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281. Re: [Amps] AL-80B Trouble (score: 1)
Author: "Tom W8JI" <w8ji@w8ji.com>
Date: Sat, 26 Aug 2006 17:29:42 -0400
what was happening. He most emphatically admonished me to write this guy in California for the nichrome supressor kit or I'd lose another tube in short order. I'd never even heard of nichrome, but I
/archives//html/Amps/2006-08/msg00680.html (10,779 bytes)

282. Re: [Amps] Parasitics & Filament Sag (score: 1)
Author: "Tom W8JI" <w8ji@w8ji.com>
Date: Sat, 26 Aug 2006 20:31:19 -0400
In random tests when an unknown intermittent problem occurs, no change at all can result in what people perceive as a cure. This why double blind tests are done. The random coincidence effect is why
/archives//html/Amps/2006-08/msg00686.html (10,199 bytes)

283. Re: [Amps] Parasitics & Filament Sag (score: 1)
Author: "Tom W8JI" <w8ji@w8ji.com>
Date: Sun, 27 Aug 2006 14:18:12 -0400
Mikey, I don't Joe was the first to cast that stone. Why be so rough on him? 73 Tom _______________________________________________ Amps mailing list Amps@contesting.com http://lists.contesting.com/
/archives//html/Amps/2006-08/msg00716.html (9,669 bytes)

284. Re: [Amps] Parasitics & Filament Sag (score: 1)
Author: "Tom W8JI" <w8ji@w8ji.com>
Date: Sun, 27 Aug 2006 15:06:56 -0400
Actually Paul Hrivnak of Vectronics, when he was convinced the glass in Chinese 3-500's was melting from parasitics, included a nichrome hairpin in his single 3-500Z amp. The amp kept melting holes
/archives//html/Amps/2006-08/msg00721.html (11,277 bytes)

285. Re: [Amps] Parasitics & Filament Sag (score: 1)
Author: "Tom W8JI" <w8ji@w8ji.com>
Date: Sun, 27 Aug 2006 15:15:16 -0400
That is electrically impossible. There is only so much emission available, and the force from even many dozens of amperes is in the order of grams. It is nearly impossible from filament inrush, it i
/archives//html/Amps/2006-08/msg00723.html (8,170 bytes)

286. Re: [Amps] filament forces TSPA (score: 1)
Author: "Tom W8JI" <w8ji@w8ji.com>
Date: Sun, 27 Aug 2006 20:21:30 -0400
No doubt. Just run a few thousand amperes through it. _______________________________________________ Amps mailing list Amps@contesting.com http://lists.contesting.com/mailman/listinfo/amps
/archives//html/Amps/2006-08/msg00727.html (6,911 bytes)

287. [Amps] Filament forces (score: 1)
Author: "Tom W8JI" <w8ji@w8ji.com>
Date: Sun, 27 Aug 2006 22:10:51 -0400
For those who are interested: 1.) The filament starting current can easily be 30 or 40 amperes RMS (50 amperes peak) for thousands of turn on filament cycles and not cause damage. As a matter of fact
/archives//html/Amps/2006-08/msg00729.html (8,537 bytes)

288. Re: [Amps] Parasitics & Filament Sag (score: 1)
Author: "Tom W8JI" <w8ji@w8ji.com>
Date: Tue, 29 Aug 2006 05:41:15 -0400
unconditionally stable because the grid has a positive input resistance. If the grid is tuned LF of the plate, it has a negative input resistance. On this basis then, a tube with a good short grid co
/archives//html/Amps/2006-08/msg00757.html (11,173 bytes)

289. Re: [Amps] Parasitics & Filament Sag (score: 1)
Author: "Tom W8JI" <w8ji@w8ji.com>
Date: Tue, 29 Aug 2006 14:51:46 -0400
That's exactly opposite the truth anyway. The most stable tubes are those with the highest operating frequency limits. 73 Tom _______________________________________________ Amps mailing list Amps@c
/archives//html/Amps/2006-08/msg00779.html (9,919 bytes)

290. Re: [Amps] TL-922 question (score: 1)
Author: "Tom W8JI" <w8ji@w8ji.com>
Date: Tue, 29 Aug 2006 15:06:21 -0400
You can go all the way down to a few hundered pF on the blocker and it will make very little difference in tuning. It is at a few thousand ohm impedance point. If the blocker was so bad as to affect
/archives//html/Amps/2006-08/msg00780.html (9,069 bytes)

