KPA500 Curiosity Question
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Is there a published circuit diagram of the KPA500, in particular the power supply? I was curious about the design of the power supply and had a few questions. Note: these are motivated merely by my curiosity and interest. I have no real need to know.
For example, the KPA500 shows a block diagram of the amplifier & power supply and one of the voltage outputs is +270 and I was wondering what part of the amp circuit needs 270 volts, or 60 volts for that matter. In idle mode, the HV display on my KPA500 reads 71 volts. Thus, not 60 and not 270 volts. Another question -- the other voltages from the supply are +5, -12, and +12. I assume these are regulated voltages. But, is the +60 and +270 regulated? If these are regulated, what kind of voltage regulator is used. I am likely ignorant and even possibly naive in this area as I have only used low-voltage regulator chips and so do not even know if HV regulator chips even exist (would they be stacked devices?). End of questions for now. Yes, a circuit diagram would answer all my questions. 73, phil, K7PEH ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[hidden email] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to [hidden email] |
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Phil, I don't have a copy of the block diagram in front of me, but from what I witnessed the input ranges are up to the potential of 270 vac in. The output under load would be ~60vdc under load. What you are seeing in the block diagram appears to be misread, as the voltages are with the parameters of what I saw with my KPA500 when I owned one. Great amp.... hard to sell.
73, Bill K9YEQ -----Original Message----- From: [hidden email] <[hidden email]> On Behalf Of Phil Hystad Sent: Thursday, March 22, 2018 11:22 AM To: Elecraft <[hidden email]> Subject: [Elecraft] KPA500 Curiosity Question Is there a published circuit diagram of the KPA500, in particular the power supply? I was curious about the design of the power supply and had a few questions. Note: these are motivated merely by my curiosity and interest. I have no real need to know. For example, the KPA500 shows a block diagram of the amplifier & power supply and one of the voltage outputs is +270 and I was wondering what part of the amp circuit needs 270 volts, or 60 volts for that matter. In idle mode, the HV display on my KPA500 reads 71 volts. Thus, not 60 and not 270 volts. Another question -- the other voltages from the supply are +5, -12, and +12. I assume these are regulated voltages. But, is the +60 and +270 regulated? If these are regulated, what kind of voltage regulator is used. I am likely ignorant and even possibly naive in this area as I have only used low-voltage regulator chips and so do not even know if HV regulator chips even exist (would they be stacked devices?). End of questions for now. Yes, a circuit diagram would answer all my questions. 73, phil, K7PEH ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[hidden email] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to [hidden email] ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[hidden email] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to [hidden email] |
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In reply to this post by Phil Hystad-3
The 270 volts is bias for the pin diode switching. It’s generated with a voltage triplet off the 60 volt supply transformer.
Chuck KE9UW [hidden email] Sent from my iPad > On Mar 22, 2018, at 11:24 AM, Phil Hystad <[hidden email]> wrote: > > Is there a published circuit diagram of the KPA500, in particular the power supply? I was curious about the design of the power supply and had a few questions. Note: these are motivated merely by my curiosity and interest. I have no real need to know. > > For example, the KPA500 shows a block diagram of the amplifier & power supply and one of the voltage outputs is +270 and I was wondering what part of the amp circuit needs 270 volts, or 60 volts for that matter. > > In idle mode, the HV display on my KPA500 reads 71 volts. Thus, not 60 and not 270 volts. > > Another question -- the other voltages from the supply are +5, -12, and +12. I assume these are regulated voltages. But, is the +60 and +270 regulated? If these are regulated, what kind of voltage regulator is used. I am likely ignorant and even possibly naive in this area as I have only used low-voltage regulator chips and so do not even know if HV regulator chips even exist (would they be stacked devices?). > > End of questions for now. Yes, a circuit diagram would answer all my questions. > > 73, phil, K7PEH > > ______________________________________________________________ > Elecraft mailing list > Home: http://mailman.qth.net/mailman/listinfo/elecraft > Help: http://mailman.qth.net/mmfaq.htm > Post: mailto:[hidden email] > > This list hosted by: http://www.qsl.net > Please help support this email list: http://www.qsl.net/donate.html > Message delivered to [hidden email] Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[hidden email] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to [hidden email]
Chuck, KE9UW
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In reply to this post by Phil Hystad-3
Thanks to those who answered my questions. Quick response on ye olde electraft group.
73, phil > On Mar 22, 2018, at 9:22 AM, Phil Hystad <[hidden email]> wrote: > > Is there a published circuit diagram of the KPA500, in particular the power supply? I was curious about the design of the power supply and had a few questions. Note: these are motivated merely by my curiosity and interest. I have no real need to know. > > For example, the KPA500 shows a block diagram of the amplifier & power supply and one of the voltage outputs is +270 and I was wondering what part of the amp circuit needs 270 volts, or 60 volts for that matter. > > In idle mode, the HV display on my KPA500 reads 71 volts. Thus, not 60 and not 270 volts. > > Another question -- the other voltages from the supply are +5, -12, and +12. I assume these are regulated voltages. But, is the +60 and +270 regulated? If these are regulated, what kind of voltage regulator is used. I am likely ignorant and even possibly naive in this area as I have only used low-voltage regulator chips and so do not even know if HV regulator chips even exist (would they be stacked devices?). > > End of questions for now. Yes, a circuit diagram would answer all my questions. > > 73, phil, K7PEH > > ______________________________________________________________ > Elecraft mailing list > Home: http://mailman.qth.net/mailman/listinfo/elecraft > Help: http://mailman.qth.net/mmfaq.htm > Post: mailto:[hidden email] > > This list hosted by: http://www.qsl.net > Please help support this email list: http://www.qsl.net/donate.html > Message delivered to [hidden email] ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[hidden email] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to [hidden email] |
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