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Total 419 documents matching your query.

121. Re: [Amps] Direct rectification of AC mains to derive the amp, VDD, supply (score: 1)
Author: Manfred Mornhinweg <manfred@ludens.cl>
Date: Thu, 19 Sep 2013 15:37:44 +0000
Roger, the near electrocution you describe was due to several concurrent problems: The short circuit due to a poor solder job, lack of a ground fault interrupter, and poor grounding of the equipment.
/archives//html/Amps/2013-09/msg00235.html (8,026 bytes)

122. Re: [Amps] MRFE6VP61K25HR6 (score: 1)
Author: Manfred Mornhinweg <manfred@ludens.cl>
Date: Thu, 19 Sep 2013 15:59:15 +0000
David, and all, It can do quite some more than that, but for true 1kW PEP SSB, with speech processing, the thermal issues are difficult to handle. An amp using the board mentioned will likely not be
/archives//html/Amps/2013-09/msg00236.html (10,905 bytes)

123. Re: [Amps] Re Direct rectification of AC mains to derive the amp, VDD, supply (score: 1)
Author: Manfred Mornhinweg <manfred@ludens.cl>
Date: Fri, 20 Sep 2013 15:56:19 +0000
Standards, oh standards! I will try to explain the clearest way I can how the power distribution system in Chile is configured. The same or almost the same is used in most other countries that have 2
/archives//html/Amps/2013-09/msg00267.html (15,588 bytes)

124. Re: [Amps] Direct rectification of AC mains to derive the amp, VDD supply (score: 1)
Author: Manfred Mornhinweg <manfred@ludens.cl>
Date: Sun, 22 Sep 2013 13:15:45 +0000
Bill, As someone once pointed out, standards are great! That's why there are so many of them. :-) I prefer to express that a little bit pointier: The best thing about standards is that there are so m
/archives//html/Amps/2013-09/msg00278.html (7,595 bytes)

125. Re: [Amps] Direct rectification of AC mains to drive the amp, VDD Supply (score: 1)
Author: Manfred Mornhinweg <manfred@ludens.cl>
Date: Mon, 23 Sep 2013 16:07:13 +0000
Dear all, it's funny to see how so many people discuss this matter, with some of them bringing up good technical reasons in favor or against, and others just giving their opinion without any good sup
/archives//html/Amps/2013-09/msg00287.html (13,944 bytes)

126. Re: [Amps] Direct rectification of AC mains to drive the amp, (score: 1)
Author: Manfred Mornhinweg <manfred@ludens.cl>
Date: Tue, 24 Sep 2013 15:22:07 +0000
big C filter ??? I have done that. The result depends a lot on the impedance of the power grid! Assuming that the grid has a negligible impedance, which is usually the case when we are considering v
/archives//html/Amps/2013-09/msg00292.html (12,051 bytes)

127. Re: [Amps] Direct rectification of AC mains to drive the amp, VDD Supply (score: 1)
Author: Manfred Mornhinweg <manfred@ludens.cl>
Date: Wed, 25 Sep 2013 13:23:04 +0000
Bill, Hi Manfred: If this hotspotting problem occurs, say when doing RTTY at a high power level, how quickly does it happen? I frankly don't know for sure, as I haven't seen it happening yet. But sin
/archives//html/Amps/2013-09/msg00302.html (11,478 bytes)

128. Re: [Amps] Direct rectification of AC mains to drive the amp, VDD, Supply (score: 1)
Author: Manfred Mornhinweg <manfred@ludens.cl>
Date: Thu, 26 Sep 2013 17:36:14 +0000
Bill, There is a better way if you have a dual-channel scope. Use both channels in ADD mode and set one of them to INVERT and DO NOT connect the probe ground to anything. That way both probes are "fl
/archives//html/Amps/2013-09/msg00307.html (10,261 bytes)

129. Re: [Amps] Other HV rectifier diodes (score: 1)
Author: Manfred Mornhinweg <manfred@ludens.cl>
Date: Thu, 26 Sep 2013 18:16:44 +0000
John, In addition to the high voltage diodes 6A10 mentioned earlier, rated for 1 kV PIV, 6A DC and 400 Amp surge, another useful part for high power is the M7P5 from Edal Industries. These are rated
/archives//html/Amps/2013-09/msg00308.html (9,021 bytes)

130. Re: [Amps] Other HV rectifier diodes (score: 1)
Author: Manfred Mornhinweg <manfred@ludens.cl>
Date: Thu, 26 Sep 2013 23:03:22 +0000
Lee, If you have a 1000 volt power supply, what should the diode stack voltage rating be? In principle, just a little more than those 1000V should be enough, as long as it's a bridge rectifier. That
/archives//html/Amps/2013-09/msg00311.html (12,731 bytes)