291. Re: [Amps] TL-922 question (score: 1)
Author: "Tom W8JI" <w8ji@w8ji.com>
Date: Tue, 29 Aug 2006 21:35:11 -0400
Joe and Tom, While the tuning cap meshes very slightly more, the loading cap decreases noticeably in required size as drive power is increased. For example with a effective network Q of 12 and 3000
/archives//html/Amps/2006-08/msg00788.html (9,594 bytes)

292. Re: [Amps] Heat spreader for solid-state amps (score: 1)
Author: "Tom W8JI" <w8ji@w8ji.com>
Date: Tue, 29 Aug 2006 21:47:55 -0400
I'm having a difficult time following the logic in that. I don't believe that point could ever be reached. It would require a fast-attack slow-decay copper. The temperature rise time should be the s
/archives//html/Amps/2006-08/msg00789.html (8,122 bytes)

293. Re: [Amps] Parasitics & Filament Sag (score: 1)
Author: "Tom W8JI" <w8ji@w8ji.com>
Date: Wed, 30 Aug 2006 05:57:25 -0400
It's easy to see the series resistance added by the nichrome primarily affects low frequency performance, and has a decreasing effect as frequency is increased. The correct term for a nichrome suppr
/archives//html/Amps/2006-08/msg00794.html (10,388 bytes)

294. Re: [Amps] Parasitics & Filament Sag (score: 1)
Author: "Tom W8JI" <w8ji@w8ji.com>
Date: Wed, 30 Aug 2006 07:40:20 -0400
That can be because of relay sequencing. Known to be a problem in the stock TL922. Because of bypass caps and other component values, the ringing can never have a higher peak at VHF than it has at H
/archives//html/Amps/2006-08/msg00800.html (10,461 bytes)

295. Re: [Amps] Suppressors (score: 1)
Author: "Tom W8JI" <w8ji@w8ji.com>
Date: Wed, 30 Aug 2006 07:55:27 -0400
Every suppressor, even a parallel R and silver L, behaves similar. They just have slightly different slopes in impedance. When we compare a nichrome suppressor to an equally VHF sized conventional s
/archives//html/Amps/2006-08/msg00801.html (9,917 bytes)

296. Re: [Amps] Cutting G-10 Board (score: 1)
Author: "Tom W8JI" <w8ji@w8ji.com>
Date: Wed, 30 Aug 2006 15:15:51 -0400
did. These are the ones that you can use a flex shaft hand tool with. I can't imagine cutting G-10 with anything that powders it up or shreds it. We have a couple zip routers and they are last resort
/archives//html/Amps/2006-08/msg00822.html (8,847 bytes)

297. Re: [Amps] Parasitics & Filament Sag (score: 1)
Author: "Tom W8JI" <w8ji@w8ji.com>
Date: Wed, 30 Aug 2006 19:45:04 -0400
I can't, except my comments below: It sounds illogical or false to me. One thing we do know for sure is the bias circuit can only charge and cut the tube off at the rate the filament choke common mo
/archives//html/Amps/2006-08/msg00826.html (12,695 bytes)

298. Re: [Amps] Need Japan Radio Plate Transformer Info (score: 1)
Author: "Tom W8JI" <w8ji@w8ji.com>
Date: Fri, 1 Sep 2006 04:51:32 -0400
Ron, Other than insulation requirements which can generally be ignored (since there should be a lot of headroom) here is what happens. You have a transformer designed for 200 V 50 Hz. This means flu
/archives//html/Amps/2006-09/msg00002.html (8,109 bytes)

299. Re: [Amps] Pi-L values (score: 1)
Author: "Tom W8JI" <w8ji@w8ji.com>
Date: Sat, 2 Sep 2006 08:45:22 -0400
How do you know Sunair intends it to behave like a Pi-L and not a double L? By the capacitance ratio? My guess, and it's only a guess, is the stray C from the anode is preventing the network from tr
/archives//html/Amps/2006-09/msg00030.html (9,778 bytes)

300. Re: [Amps] Pi-L values (score: 1)
Author: "Tom W8JI" <w8ji@w8ji.com>
Date: Sat, 2 Sep 2006 15:18:40 -0400
Bob, Are you sure the ARRL handbook is wrong? There are many reactance combinations that will work in that circuit configuration. There are many combinations with the tuning and loading caps at abou
/archives//html/Amps/2006-09/msg00044.html (8,563 bytes)

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