Posted by
Bill K9YEQ on
Mar 22, 2018; 4:38pm
URL: http://elecraft.85.s1.nabble.com/KPA500-Curiosity-Question-tp7639508p7639509.html
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:
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[hidden email]> On Behalf Of Phil Hystad
Sent: Thursday, March 22, 2018 11:22 AM
To: Elecraft <
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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
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