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Audio and Video Talk
Valves / Vacuum Tubes
Armstrong A220 design questions
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<blockquote data-quote="Ampdog" data-source="post: 804134" data-attributes="member: 144"><p>One of those embarrassing moments where I should be honest and come clean. The figures are wrong - not sure what arithmetic I did that time of night :facepalm:</p><p></p><p>{<strong>For those interested</strong>, C1 acts in parallel with [R4 in parallel with the valve internal resistance rp = 65K average]. That gives about 50K, and the roll-over frequency with C1 (2200pF) will be about 1,5 KHz, not 320 Hz! Still rather low, but I will leave further design considertions be.}</p><p></p><p>My apology!</p></blockquote><p></p>
[QUOTE="Ampdog, post: 804134, member: 144"] One of those embarrassing moments where I should be honest and come clean. The figures are wrong - not sure what arithmetic I did that time of night :facepalm: {[b]For those interested[/b], C1 acts in parallel with [R4 in parallel with the valve internal resistance rp = 65K average]. That gives about 50K, and the roll-over frequency with C1 (2200pF) will be about 1,5 KHz, not 320 Hz! Still rather low, but I will leave further design considertions be.} My apology! [/QUOTE]
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Audio and Video Talk
Valves / Vacuum Tubes
Armstrong A220 design questions
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