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References: [ +from:Peter_Chadwick@mitel.com: 967 ]

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261. [AMPS] Amp using 833A (score: 1): Author: Peter_Chadwick@mitel.com (Peter Chadwick); Date: Mon, 25 Sep 2000 16:09:42 +0100; No, it's application of tube technology. A tube that will do push-pull AB2 audio will do parallel or push pull AB2 RF. There's nothing magic in parallel v. push-pull when tuned tank circuits are used; /archives//html/Amps/2000-09/msg00988.html (9,546 bytes)
262. [AMPS] Amp using 833A (score: 1): Author: Peter_Chadwick@mitel.com (Peter Chadwick); Date: Tue, 26 Sep 2000 08:43:51 +0100; In AB, where conduction is defined as more than 180 degrees(AB1 is conduction of more than 180 degrees without grid current, AB2 is conduction of more than 180 degrees with grid current), the zero cr; /archives//html/Amps/2000-09/msg01009.html (8,883 bytes)
263. [AMPS] Amp using 833A (score: 1): Author: Peter_Chadwick@mitel.com (Peter Chadwick); Date: Tue, 26 Sep 2000 08:50:25 +0100; Agreed, that can be a problem. It doesn't seem to me that desirable a feature, (although necessary from a PA solid state fuse protection point of view) but I guess that's why so many rigs build in a; /archives//html/Amps/2000-09/msg01010.html (8,395 bytes)
264. [AMPS] Linearizing Linears, feedback or feedforward (score: 1): Author: Peter_Chadwick@mitel.com (Peter Chadwick); Date: Tue, 26 Sep 2000 10:22:10 +0100; It's actually 1964. There's an awful amount in there about applying NFB in tube linears, over one, two and three stages too. Not an easily available book, but a super one. I wouldn't be without mine.; /archives//html/Amps/2000-09/msg01011.html (11,886 bytes)
265. [AMPS] wanted SB 220 bandswitch (score: 1): Author: Peter_Chadwick@mitel.com (Peter Chadwick); Date: Tue, 26 Sep 2000 10:44:56 +0100; I think Ian has a point here. Leaving out any surmise about parasitics, the costs of switches are such that a number of amps are somewhat marginally rated in that area. Some commercial transmitters t; /archives//html/Amps/2000-09/msg01014.html (8,383 bytes)
266. [AMPS] Book recommendation? (score: 1): Author: Peter_Chadwick@mitel.com (Peter Chadwick); Date: Tue, 26 Sep 2000 10:53:55 +0100; Jose, I would recommend 'Single Sideband Principals and Circuits', by Pappenfus, Bruene and Schoenike, published by McGraw Hill in 1964. Library of Congress card number 63-13938. It has the advantage; /archives//html/Amps/2000-09/msg01016.html (7,966 bytes)
267. [AMPS] New member and Drake L7 questions (score: 1): Author: Peter_Chadwick@mitel.com (Peter Chadwick); Date: Tue, 26 Sep 2000 10:58:51 +0100; Doesn't mean they're still made - look at integrated circuits in components catalogues! 100mV was the BS at one time, and I believe, was suggested for IEC. Depends on where the meter is in the circui; /archives//html/Amps/2000-09/msg01017.html (8,972 bytes)
268. SV: [AMPS] Linearizing Linears, feedback or feedforward (score: 1): Author: Peter_Chadwick@mitel.com (Peter Chadwick); Date: Tue, 26 Sep 2000 13:47:52 +0100; Capacitive feedback in grounded cathode circuits can work well - BUT:- In the 'standard' Bruene neutralising circuit, where a grid tuned circuit has one end to the grid and the cold end via a capacit; /archives//html/Amps/2000-09/msg01024.html (10,715 bytes)
269. [AMPS] Book recommendation? (score: 1): Author: Peter_Chadwick@mitel.com (Peter Chadwick); Date: Tue, 26 Sep 2000 14:50:29 +0100; the Unfortunately for our purposes, the revision doesn't go into tube amps in the same detail as the original. It's still worth having, but I don't have it as far up my 'must have' list. 73 Peter G3R; /archives//html/Amps/2000-09/msg01027.html (7,288 bytes)
270. SV: [AMPS] Linearizing Linears, feedback or feedforward (score: 1): Author: Peter_Chadwick@mitel.com (Peter Chadwick); Date: Tue, 26 Sep 2000 15:24:17 +0100; I obviously didn't make myself clear. I was musing along the lines of 'it was done in the 30L1 for another reason that is not immediately apparent', rather than 'this is an approach designed to give; /archives//html/Amps/2000-09/msg01030.html (10,715 bytes)
