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Tube DIY Asylum Do It Yourself (DIY) paradise for tube and SET project builders. |
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Tube DIY Asylum Do It Yourself (DIY) paradise for tube and SET project builders. |
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In Reply to: RE: No free lunch !!! posted by RioTubes on September 3, 2008 at 09:46:09:
Your measurement of 557 VDC for B+, from last year's notes, when the schematic is calling for 700 VDC, really makes it HARD for me personally to draw any solid conclusions.If you drop 60.4 VDC across a 900 ohm Mills MRA-12, you have a computed current (Ohms Law, I'll enclose a chart for you to keep handy) of 60.4 VDC divided by 900 ohms, or 0.06711 Amperes. Is it really a 900 ohm part? Percy stocks 825, 909, and 1,000 ohm Mills MRA-12s.
IF, (and we don't know or trust this) you have 340 VDC P-K, simply multiply the current by the voltage to get the plate's power dissipation. That is 22.81 watts, not enough to be melting solder out of tube pins.
Remeasure everything completely and meticulously. (Sound familiar Slownlo??). Put your meter's probes on the output tube's plate, at the tube socket, and ditto for the cathode, also at the tube socket. Be careful, lethal voltages exist.
Jeff Medwin
Edits: 09/03/08
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