fuse should be a fast-blow type -- to save the surge resistor in the event of a flashover. -- Vic, K2VCO Fresno CA http://www.qsl.net/k2vco/ __________________________________
/archives//html/Amps/2011-01/msg00080.html (7,981 bytes)

389. Re: [Amps] DX-60 (score: 1)
Author: Vic K2VCO <vic@rakefet.com>
Date: Mon, 17 Jan 2011 09:10:07 -0800
I had a DX-60 some years ago, and it used a form of grid-block keying for CW. Here's a schematic of it: <http://members.cox.net/n4jk/images/dx60b1.jpg> Sorry I don't know why it blows the modulator t
/archives//html/Amps/2011-01/msg00174.html (8,988 bytes)

390. Re: [Amps] Fireing up a old Tl922 amplifier. (score: 1)
Author: Vic Rosenthal <vic@rakefet.com>
Date: Fri, 21 Jan 2011 07:40:27 -0800
I don't think you need anywhere near as much delay either for the filament or the plate of 3-500Z's. All you need to do for the filament is limit the inrush current while it's cold. A half-second sho
/archives//html/Amps/2011-01/msg00213.html (14,018 bytes)

391. Re: [Amps] AL-811 & 572's (score: 1)
Author: Vic K2VCO <vic@rakefet.com>
Date: Fri, 21 Jan 2011 10:47:20 -0800
150 ma. on the grid and 400 ma on the plate (due to power supply limitations). The 572B's absolute maximum rating is 275 ma per tube, but at the low plate voltage in that amp it probably isn't possib
/archives//html/Amps/2011-01/msg00217.html (8,839 bytes)

392. Re: [Amps] Help with HL2200 6 meter conversion (score: 1)
Author: Vic K2VCO <vic@rakefet.com>
Date: Sat, 22 Jan 2011 03:21:07 -0800
First of all, you can't trust the dip meter because the frequency will change when you couple it to the tank circuit. When I use one I wrap a turn or two of wire around it and connect it to a frequen
/archives//html/Amps/2011-01/msg00224.html (12,295 bytes)

393. Re: [Amps] Pi/L in Ameriton amps? (score: 1)
Author: Vic K2VCO <vic@rakefet.com>
Date: Wed, 26 Jan 2011 07:06:30 -0800
It's common to use a pi-L only on the lower bands and a simple pi on the higher ones. This may be in order to use a smaller-sized output capacitor. Or perhaps additional harmonic suppression is neces
/archives//html/Amps/2011-01/msg00309.html (9,770 bytes)

394. Re: [Amps] 811A vs 572B (score: 1)
Author: Vic K2VCO <vic@rakefet.com>
Date: Mon, 14 Feb 2011 12:40:52 -0800
How do you know it was a VHF parasitic? What were the circumstances of the event? -- Vic, K2VCO Fresno CA http://www.qsl.net/k2vco/ _______________________________________________ Amps mailing list A
/archives//html/Amps/2011-02/msg00107.html (7,523 bytes)

395. Re: [Amps] Al-82 Blowing fuses? (score: 1)
Author: Vic K2VCO <vic@rakefet.com>
Date: Mon, 28 Feb 2011 14:19:12 -0800
I understand that slow-blow fuses are intended for motors and similar devices that normally take a longish time -- maybe a few seconds -- to come up to speed and draw much more current in that period
/archives//html/Amps/2011-03/msg00001.html (9,172 bytes)

396. [Amps] Wanted: chart frame (score: 1)
Author: Vic K2VCO <vic@rakefet.com>
Date: Mon, 21 Mar 2011 11:30:46 -0700
Does anyone have one of those chart frames, found (for example) on BC-375 tuning units, that they are willing to part with? -- Vic, K2VCO Fresno CA http://www.qsl.net/k2vco/ _________________________
/archives//html/Amps/2011-03/msg00154.html (6,769 bytes)

397. Re: [Amps] SB 200 blown diodes in power supply (score: 1)
Author: Vic K2VCO <vic@rakefet.com>
Date: Thu, 24 Mar 2011 11:20:38 -0700
Replacing just one diode is asking for trouble. Unmatched diodes are much more likely to blow. I suggest that you order 1N5408 diodes online (you won't find them at Radio Shack). You can get them for
/archives//html/Amps/2011-03/msg00191.html (9,359 bytes)

398. Re: [Amps] SB-200 power supply diodes (score: 1)
Author: Vic K2VCO <vic@rakefet.com>
Date: Sat, 26 Mar 2011 07:49:14 -0700
I agree. I didn't think about the holes when I recommended the 1n5408's. They have a higher current rating, of course, but as Jim says, it won't make any difference in the SB200. -- Vic, K2VCO Fresno
/archives//html/Amps/2011-03/msg00204.html (9,269 bytes)

399. Re: [Amps] Homebrew is back.. (score: 1)
Author: Vic K2VCO <vic@rakefet.com>
Date: Tue, 29 Mar 2011 09:52:55 -0700
I am presently running one graphite-plate (WWII vintage) 813 and one metal-plate RCA 813 in my class-C amplifier. I'm running them at about 2050v and 500 ma in CW service, and I haven't noticed any c
/archives//html/Amps/2011-03/msg00256.html (10,476 bytes)

400. Re: [Amps] 813 Amplifier Article (score: 1)
Author: Vic K2VCO <vic@rakefet.com>
Date: Wed, 30 Mar 2011 16:33:57 -0700
Looks good to me. If you have more tubes than you need, I'm accumulating NOS ones to build yet another 813 amplifier. I would like to build one with 4 of them this time! -- Vic, K2VCO Fresno CA http:
/archives//html/Amps/2011-03/msg00276.html (7,705 bytes)

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