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281. [Amps] Alpha 8410 using 4CX1500B - why? (score: 1)
Author: John Lyles <jtml@losalamos.com>
Date: Fri, 31 Oct 2014 00:22:28 -0600
Don't be concerned over idling current in tetrodes. As long as you can cool the tube, let it conduct to whatever it takes for IMD. I've made amplifiers from ~3 to 200 MHz, for 30 years now, as work r
/archives//html/Amps/2014-10/msg00267.html (15,233 bytes)

282. [Amps] Harris RF103A amplifier (score: 1)
Author: John Lyles <jtml@losalamos.com>
Date: Sun, 23 Nov 2014 00:35:11 -0700
Commercial HD linear power amplifier, channelized tuning, 2-30 MHz. This is a late version. 1 kW out, < 100 watt input, single 3-1000A, power supplies built in. Not tested. This thing would be very e
/archives//html/Amps/2014-11/msg00040.html (6,622 bytes)

283. [Amps] Update on Tube Sources (score: 1)
Author: John Lyles <jtml@losalamos.com>
Date: Thu, 27 Nov 2014 23:07:17 -0700
The info below was pulled from the Oct. 2, 2004 Archives of this list. Here is a 10 year later update to this: 1) Amperex/Covimag plant in France has ceased making tubes, including glass 4-400, 3-500
/archives//html/Amps/2014-11/msg00060.html (11,056 bytes)

284. [Amps] Input VSWR of common grid amplifiers (score: 1)
Author: John Lyles <jtml@losalamos.com>
Date: Tue, 13 Jan 2015 23:08:52 -0700
In 2009-2012 I completed the design and testing of a very large tetrode amplifier that ran in grounded grid configuration. Grids not tied directly to ground, but grounded for RF via cavity circuits t
/archives//html/Amps/2015-01/msg00105.html (9,648 bytes)

285. [Amps] Input VSWR of common grid amplifier (score: 1)
Author: jtml@losalamos.com
Date: Tue, 13 Jan 2015 14:12:22 -0700
In 2009-2012 I designed some very large tetrode amplifiers that used grounded grid configuration. Not tied directly to ground, but grounded for RF via cavity circuits that have built in blocking capa
/archives//html/Amps/2015-01/msg00137.html (9,431 bytes)

286. [Amps] 5 Minutes for Ameritron 811H to warm up? (score: 1)
Author: John Lyles <jtml@losalamos.com>
Date: Sun, 25 Jan 2015 22:21:54 -0700
Ceramic/metal construction is usually very vacuum tight, with exceptions due to mfr mistakes. Somewhere I have a paper from Eitel-McCoulough extolling the virtues of their new "CX" tubes back then. G
/archives//html/Amps/2015-01/msg00288.html (9,866 bytes)

287. [Amps] {Collins} Understanding Screen Current in a Tetrode (score: 1)
Author: John Lyles <jtml@losalamos.com>
Date: Mon, 02 Feb 2015 23:06:51 -0700
Last week I read with interest the discussion here. There were numerous replies, each with a bit of good information. Gary, K4FMX, nailed it spot on, with this explanation reproduced here. This agree
/archives//html/Amps/2015-02/msg00016.html (8,425 bytes)

288. [Amps] Chippewa amplifier (score: 1)
Author: John Lyles <jtml@losalamos.com>
Date: Sat, 21 Mar 2015 23:58:03 -0600
On ebay, I saw a Chippewa model KL-1 without power supply, pair 4-400A, 1960: http://www.ebay.com/itm/Rare-Vintage-Heathkit-Tube-Linear-Amplifier-Chippewa-KL-1-for-Ham-Radio-/281630963209?pt=LH_Defau
/archives//html/Amps/2015-03/msg00054.html (6,648 bytes)

289. [Amps] Chippewa amplifier (score: 1)
Author: John Lyles <jtml@losalamos.com>
Date: Wed, 25 Mar 2015 22:40:13 -0600
The SB220 is considered by many to be a light to medium duty amplifier, as the cooling fan and the voltage doubler power supply cannot support operating those 3-500Z key down for significant time. I
/archives//html/Amps/2015-03/msg00065.html (9,245 bytes)

290. [Amps] oil vs distilled water cooling. (score: 1)
Author: John Lyles <jtml@losalamos.com>
Date: Wed, 15 Apr 2015 21:57:07 -0600
water can be found in 4 litre jugs, cheap, at any grocery store. To the best of my knowledge, distilled water will extract heat a lot faster / better than oil. I only saw 1-2 small tubes in the enti
/archives//html/Amps/2015-04/msg00112.html (10,893 bytes)

