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References: [ +from:4cx250b@miamioh.edu: 327 ]

Total 327 documents matching your query.

301. Re: [Amps] FW: SB220 - 10 Metre input coil adjustment (score: 1)
Author: MU 4CX250B <4cx250b@miamioh.edu>
Date: Sun, 2 Jan 2022 04:09:28 +0000
I agree with Tim. Also, seems to me the grid current is too low. Im going by memory, but for two 3-500Zs, shouldnt it be above 200mA? Possibly the drive is too low? 73, Jim w8zr Sent from my iPhone _
/archives//html/Amps/2022-01/msg00010.html (14,660 bytes)

302. Re: [Amps] Triode metering circuitry (score: 1)
Author: MU 4CX250B <4cx250b@miamioh.edu>
Date: Wed, 5 Jan 2022 20:18:47 -0800
Hi Byron, the 7mA is not grid current, even though it shows on the grid current meter. I believe it rather is the bias current for the zener diode that sets the 8877 resting cathode (zero drive) curr
/archives//html/Amps/2022-01/msg00034.html (10,163 bytes)

303. Re: [Amps] Drake L-7 amplifier power supply requirements (score: 1)
Author: Jim Garland <4cx250b@miamioh.edu>
Date: Tue, 18 Jan 2022 11:11:15 -0700
Larry, do you have a complete circuit diagram of your homebrew HV power supply? If so, you should check and see if the power supply has a B- current return, as opposed to a simple chassis ground conn
/archives//html/Amps/2022-01/msg00054.html (10,912 bytes)

304. Re: [Amps] new Alpha (score: 1)
Author: MU 4CX250B <4cx250b@miamioh.edu>
Date: Sat, 22 Jan 2022 09:31:27 -0500
Ive used two Chinese 8877 tubes for several years. They require slightly more grid current than the Eimac versions, but are otherwise identical. Is there hard evidence that Chinese tubes are inferior
/archives//html/Amps/2022-01/msg00063.html (10,863 bytes)

305. Re: [Amps] Vac relay coils in series ? (score: 1)
Author: MU 4CX250B <4cx250b@miamioh.edu>
Date: Thu, 17 Mar 2022 07:07:35 -0700
Me also. Ive had one coil failure caused by my clumsy effort to clean a coil terminal, and one stuck NC contact, likely caused by my trying to switch a DC voltAge (the RJ1A is intended for RF switchi
/archives//html/Amps/2022-03/msg00026.html (9,060 bytes)

306. Re: [Amps] Why does power output increase? (score: 1)
Author: MU 4CX250B <4cx250b@miamioh.edu>
Date: Sat, 4 Jun 2022 12:03:23 +0000
Victor, do you notice any change in the resting plate current? I dont recall the circuitry of the TL922, but its possible the operating bias point has changed if there is a zener diode in the cathode
/archives//html/Amps/2022-06/msg00002.html (9,857 bytes)

307. Re: [Amps] Why does power output increase? (score: 1)
Author: MU 4CX250B <4cx250b@miamioh.edu>
Date: Sat, 4 Jun 2022 14:18:50 +0000
Victor, I believe low filament voltage is much worse than high filament voltage, at least for tubes with indirectly heated cathodes. I formed this belief after losing the tube in one of my HB amps wh
/archives//html/Amps/2022-06/msg00011.html (12,735 bytes)

308. Re: [Amps] Fw: help (score: 1)
Author: MU 4CX250B <4cx250b@miamioh.edu>
Date: Sat, 22 Oct 2022 11:33:54 -0700
Hi Larry, ALC/AGC circuitry in linear amplifiers was primarily used in the days of vacuum tube, transceivers, which did not have a power output control. With your station, theres no need to use the A
/archives//html/Amps/2022-10/msg00038.html (9,404 bytes)

309. Re: [Amps] Pem Nuts ? (score: 1)
Author: MU 4CX250B <4cx250b@miamioh.edu>
Date: Tue, 25 Oct 2022 07:18:25 -0700
ive used Pem-Nuts many times, most recently on the 160m duo-band amplifier on my website. There are several types, but they all work well Theyre strong, install in a flash, and are convenient. 74, Ji
/archives//html/Amps/2022-10/msg00060.html (8,125 bytes)

310. Re: [Amps] Need reliable source for ACOM2000A tubes GU74B? (score: 1)
Author: MU 4CX250B <4cx250b@miamioh.edu>
Date: Thu, 24 Nov 2022 11:18:37 -0800
I believe John is correct that all GU74b tetrodes date from the Soviet era, whether used or NOS. I was fortunate enough to buy a dozen of them for $360 when demand was still low. I ruined one them by
/archives//html/Amps/2022-11/msg00067.html (11,851 bytes)

