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1. [Amps] Need loading cap, plate transformer, doorknobs (score: 1): Author: jkearman@att.net (Jim Kearman); Date: Thu, 10 Nov 2005 13:43:30 +0000; 1. Need a ~900 pF air variable suitable for 1500-W amp. Must be less than 9" long behind the panel. I have a nice EF Johnson 153-32-4 but too long for my cabinet. 2. Need a 2500-3300 pF doorknob for; /archives//html/Amps/2005-11/msg00125.html (6,967 bytes)
2. [Amps] Svetlana SK1A socket cathode connection (score: 1): Author: jkearman@att.net (Jim Kearman); Date: Thu, 10 Nov 2005 22:28:52 +0000; Is the cathode connection in a Svetlana SK1A socket (GU74B/4CX800A) tied to the base or floating? Thanks. 73, Jim, KR1S _______________________________________________ Amps mailing list Amps@contesti; /archives//html/Amps/2005-11/msg00129.html (6,567 bytes)
3. [Amps] Emron rip-off (score: 1): Author: jkearman@att.net (Jim Kearman); Date: Fri, 11 Nov 2005 13:03:20 +0000; Compare the Emron text here http://emtron.com.au/amplifiers_dx1b.php to this http://www.therfshop.com/omega.htm Rudi at Emron tells me they have no connection with this guy, he's just ripping off the; /archives//html/Amps/2005-11/msg00140.html (6,485 bytes)
4. Re: [Amps] L4 power supply problem? (score: 1): Author: jkearman@att.net (Jim Kearman); Date: Mon, 14 Nov 2005 13:41:16 +0000; I used CDE 381LX electrolytics. Rated at 105 deg C, high-ripple, small. I recapped an SB-230 by making a Lucite plate to go over the holes where the originals were mounted, boring holes in it, and e; /archives//html/Amps/2005-11/msg00176.html (8,224 bytes)
5. [Amps] Aluminum alloys for panels? (score: 1): Author: jkearman@att.net (Jim Kearman); Date: Tue, 15 Nov 2005 04:47:11 +0000; I need to make two panels and a baseplate for an amp. I could cut down 19" panels but would like to find a cheaper way. Does anyone know what alloy of aluminum is used for rack panels? I was thinking; /archives//html/Amps/2005-11/msg00183.html (6,974 bytes)
6. Re: [Amps] Question about safety ground connection (score: 1): Author: jkearman@att.net (Jim Kearman); Date: Wed, 16 Nov 2005 11:19:29 +0000; Geez, talk about parasitics. 73, Jim, KR1S _______________________________________________ Amps mailing list Amps@contesting.com http://lists.contesting.com/mailman/listinfo/amps; /archives//html/Amps/2005-11/msg00232.html (8,558 bytes)
7. [Amps] Ac oil-filled caps on dc (score: 1): Author: jkearman@att.net (Jim Kearman); Date: Sat, 19 Nov 2005 15:56:33 +0000; I have a line on some 100-uF, 370-Vac Sprague oil-filled caps, new. I've read that ac oil-filled caps can be used at dc voltages of 3X the ac rating. So it looks like four of these in series would gi; /archives//html/Amps/2005-11/msg00341.html (6,612 bytes)
8. Re: [Amps] 3CPX800A7 Not Available (HAROLD B MANDEL) (score: 1): Author: jkearman@att.net (Jim Kearman); Date: Tue, 29 Nov 2005 20:14:26 +0000; The P version has the same external dimensions but taller ceramic structure internally, so it can withstand higher anode voltage. Eimac recommends 2250 max for the 3CX, and 3500 max for the 3CPX. For; /archives//html/Amps/2005-11/msg00517.html (7,781 bytes)
9. Re: [Amps] viable HV PS electrolytics (score: 1): Author: jkearman@att.net (Jim Kearman); Date: Wed, 07 Dec 2005 18:17:57 +0000; I think his price is too high, considering you have to buy 200 pieces. Try BG Micro http://www.bgmicro.com/ They have 330- and 470-uF _400 V_ electrolytics in single lots for the same price. I just b; /archives//html/Amps/2005-12/msg00070.html (7,277 bytes)
10. Re: [Amps] Emailing: hf_millinium (score: 1): Author: jkearman@att.net (Jim Kearman); Date: Mon, 12 Dec 2005 13:23:13 +0000; "Millinium"? "Refleced power"? "Price: Contact us"? "Time of delivery: Contact us"? "Better amplifiers through Photoshop." : ) 73, Jim, KR1S _______________________________________________ Amps maili; /archives//html/Amps/2005-12/msg00133.html (6,880 bytes)
