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References: [ +from:Peter.Chadwick@gpsemi.com: 141 ]

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121. No subject (score: 1): Author: Peter.Chadwick@gpsemi.com (Peter Chadwick); Date: Tue, 17 Jun 1997 14:01:00 +0100; First, it would draw a lot of current, assuming that it's a tube that will draw lots of current with Vg at zero. Second, if it's a tube with a cathode (4CX250 etc) as opposed to a filament (4-400, 4-; /archives//html/Amps/1997-06/msg00247.html (8,507 bytes)
122. [AMPS] re 2 tone (score: 1): Author: Peter.Chadwick@gpsemi.com (Peter Chadwick); Date: Tue, 17 Jun 1997 14:20:00 +0100; Tom, Not having found one that has an rx that is much better than what I've got, I tend to forget that the modern rigs are pretty awful! Of course, you're right. I use a much modified FT102, with a 1; /archives//html/Amps/1997-06/msg00248.html (6,779 bytes)
123. [AMPS] failure (score: 1): Author: Peter.Chadwick@gpsemi.com (Peter Chadwick); Date: Tue, 17 Jun 1997 15:04:00 +0100; filament enough I think the 8122 has a cathode rather than a filament, so my guess is that it drew a lot of current while the cathode cooled down, which takes some time. I suppose its possible that i; /archives//html/Amps/1997-06/msg00249.html (7,891 bytes)
124. [AMPS] failure (score: 1): Author: Peter.Chadwick@gpsemi.com (Peter Chadwick); Date: Tue, 17 Jun 1997 17:03:00 +0100; Even with bias, you don't want to have screen volts without plate volts. I know of an old (now) military tx which had a 5894 driving a pair of 4-250As. The plate voltage for the 5894 was the screen f; /archives//html/Amps/1997-06/msg00252.html (8,374 bytes)
125. [AMPS] AB1/2 (score: 1): Author: Peter.Chadwick@gpsemi.com (Peter Chadwick); Date: Wed, 18 Jun 1997 11:49:00 +0100; Gas tube regulators. Someone asked about the dynamic impedance of gas tube regulators. I found some RCA info which suggests about 160 ohms - that's for 105 and 150 volt regulators, both the octals an; /archives//html/Amps/1997-06/msg00257.html (9,448 bytes)
126. [AMPS] SB220 (score: 1): Author: Peter.Chadwick@gpsemi.com (Peter Chadwick); Date: Wed, 18 Jun 1997 16:01:00 +0100; Harbach Electronics web page is at www.harbach.com/ 73 de G3RZP -- FAQ on WWW: http://www.contesting.com/ampfaq.html Submissions: amps@contesting.com Administrative requests: amps-REQUEST@contesting.; /archives//html/Amps/1997-06/msg00260.html (6,600 bytes)
127. [AMPS] failure (score: 1): Author: Peter.Chadwick@gpsemi.com (Peter Chadwick); Date: Wed, 18 Jun 1997 16:25:00 +0100; Tom Something at the back of my mind says that I've seen somewhere that one shouldn't run a thoriated filament in saturation, but I can't remember why - the penalty of getting old, I guess. If you ru; /archives//html/Amps/1997-06/msg00263.html (7,973 bytes)
128. [AMPS] re failures (score: 1): Author: Peter.Chadwick@gpsemi.com (Peter Chadwick); Date: Thu, 19 Jun 1997 09:53:00 +0100; I guess that we're all agreed that a cathode (as opposed to a filament) is likely to be seriously damaged under the proposed bias/filament supply failure scenario, and that some form of interlocking; /archives//html/Amps/1997-06/msg00278.html (8,460 bytes)
129. No subject (score: 1): Author: Peter.Chadwick@gpsemi.com (Peter Chadwick); Date: Thu, 19 Jun 1997 11:09:00 +0100; Mike, YO3CTK In the UK, bitter beer - a 4 - 5% alcohol beer, not a lager. In the US, Sam Adams or the microbrewery productions. In Bavaria, Paulaner Brau. In OK land, Budweiser (not the American vers; /archives//html/Amps/1997-06/msg00279.html (7,407 bytes)
130. [AMPS] failures (score: 1): Author: Peter.Chadwick@gpsemi.com (Peter Chadwick); Date: Thu, 19 Jun 1997 15:21:00 +0100; Rich, you say: on? It is leakage reactance, as opposed to winding resistance that limits the current? If so, what's the power factor, or doesn't one worry? 73 Peter G3RZP -- FAQ on WWW: http://www.co; /archives//html/Amps/1997-06/msg00285.html (6,982 bytes)