311. Re: [Amps] Noisy relay (score: 1)
Author: MU 4CX250B <4cx250b@miamioh.edu>
Date: Sun, 11 Dec 2022 14:48:57 -0800
Steve, you might be hearing the induced voltage kick caused by the inductance of the coil. Try putting a clamping diode. A small signal diode like a 1n914 will work fine, 73, Jim w8zr Sent from my iP
/archives//html/Amps/2022-12/msg00029.html (7,549 bytes)

312. Re: [Amps] .01uf caps across diodes ? (score: 1)
Author: MU 4CX250B <4cx250b@miamioh.edu>
Date: Sun, 11 Dec 2022 22:32:29 -0800
Hi Tim, Ive followed this debate for years and frankly I dont think adding .01uF caps across each diode in a diode string makes much difference one way or the other. Its true that there will be some
/archives//html/Amps/2022-12/msg00034.html (9,327 bytes)

313. Re: [Amps] Noisy relay (score: 1)
Author: MU 4CX250B <4cx250b@miamioh.edu>
Date: Sun, 11 Dec 2022 22:47:31 -0800
Hi Tim, Yes a clamping diode will slow down the release time of a dc relay. The time constant (release time) is approximately L/R, where L is the relay coil inductance and R is the coil resistance. I
/archives//html/Amps/2022-12/msg00035.html (9,646 bytes)

314. Re: [Amps] Noisy relay (score: 1)
Author: MU 4CX250B <4cx250b@miamioh.edu>
Date: Mon, 12 Dec 2022 04:28:10 -0800
Tim, if I understand your question correctly, the diode will have no effect on the closing time of a d.c relay, because the diode is always back-biased, with its cathode tied to the positive terminal
/archives//html/Amps/2022-12/msg00037.html (11,676 bytes)

315. Re: [Amps] .01uf caps across diodes ? (score: 1)
Author: MU 4CX250B <4cx250b@miamioh.edu>
Date: Mon, 12 Dec 2022 18:11:36 -0800
Hi Bill, I remember that argument,too, but It doesnt carry much water with todays uniform components. The back resistance of a series string of diodes is so high that I doubt an uneven capacitive vol
/archives//html/Amps/2022-12/msg00041.html (11,562 bytes)

316. Re: [Amps] .01uf caps across diodes ? (score: 1)
Author: MU 4CX250B <4cx250b@miamioh.edu>
Date: Tue, 13 Dec 2022 09:21:02 -0800
An interesting point, Steve. If I understand you, youre saying that if a modern diode in a series string approaches reverse breakdown, it will start to conduct, thus shifting its overload voltage to
/archives//html/Amps/2022-12/msg00043.html (14,395 bytes)

317. Re: [Amps] Repairing early Alpha Amp pushbutton switches (score: 1)
Author: MU 4CX250B <4cx250b@miamioh.edu>
Date: Mon, 19 Dec 2022 12:00:44 -0800
Very interesting, Lon. Nice work! 73, Jim w8zr Sent from my iPhone _______________________________________________ Amps mailing list Amps@contesting.com http://lists.contesting.com/mailman/listinfo/a
/archives//html/Amps/2022-12/msg00086.html (9,197 bytes)

318. Re: [Amps] What to do about 'Neutral' in HB amp? (score: 1)
Author: MU 4CX250B <4cx250b@miamioh.edu>
Date: Wed, 28 Dec 2022 21:04:32 -0800
Paul, I dont understand this. The blower surely isnt in series with HV primary. How could that work? 73, Jim w8zr Sent from my iPhone _______________________________________________ Amps mailing list
/archives//html/Amps/2022-12/msg00150.html (10,993 bytes)

319. Re: [Amps] What to do about 'Neutral' in HB amp? (score: 1)
Author: MU 4CX250B <4cx250b@miamioh.edu>
Date: Thu, 29 Dec 2022 05:35:54 -0800
Ahh, yes, now I remember that circuit. I was under the impression that blower speed was relatively insensitive to voltage for an induction motor, with the reduced voltage mostly affecting the back pr
/archives//html/Amps/2022-12/msg00154.html (11,215 bytes)

320. [Amps] World's worst coax connectors (score: 1)
Author: Jim Garland <4cx250b@miamioh.edu>
Date: Thu, 20 Apr 2023 11:27:56 -0600
As you probably know, the  famous Art of Electronics, by Paul Horowitz (W1HFA) and Winfield Hill, is the comprehensive go-to bible for hams and other electronics devotees. Published by Cambridge Univ
/archives//html/Amps/2023-04/msg00027.html (8,464 bytes)

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