11. Re: [Amps] 2KW $1000 amp kit (score: 1): Author: jkearman@att.net (Jim Kearman); Date: Mon, 02 Jan 2006 22:22:07 +0000; My Elmer, K2IHO (SK) told me to expect to pay $1 a watt, back in 1963. So $3 a watt doesn't seem so bad today. Oh, yeah, they'd be lining up for that one. But I don't think it's possible. The tube(s; /archives//html/Amps/2006-01/msg00105.html (8,313 bytes)
12. [Amps] Plate choke and bypassing (score: 1): Author: jkearman@att.net (Jim Kearman); Date: Fri, 06 Jan 2006 19:10:03 +0000; The last time I built an amp I just stuck in an available R-175 choke. This time I'd like to roll my own. The amp will use a pair of 4CX800As to develop 1500 W with Ep about 2500 under load. It will; /archives//html/Amps/2006-01/msg00224.html (7,379 bytes)
13. Re: [Amps] Westinghouse BC Ammeter QX-37 (score: 1): Author: jkearman@att.net (Jim Kearman); Date: Sun, 08 Jan 2006 16:31:41 +0000; You shouldn't be connecting it in the plate lead. Measure the cathode current, which is at low voltage. What's the resistance measured across the terminals? If it's a 2-A meter it should be pretty lo; /archives//html/Amps/2006-01/msg00253.html (7,833 bytes)
14. [Amps] Effects of load Z mismatch? (score: 1): Author: jkearman@att.net (Jim Kearman); Date: Mon, 09 Jan 2006 16:51:05 +0000; I'm aware that properly matching the tube to the pi network results in best efficiency and, presumably, less distortion. But to what extent? Let's say the correct ZL is 1500 ohms, and your pi net act; /archives//html/Amps/2006-01/msg00275.html (6,616 bytes)
15. Re: [Amps] Effects of load Z mismatch? (score: 1): Author: jkearman@att.net (Jim Kearman); Date: Mon, 09 Jan 2006 19:55:15 +0000; Frank Carcia gave me the insight I needed. As I'm using tetrodes I have been wrestling with k in ZL = Ep / k * Ip So I got numbers between 1460 and 1820 ohms. Thanks to the insight, I ran the number; /archives//html/Amps/2006-01/msg00299.html (8,027 bytes)
16. Re: [Amps] Effects of load Z mismatch? (score: 1): Author: jkearman@att.net (Jim Kearman); Date: Mon, 09 Jan 2006 20:56:47 +0000; Thanks. If I understand correctly, loading more heavily presents a lower impedance to the anode(s), and also incidentally reduces network Q. As a CW op, my main concern is efficiency and minimizing; /archives//html/Amps/2006-01/msg00301.html (8,044 bytes)
17. Re: [Amps] Burn-in for Eimac? (score: 1): Author: jkearman@att.net (Jim Kearman); Date: Mon, 16 Jan 2006 00:47:32 +0000; Bill, http://www.cpii.com/eimac/eiapps.htm Download AB21 - Conditioning of Large Radio-Frequency Power Tubes. It's a 700-kB PDF. 73, Jim, KR1S http://kr1s.kearman.com/ _______________________________; /archives//html/Amps/2006-01/msg00400.html (6,897 bytes)
18. [Amps] Copper / Brass strap? (score: 1): Author: jkearman@att.net (Jim Kearman); Date: Tue, 24 Jan 2006 23:19:21 +0000; I'm going to need to make connections between a 2-section bandswitch and the coil, padding caps and tuning/loading caps in a legal-limit HF amplifier. I'm looking at copper and brass sheet. I've neve; /archives//html/Amps/2006-01/msg00591.html (6,763 bytes)
19. Re: [Amps] What blower? (score: 1): Author: jkearman@att.net (Jim Kearman); Date: Fri, 27 Jan 2006 21:23:12 +0000; Their price is $61.14. Grainger.com has the same blower for $49.30. http://www.grainger.com/Grainger/wwg/productIndex.shtml and search for the part #. Note that at 0.500" static pressure this blower; /archives//html/Amps/2006-01/msg00628.html (7,137 bytes)
20. [Amps] Pi vs Pi-L (score: 1): Author: jkearman@att.net (Jim Kearman); Date: Wed, 01 Feb 2006 17:15:53 +0000; My understanding of current FCC regs is * the mean power of any spurious emission from HF transmitters or external RF power amplifiers installed after January 1, 2003, must be at least 43 dB below th; /archives//html/Amps/2006-02/msg00004.html (7,819 bytes)

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