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21. [AMPS] ?: Cooling (score: 1): Author: drkirkby@ntlworld.com (David Kirkby); Date: Sat, 07 Apr 2001 20:12:03 +0100; My guess (and I admit I have not tested it) is that such an arrangement would not provide sufficient cooling. It would probably be fine for the screen, but there is electrical isolation (and so therm; /archives//html/Amps/2001-04/msg00165.html (8,819 bytes)
22. [AMPS] [Fwd: Problem with 4CX250. Need help, please.] (score: 1): Author: drkirkby@ntlworld.com (David Kirkby); Date: Sun, 22 Apr 2001 08:31:35 +0100; I received the following email from Isaac Díaz <fs12742@autovia.com> about 4CX250s. It appears to me that he has a problem with instability, which I have pointed out, and that the amplified ne; /archives//html/Amps/2001-04/msg00463.html (11,008 bytes)
23. [AMPS] Tube X-Ray Emission (score: 1): Author: drkirkby@ntlworld.com (David Kirkby); Date: Fri, 02 Mar 2001 22:14:21 +0000; I'm not an expert, but believe that unless you are running at 20 kV or more (perhaps even quite a bit more), it will not be a problem. I once had this discussion with someone where I used to work, wh; /archives//html/Amps/2001-03/msg00028.html (7,466 bytes)
24. [AMPS] Creepy Amplifier (score: 1): Author: drkirkby@ntlworld.com (David Kirkby); Date: Tue, 20 Feb 2001 13:03:27 +0000; How much higher are we taling about - 1%, 10% 100% or whatever ? One possibility (I admit remote) is that the current is not actually increasing, but instead the meters shunts have got hot and theref; /archives//html/Amps/2001-02/msg00262.html (8,961 bytes)
25. [AMPS] k2riw 2m amp! (score: 1): Author: drkirkby@ntlworld.com (David Kirkby); Date: Sat, 24 Feb 2001 22:46:54 +0000; Unless there is obscure amplifier design by K2RIW for 2m which I don't know of, the normal K2RIW is for 70 cm, not 2 m. The 4CX250B is rated for 300 W up to 175 MHz, if memory servers me correct. 200; /archives//html/Amps/2001-02/msg00320.html (8,488 bytes)
26. [AMPS] k2riw 2m amp! (score: 1): Author: drkirkby@ntlworld.com (David Kirkby); Date: Sat, 24 Feb 2001 23:24:46 +0000; I perhaps did not make it clear that each tube should produce around 300 W in class AB1 - ie 600 W for a two tube amp. In class C each tube produces around 380 W if memory serves me correct. Obviousl; /archives//html/Amps/2001-02/msg00321.html (8,205 bytes)
27. [AMPS] K2RIW Amps (score: 1): Author: drkirkby@ntlworld.com (David Kirkby); Date: Sun, 25 Feb 2001 20:20:30 +0000; I think in these arguments (anf it seems to have developed into that), it is essential to define what 'good' is. It's a bit pointless saying 900 W at good linearity, without defining what 'good' is.; /archives//html/Amps/2001-02/msg00334.html (9,051 bytes)
28. [AMPS] K2RIW Amps (score: 1): Author: drkirkby@ntlworld.com (David Kirkby); Date: Sun, 25 Feb 2001 23:02:19 +0000; But Rick did say 'good linearity' not 'good power'. He defined the power (900 W), but it was the linearity to which a rather subjective measure (excuse the pun) 'good' was used. I'm trying to make th; /archives//html/Amps/2001-02/msg00336.html (9,572 bytes)
29. [AMPS] HV PSU Question (score: 1): Author: drkirkby@ntlworld.com (David Kirkby); Date: Mon, 01 Jan 2001 23:16:27 +0000; You need to use a full wave rectification. Take the centre to earth and put each end of the transformer on the anodes of two high-voltage diodes. Join the cathodes together, to make the +Ve output. T; /archives//html/Amps/2001-01/msg00023.html (10,030 bytes)
30. [AMPS] HV PSU Question (score: 1): Author: drkirkby@ntlworld.com (David Kirkby); Date: Tue, 02 Jan 2001 00:06:46 +0000; I had a similar problem once. We needed a large HT transformer for a pair of 4CX1000As, and I managed to find one of 2.3 kV, 4.5 A in a skip. A company near by where I worked had gone bust and all th; /archives//html/Amps/2001-01/msg00025.html (9,792 bytes)