131. [AMPS] Delrin,failures, etc (score: 1): Author: Peter.Chadwick@gpsemi.com (Peter Chadwick); Date: Fri, 20 Jun 1997 10:28:00 +0100; I wouldn't even recommend it for spreaders, unless you're looking to replace them every few years because of the ultra violet degradation. But how about an application as an RF firelighter? Tom comme; /archives//html/Amps/1997-06/msg00297.html (10,616 bytes)
132. [AMPS] neutralising (score: 1): Author: Peter.Chadwick@gpsemi.com (Peter Chadwick); Date: Fri, 20 Jun 1997 12:10:00 +0100; Bill, If you have a triode with a tuned plate, and feedback through the plate grid capacity, you get a pure capacitive input at resonance. Off resonance, the input admittance of the tube is an impeda; /archives//html/Amps/1997-06/msg00298.html (9,268 bytes)
133. [AMPS] spreaders (score: 1): Author: Peter.Chadwick@gpsemi.com (Peter Chadwick); Date: Fri, 20 Jun 1997 14:09:00 +0100; My preference is for PTFE (Teflon) or ceramic. Over here, of course, we don't get Californian sunshine, but even so, I've been disappointed in delrin, Nylon, polycarbonate and perspex (trade name - t; /archives//html/Amps/1997-06/msg00307.html (7,807 bytes)
134. [AMPS] neutralising (score: 1): Author: Peter.Chadwick@gpsemi.com (Peter Chadwick); Date: Fri, 20 Jun 1997 14:32:00 +0100; Tom, you say: Interesting comment. I'm not totally sure that companies like Marconi, Collins, Racal etc would agree. On the other hand, I may be trying to apply your comment to auto tuned professiona; /archives//html/Amps/1997-06/msg00308.html (8,210 bytes)
135. [AMPS] Power off (score: 1): Author: Peter.Chadwick@gpsemi.com (Peter Chadwick); Date: Wed, 25 Jun 1997 12:23:00 +0100; In our labs Jim, kit gets switched off every evening. Computers and work stations are another thing: frequently the work stations are running simulations overnight, but PCs are generally switched off; /archives//html/Amps/1997-06/msg00350.html (7,483 bytes)
136. [AMPS] filament trips (score: 1): Author: Peter.Chadwick@gpsemi.com (Peter Chadwick); Date: Wed, 25 Jun 1997 14:54:00 +0100; Rich, AG6K, You recommend a fil undervoltage trip based on a 723. Can you expand on this? Is the 723 (which is a regulator) providing a reference source for a comparator, with the filament volts rect; /archives//html/Amps/1997-06/msg00351.html (6,804 bytes)
137. [AMPS] fil regulators/trips (score: 1): Author: Peter.Chadwick@gpsemi.com (Peter Chadwick); Date: Thu, 26 Jun 1997 09:20:00 +0100; Rich, Thanks for the expansion. My experience with 723s (backed up by a fair number of engineers who've had similar problems) is that they are very prone to RF pickup. I knew a guy who could never ge; /archives//html/Amps/1997-06/msg00353.html (7,312 bytes)
138. [AMPS] 723 (score: 1): Author: Peter.Chadwick@gpsemi.com (Peter Chadwick); Date: Thu, 26 Jun 1997 10:37:00 +0100; Rich, you say; Don't agree. For RF fields picked up on the chip ( and we've done some measurements on that) the 100K resistors don't do anything. In fact, they increase the impedance that is seen loo; /archives//html/Amps/1997-06/msg00355.html (8,345 bytes)
139. [AMPS] regulators (score: 1): Author: Peter.Chadwick@gpsemi.com (Peter Chadwick); Date: Fri, 27 Jun 1997 09:09:00 +0100; I looked up the 723, and the maximum suggested resistors are 10K. The National data sheet doesn't give the input bias currents, but judging by the time the 723 has been around, bias currents and offs; /archives//html/Amps/1997-06/msg00361.html (10,253 bytes)
140. [AMPS] regulators (score: 1): Author: Peter.Chadwick@gpsemi.com (Peter Chadwick); Date: Fri, 27 Jun 1997 14:42:00 +0100; Tom, All chips are devils. They are all designed by people of dubious intellect and moral fibre, using processes more akin to black magic than science, including in many cases, a strange belief in si; /archives//html/Amps/1997-06/msg00364.html (7,865 bytes)

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