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It still sounds like audio expansion to me, surely the enemy of sustain? As the note decayed, the positive dc would decline too, decreasing gain and steepening the decay curve.
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Kevin O'Connor mentioned in one of his books that the old wax and paper caps rolled off the highs. Anyone experienced this?WARNING! Musical Instrument amplifiers contain lethal voltages and can retain them even when unplugged. Refer service to qualified personnel.
REMEMBER: Everybody knows that smokin' ain't allowed in school !Comment
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Alex, to answer your question, the grounded cathodes are part of what we call grid leak bias. Some old Fender inoput stages are the same way. Normally I'd expect larger grid resistors than 1meg. Like maybe 4.7meg maybe. Look up grid leak bias.
The cathode emits electrons just because it is hot. They form a cloud around the cathode called the space charge. These elctrons will accumulate on the nearby grid, giving it a net negative charge. Compared to the zero volts of the cathode, then the tube is biased.
Compare that to the more common method of putting a positive voltage on the cathode by way of current through the cathode resistor causing a voltage drop.Education is what you're left with after you have forgotten what you have learned.Comment
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Thanks - I get it, seen that before but yes, with bigger resistors. Couldn't really ask for a more succinct explanation... Those 1 megs looked like ground references and I couldn't see past that.Comment
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They are that too, of course.
Like a piece of beef is both animal tissue and part of my dinner.
No, I don't really know what that means either...Education is what you're left with after you have forgotten what you have learned.Comment
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