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References: [ +from:Peter.Chadwick@zarlink.com: 335 ]

Total 335 documents matching your query.

261. Re: [Amps] 3.5 kV 2A REGULATED Power Supply: Schematic ? (score: 1)
Author: peter.chadwick@Zarlink.Com
Date: Mon, 5 Jan 2004 11:37:05 +0000
I have found problems when using high impedance supplies with 6146s, especially as they get older. Especially bad is the Yaesu 'anti flash over diode' in series with the screen grid - any negative sc
/archives//html/Amps/2004-01/msg00042.html (9,038 bytes)

262. [Amps] Step start resistors (score: 1)
Author: peter.chadwick@Zarlink.Com
Date: Mon, 5 Jan 2004 11:41:21 +0000
Any ideas on what values to use for step start resistors? In the past, I've tended to choose a value from the available stock - something like 50 ohms, 100 watts, which limits the surge current to ju
/archives//html/Amps/2004-01/msg00043.html (6,710 bytes)

263. Re: [Amps] 3.5 kV 2A REGULATED Power Supply: Schematic ? (score: 1)
Author: peter.chadwick@Zarlink.Com
Date: Mon, 5 Jan 2004 13:53:15 +0000
I didn't make it clear that the 'low impedance' screen supply means low impedance both for source and sink - i.e good regulation for both source and sink.. For 6146B's, I use zeners - not ideal, but
/archives//html/Amps/2004-01/msg00048.html (11,548 bytes)

264. Re: [Amps] Step Start PhaseAngle cotrollers (score: 1)
Author: peter.chadwick@Zarlink.Com
Date: Wed, 7 Jan 2004 13:00:17 -0800
relay stepstart is a less I rather go along with Rich on this one. For HV supplies, I go along with him about the use of thermisters, too, although for filament inrush limiting, that seems a good app
/archives//html/Amps/2004-01/msg00081.html (7,461 bytes)

265. Re: [Amps] Re: FW: How are IMds created (score: 1)
Author: peter.chadwick@Zarlink.Com
Date: Wed, 7 Jan 2004 16:12:53 -0800
If the IMD products were the mixing of the harmonics, it should be possible to trap them out. Pappenfus et al point out the fallacy of regarding IMDs as being the mixing of the harmonics: it is howev
/archives//html/Amps/2004-01/msg00086.html (7,587 bytes)

266. Re: [Amps] Power-off tube cooling (score: 1)
Author: peter.chadwick@Zarlink.Com
Date: Mon, 19 Jan 2004 14:14:04 +0000
The 4CX1000 data sheet says it needs cooling air at the same time as the application of heater volts. Frightening to realise that the 4X150/4X250 basic design is older than I am, it being in producti
/archives//html/Amps/2004-01/msg00194.html (7,753 bytes)

267. RE: [Amps] Transformer varnish removal (score: 1)
Author: peter.chadwick@Zarlink.Com
Date: Wed, 21 Jan 2004 09:12:14 +0000
Soemwhat easier and more controllable is caustic soda (sodium hydroxide). Readily available (or at least was - I wouldn't bet on it still being so with the modern environmental police) for drain clea
/archives//html/Amps/2004-01/msg00213.html (8,405 bytes)

268. Re: [Amps] HV SAFETY QUESTION (score: 1)
Author: peter.chadwick@Zarlink.Com
Date: Mon, 2 Feb 2004 15:33:05 +0000
The question was asked Not as such. The story I was told from someone who worked at the factory, that a large 275kV transformer ( 100+tons) was tested and the insulation test left a charge on one of
/archives//html/Amps/2004-02/msg00012.html (7,612 bytes)

269. Re: [Amps] 6LQ6 Input Impedance (score: 1)
Author: peter.chadwick@Zarlink.Com
Date: Mon, 16 Feb 2004 16:03:08 +0000
Bill asks: Under what conditions? Class A, grounded grid, about 120 ohms ( in class A grounded grid, Rin = 1/gm) Grounded cathode, 22pF at low frequencies: at HF, cathode lead inductance will modify
/archives//html/Amps/2004-02/msg00132.html (7,111 bytes)

270. Re: [Amps] tube cooling (score: 1)
Author: peter.chadwick@Zarlink.Com
Date: Wed, 18 Feb 2004 09:00:19 +0000
Plain bearings are quieter than ball bearings, but generally don't last as long before they start wearing and get noisy. If you can get 'Oilite' sleeved bearings, they last pretty well and don't need
/archives//html/Amps/2004-02/msg00160.html (8,253 bytes)