271. [AMPS] RE:30L1/30S1 tuning (was: linearizing linears) (score: 1): Author: Peter_Chadwick@mitel.com (Peter Chadwick); Date: Tue, 26 Sep 2000 15:31:47 +0100; The idea is to measure the ratio of RF plate volts to RF grid volts. If the loading is too light - plate load impedance too high - there's too many RF volts on the plate. Conversely, if too heavy, th; /archives//html/Amps/2000-09/msg01031.html (7,452 bytes)
272. SV: [AMPS] Linearizing Linears, feedback or feedforward (score: 1): Author: Peter_Chadwick@mitel.com (Peter Chadwick); Date: Tue, 26 Sep 2000 16:02:57 +0100; Another possible reason for the 220pF grid to ground in the 30L1 comes to mind. 220pF and 125 nH resonate about 30MHz. The grid structure inductance plus socket plus capacitor lead length could just; /archives//html/Amps/2000-09/msg01034.html (10,091 bytes)
273. SV: [AMPS] Linearizing Linears, feedback or feedforward (score: 1): Author: Peter_Chadwick@mitel.com (Peter Chadwick); Date: Tue, 26 Sep 2000 17:08:57 +0100; As Rich would say, verily. I suspect part of the problem is that the 811 isn't really an RF tube - at least not above 15MHz or so. 73 Peter G3RZP -- FAQ on WWW: http://www.contesting.com/FAQ/amps Sub; /archives//html/Amps/2000-09/msg01047.html (9,989 bytes)
274. SV: [AMPS] Linearizing Linears, feedback or feedforward (score: 1): Author: Peter_Chadwick@mitel.com (Peter Chadwick); Date: Tue, 26 Sep 2000 17:20:40 +0100; you surprise me. Surely wouldn't be my first choice - or second.....even though they're rated to 60MHz at full input. So, for that matter, are 807s. Are they stable enough in linear service not to ha; /archives//html/Amps/2000-09/msg01049.html (9,842 bytes)
275. SV: [AMPS] Linearizing Linears, feedback or feedforward (score: 1): Author: Peter_Chadwick@mitel.com (Peter Chadwick); Date: Wed, 27 Sep 2000 09:20:30 +0100; There was an early VHF transceiver for the RAF (late 1940) that used a specially selected 807 (called an 8018) at 120MHz. It was sort of Class C, but they modulated the driver - don't know why. Still; /archives//html/Amps/2000-09/msg01081.html (10,014 bytes)
276. SV: [AMPS] Linearizing Linears, feedback or feedforward (score: 1): Author: Peter_Chadwick@mitel.com (Peter Chadwick); Date: Wed, 27 Sep 2000 09:23:26 +0100; How much DC input, though? I bet a pair of 7193s or an RK34 would be more efficient. 73 Peter G3RZP -- FAQ on WWW: http://www.contesting.com/FAQ/amps Submissions: amps@contesting.com Administrative r; /archives//html/Amps/2000-09/msg01082.html (9,875 bytes)
277. [AMPS] Drake L7: it WORKS :-)! (score: 1): Author: Peter_Chadwick@mitel.com (Peter Chadwick); Date: Wed, 27 Sep 2000 10:07:15 +0100; 73 Peter G3RZP -- FAQ on WWW: http://www.contesting.com/FAQ/amps Submissions: amps@contesting.com Administrative requests: amps-REQUEST@contesting.com Problems: owner-amps@contesting.com; /archives//html/Amps/2000-09/msg01083.html (7,182 bytes)
278. SV: [AMPS] Linearizing Linears, feedback or feedforward (score: 1): Author: Peter_Chadwick@mitel.com (Peter Chadwick); Date: Wed, 27 Sep 2000 13:50:45 +0100; I really can't remember if it had back then - we are talking of over 30 years ago. I found it quite a good magazine in those days, despite Wayne's ramblings. I gave up when it went mad on FM and repe; /archives//html/Amps/2000-09/msg01091.html (9,582 bytes)
279. [AMPS] AL-80B Amps (score: 1): Author: Peter_Chadwick@mitel.com (Peter Chadwick); Date: Wed, 27 Sep 2000 14:01:21 +0100; You guys are not seriously suggesting that a radio amateur should be required to know a little bit about radio and radio equipment, are you? Shame on you! You'll be suggesting that amateurs be allowe; /archives//html/Amps/2000-09/msg01094.html (8,856 bytes)
280. SV: [AMPS] Linearizing Linears, feedback or feedforward (score: 1): Author: Peter_Chadwick@mitel.com (Peter Chadwick); Date: Wed, 27 Sep 2000 15:08:55 +0100; As Colin says, a model of efficiency! Somehow, I don't get convinced that these big old tubes with long internal leads are really the best choices for use at the higher frequencies. 73 Peter G3RZP --; /archives//html/Amps/2000-09/msg01097.html (9,384 bytes)

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