31. [AMPS] Thyratron crowbared HT power supplies. (score: 1): Author: drkirkby@ntlworld.com (David Kirkby); Date: Tue, 02 Jan 2001 13:35:24 +0000; Has anyone any experience of designing HT power supplies that crowbar in the event of an arc to protect the tube ? I've an EEV FX2519A hydrogen thyratron I'd like to use as detailed in fig 2 of http:; /archives//html/Amps/2001-01/msg00039.html (7,731 bytes)
32. [AMPS] Panel meters (score: 1): Author: drkirkby@ntlworld.com (David Kirkby); Date: Tue, 02 Jan 2001 17:12:36 +0000; I would have thought you have been quite lucky to get all those meters matching. In contrast, buying 9 x 1 mA meters and making your own shunts and multipliers should not be too difficult. The value; /archives//html/Amps/2001-01/msg00049.html (9,209 bytes)
33. [AMPS] 3 phase HT power supplies. (score: 1): Author: drkirkby@ntlworld.com (David Kirkby); Date: Sat, 06 Jan 2001 12:04:12 +0000; Hi, I'm looking to design an HT power supply for a YC156 (3CPX5000A7) triode. One approach is the common single phase input, single phase transformer, lots of expensive high voltage capacitors. I've; /archives//html/Amps/2001-01/msg00201.html (8,745 bytes)
34. [AMPS] Eimac - Care and Feeding of Power Grid Tubes (score: 1): Author: drkirkby@ntlworld.com (David Kirkby); Date: Mon, 08 Jan 2001 23:24:21 +0000; Hi, Someone is regularly selling CD's on eBay with some potentially useful information: http://cgi.ebay.com/aw-cgi/eBayISAPI.dll?ViewItem&item=535115318&ed=978660813 I bought that one for $10.95, as; /archives//html/Amps/2001-01/msg00293.html (10,683 bytes)
35. [AMPS] Two XFMR in parallel (score: 1): Author: drkirkby@ntlworld.com (David Kirkby); Date: Wed, 17 Jan 2001 14:15:21 +0000; I have not done this, but would guess that while you might be able to increase the output beyond 0.6 A, you won't get 1 A - there is nothing to force the currents to split in the right ratio. (60% fr; /archives//html/Amps/2001-01/msg00413.html (11,253 bytes)
36. [AMPS] receivers (score: 1): Author: drkirkby@ntlworld.com (David Kirkby); Date: Thu, 18 Jan 2001 09:32:50 +0000; It would seem that paralleling high voltage transformers of slightly different voltages does quite a good job of that !! -- Dr. David Kirkby Ph.D, email: drkirkby@ntlwold.com (formally davek@medphys.; /archives//html/Amps/2001-01/msg00455.html (8,093 bytes)
37. [AMPS] Re: AC Mains in Europe (score: 1): Author: drkirkby@ntlworld.com (David Kirkby); Date: Thu, 18 Jan 2001 17:27:20 +0000; There are 3 wires - live neutral and earth. Neutral and earth are joined at the substation, so there at least there is 0 V between them. By the time it reaches your house, there can be a small voltag; /archives//html/Amps/2001-01/msg00467.html (8,365 bytes)
38. [AMPS] Re: Two XFMRs Parallel... (score: 1): Author: drkirkby@ntlworld.com (David Kirkby); Date: Thu, 18 Jan 2001 17:48:03 +0000; That is very interesting and something I for one overlooked. Given you have reactance in the windings, the phase could well be load dependant. i.e. whatever phase difference occurs off load, is not t; /archives//html/Amps/2001-01/msg00469.html (9,160 bytes)
39. [AMPS] Re: Two XFMRs Parallel... (score: 1): Author: drkirkby@ntlworld.com (David Kirkby); Date: Thu, 18 Jan 2001 17:54:24 +0000; I should have added that if the DC is paralleled after the rectifies, this phase difference could work to your advantage. If the two are out of phase, the caps will tend to get charged more often, r; /archives//html/Amps/2001-01/msg00470.html (8,873 bytes)
40. [AMPS] Re: Two XFMRs Parallel... (score: 1): Author: drkirkby@ntlworld.com (David Kirkby); Date: Fri, 19 Jan 2001 08:18:31 +0000; Sorry, but I don't agree with that statement either Tom. Why do you think 3-phase rectification has lower ripple than single phase ? If one bridge is starting to provide less voltage to the caps, as; /archives//html/Amps/2001-01/msg00488.html (9,751 bytes)

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