291. [Amps] Oil v water cooling (score: 1)
Author: John Lyles <jtml@losalamos.com>
Date: Fri, 17 Apr 2015 14:44:05 -0600
On 4/17/15 10:00 AM, amps-request@contesting.com wrote: Hi, I believe that not all "distilled water" is suitable for this, you may need to specify "deionised water". The water conductivity needs regu
/archives//html/Amps/2015-04/msg00121.html (11,115 bytes)

292. [Amps] tetrode push-pull amp schematics (score: 1)
Author: John Lyles <jtml@losalamos.com>
Date: Fri, 26 Jun 2015 20:32:31 -0600
I think this thread is old, but have been busy commissioning a new HPA, another pair of Diacrodes (tetrodes) at 200 MHz, class B. Its working now, has consumed me since February, the installation and
/archives//html/Amps/2015-06/msg00072.html (11,434 bytes)

293. [Amps] HV transformer and Variac (score: 1)
Author: John Lyles <jtml@losalamos.com>
Date: Sun, 26 Jul 2015 22:31:45 -0600
Interesting discussion about 'Variacs', one brand known as Powerstats. I wondered about the shorted turn where the wiper contacted, the carbon theory makes most sense. In my workplace, the last of th
/archives//html/Amps/2015-07/msg00154.html (8,042 bytes)

294. Re: [Amps] Regulated filament current (score: 1)
Author: John Lyles <jtml@losalamos.com>
Date: Sun, 6 Sep 2015 02:08:08 -0600
I agree with W8ZR's recommendation for regulation if it is used for filament power. I spoke with a high power tube application engineer at one of the manufacturers a couple years ago. He considered t
/archives//html/Amps/2015-09/msg00020.html (11,734 bytes)

295. Re: [Amps] Regulated filament current (score: 1)
Author: John Lyles <jtml@losalamos.com>
Date: Mon, 7 Sep 2015 00:42:28 -0600
After reading several replies and my email from yesterday about this, I realized that a clarification is due along with further topics. When we talk about regulated filament current or voltage, we ma
/archives//html/Amps/2015-09/msg00024.html (11,075 bytes)

296. [Amps] Regulated filament current (score: 1)
Author: John Lyles <jtml@losalamos.com>
Date: Tue, 8 Sep 2015 17:35:49 -0600
The effect of increasing anode (and cathode) current in an amplifier tube shouldn't be a source for increasing temperature in the heater. However, as it may be the result of increasing RF drive, and
/archives//html/Amps/2015-09/msg00026.html (8,740 bytes)

297. [Amps] WTB 220 mhz amp/ Eimac question (score: 1)
Author: John Lyles <jtml@losalamos.com>
Date: Sun, 8 Nov 2015 21:11:11 -0700
Ever since Reid Brandon was let go at CPI/Eimac, there hasn't been ham presence there. Or at least I haven't heard of any. Can you at least hi pot test that tube, after ohmmeter for obvious causes li
/archives//html/Amps/2015-11/msg00030.html (8,542 bytes)

298. [Amps] Tube wear out phenomena (score: 1)
Author: John Lyles <jtml@losalamos.com>
Date: Sun, 20 Dec 2015 23:17:49 -0700
Thorium is added at the 1% level to pure tungsten, to improve efficiency of electron emission from the filament of direct heated tubes. It allows a reduction of the temperature of a filament and redu
/archives//html/Amps/2015-12/msg00041.html (11,855 bytes)

299. [Amps] Tube wear out phenomena (score: 1)
Author: John Lyles <jtml@losalamos.com>
Date: Fri, 25 Dec 2015 15:40:01 -0700
I read the link below; my comments come from discussions with the direct tube engineers and application engineers with RCA, Eimac. E2V, and Thales (Thomson). I was at Thales factory for a week last m
/archives//html/Amps/2015-12/msg00060.html (9,697 bytes)

300. [Amps] SB 220 Exploding Resistor (score: 1)
Author: John Lyles <jtml@losalamos.com>
Date: Mon, 18 Jan 2016 14:13:10 -0700
If you get a strong enough wirewound resistor, this can suffice as the surge current limiting resistor for a spark over in a tube. With 250 amps at the beginning of the overcurrent (2500 V/10 ohms) s
/archives//html/Amps/2016-01/msg00037.html (10,141 bytes)

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