271. Re: [Amps] Looking for pre-amps (score: 1)
Author: peter.chadwick@Zarlink.Com
Date: Thu, 4 Mar 2004 09:20:46 -0800
I tried push pull source followers with a 2 turn loop about 1 metre square. Unfortunately, I got about 80 volts rms across the tuned loop, and the source followers departed this life very rapidly....
/archives//html/Amps/2004-03/msg00045.html (7,162 bytes)

272. Re: [Amps] Johnson Thunderbolt questions (score: 1)
Author: peter.chadwick@Zarlink.Com
Date: Mon, 15 Mar 2004 08:23:37 +0000
Don't know about the Thunderbolt specifically, but my experience with the 4-400 and 4-250 family is that 2 to 2.5kV isn't really enough to get more than about 400 to 500 watts PEP out in AB1. Both tu
/archives//html/Amps/2004-03/msg00171.html (7,559 bytes)

273. Re: [Amps] SB-221 Why is the the variable load capacitor onlycrimpedto the ... (score: 1)
Author: peter.chadwick@Zarlink.Com
Date: Mon, 5 Apr 2004 10:23:09 +0100
crimped, I believe they've learned the hard way in the US not to crimp aluminium cables, though........... 73 Peter G3RZP _______________________________________________ Amps mailing list Amps@contes
/archives//html/Amps/2004-04/msg00033.html (7,525 bytes)

274. Re: [Amps] tuned choke (score: 1)
Author: peter.chadwick@Zarlink.Com
Date: Mon, 5 Apr 2004 10:36:35 +0100
This somewhat puzzles me. I would have expected it to be tuned higher in frequency ( although maybe no more than 0.5 to 1 Hz) so that it looked very inductive under no load conditions. As the load in
/archives//html/Amps/2004-04/msg00034.html (6,859 bytes)

275. Re: [Amps] SB221: Can you saftely mix and run an Eimac 3-500Z withand RF Par... (score: 1)
Author: peter.chadwick@Zarlink.Com
Date: Mon, 5 Apr 2004 14:51:43 +0100
with silver solder, I'm not sure exactly what Rich means by 'silver solder' in this context. If he means the high temperature ( 600 - 800 deg C) stuff we use for model steam engine boilers and fittin
/archives//html/Amps/2004-04/msg00037.html (8,327 bytes)

276. Re: [Amps] Alpha PA-76 (score: 1)
Author: peter.chadwick@Zarlink.Com
Date: Tue, 13 Apr 2004 07:57:32 +0100
matter. That depends on the time delay you need - leakage in a normal electrolytic may be too much if you want a longish delay. Somewhere, I have some MPF121if you really want to try, but I've just g
/archives//html/Amps/2004-04/msg00086.html (7,353 bytes)

277. Re: [Amps] Serious design stage (score: 1)
Author: peter.chadwick@Zarlink.Com
Date: Wed, 21 Apr 2004 09:11:52 +0200
done. I've seen a number of professional tx's in which it was done. One of them was pretty massive - it had a pair of 813s modulated by a pair, and took two 6 foot high 19 inch wide racks. The main H
/archives//html/Amps/2004-04/msg00130.html (7,625 bytes)

278. Re: [Amps] Serious design stage (score: 1)
Author: peter.chadwick@Zarlink.Com
Date: Thu, 22 Apr 2004 09:22:38 +0200
In that case, how about the 872? It's a sort of big brother to the 866. But this is one application where I'd go solid state. One problem with big mercury vapour (and even big xenon) rectifiers was t
/archives//html/Amps/2004-04/msg00146.html (8,678 bytes)

279. Re: [Amps] Serious design stage (score: 1)
Author: peter.chadwick@Zarlink.Com
Date: Fri, 23 Apr 2004 09:01:49 +0200
I thought these days that Pacific G & E (I'm told that's 'Pacific Graft and Extrortion!') was charging so much for electricity that very few could afford to run a 'California kilowatt' any more. 73 P
/archives//html/Amps/2004-04/msg00158.html (8,230 bytes)

280. Re: [Amps] new amplifier results (score: 1)
Author: peter.chadwick@Zarlink.Com
Date: Mon, 26 Apr 2004 08:05:41 +0100
John Lyles asked: Yes. 73 Peter G3RZP _______________________________________________ Amps mailing list Amps@contesting.com http://lists.contesting.com/mailman/listinfo/amps
/archives//html/Amps/2004-04/msg00204.html (6,832 bytes)


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