131. [Amps] Power factor (score: 1)
Author: Manfred Mornhinweg <manfred@ludens.cl>
Date: Fri, 27 Sep 2013 18:37:43 +0000
Jim, I will take you message as a cue to write another of mine, but it's addressed to everyone really, and specially to those who are not up to date with power conversion technology. Before some peop
/archives//html/Amps/2013-09/msg00316.html (14,628 bytes)

132. Re: [Amps] Direct rectification of AC mains to drive the amp, (score: 1)
Author: Manfred Mornhinweg <manfred@ludens.cl>
Date: Sat, 28 Sep 2013 17:32:39 +0000
Bill, Power factor correction is an area I am a bit hazy on. Could someone explain why the power factor would be different between a direct-rectified PS and a transformer-isolated one? I have mention
/archives//html/Amps/2013-09/msg00320.html (8,741 bytes)

133. Re: [Amps] Direct rectification of AC mains to power the amp, VDD Supply (score: 1)
Author: Manfred Mornhinweg <manfred@ludens.cl>
Date: Sat, 28 Sep 2013 17:46:59 +0000
Leigh, ...or rather than conjecture one could simply ask the savvy RF application engineers at Microsemi whose role and raison d'?tre it is to ensure their MOSFET RF power products are properly and o
/archives//html/Amps/2013-09/msg00321.html (9,008 bytes)

134. Re: [Amps] Direct rectification of AC mains to drive the amp, VDD Supply (score: 1)
Author: Manfred Mornhinweg <manfred@ludens.cl>
Date: Sat, 28 Sep 2013 18:22:27 +0000
Bill, That's doing it the hard way. Just set the scope input to AC instead of DC. Problem solved. I wish it were that easy. But it isn't. For example, let's consider this case: You want to check the
/archives//html/Amps/2013-09/msg00322.html (13,268 bytes)

135. Re: [Amps] Direct rectification of AC mains to drive the amp, (score: 1)
Author: Manfred Mornhinweg <manfred@ludens.cl>
Date: Mon, 30 Sep 2013 13:10:41 +0000
Alex, First of all, there is not so much of a difference between a transformer power supply and a PFC: the both are based on an inductive input element- a transformer primary here, and a series induc
/archives//html/Amps/2013-09/msg00337.html (10,219 bytes)

136. Re: [Amps] Direct rectification of AC mains to drive the amp, VDD Supply (score: 1)
Author: Manfred Mornhinweg <manfred@ludens.cl>
Date: Mon, 30 Sep 2013 13:26:40 +0000
Alex, I fully agree with you on this. I most often do it that way too. Even without the benefit of a rubber mat. But in this crazy world, where some people who mess up and hurt themselves look for ot
/archives//html/Amps/2013-09/msg00338.html (9,814 bytes)

137. Re: [Amps] Solid state or tubes for HPAs (score: 1)
Author: Manfred Mornhinweg <manfred@ludens.cl>
Date: Sat, 05 Oct 2013 14:24:42 +0000
John, The engineer from another institution who was next to me had made a compact 6 kW CW amp at 1.3 GHz using RFMD gallium nitride transistors, 63 % efficient,linear, 64 transistors, water cooled. Q
/archives//html/Amps/2013-10/msg00039.html (9,252 bytes)

138. Re: [Amps] Plate modulation from power supply ripple? (score: 1)
Author: Manfred Mornhinweg <manfred@ludens.cl>
Date: Sat, 05 Oct 2013 15:20:19 +0000
Hi all, let me add my way to see this ripple modulation matter: First, let's think tubes. In a tube, cathode current flow depends on the electric field around the cathode, which is created by the com
/archives//html/Amps/2013-10/msg00042.html (18,246 bytes)

139. Re: [Amps] 160M PI network Toroidal Coil (score: 1)
Author: Manfred Mornhinweg <manfred@ludens.cl>
Date: Sat, 05 Oct 2013 15:25:26 +0000
Paul, I'm going to convert a SB221 to a single band 160M amp. It seems most of the amps these days use a toroidal coil for the 160M Output PI network. Does anybody know what cores are typically used
/archives//html/Amps/2013-10/msg00044.html (8,059 bytes)

140. Re: [Amps] Direct rectification of AC mains to drive the amp, (score: 1)
Author: Manfred Mornhinweg <manfred@ludens.cl>
Date: Sat, 05 Oct 2013 15:37:09 +0000
Jim, Bill, and all, So, how about simply putting a small capacitor in each probe lead? Say about .001 uF or perhaps even smaller? Haven't actually tried this but it should isolate the DC enough, I'd
/archives//html/Amps/2013-10/msg00047.html (9,538 bytes)


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