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DIY For Audio
Radford STA25 HT current?
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<blockquote data-quote="fredeb" data-source="post: 981591" data-attributes="member: 13623"><p>If voltage is indeed ~415V at the EL34 anode , and each cathode resistor is 39 ohm , then you're reading ~2V across each 39 ohm resistor . Measure each cathode resistor to be sure that value hasn't drifted .</p><p></p><p>2V / 39 ohm = ~51mA</p><p></p><p>51mA x 415V = ~21W dissipation per tube ( approx. 84% of EL34 max dissipation of 25W ) . Not entirely accurate , but good enough to check . </p><p>To calculate accurately see here : <a href="https://robrobinette.com/Tube_Bias_Calculator.htm" target="_blank">https://robrobinette.com/Tube_Bias_Calculator.htm</a></p><p></p><p>Can you ascertain what correct voltage is at EL34 anode please (pin3) .</p><p></p><p><img src="https://www.premierguitar.com/ext/resources/images/content/2015_07/FEAT/Tubes-101/EL34-Tube-Diagram-WEB.jpg" alt="" class="fr-fic fr-dii fr-draggable " style="" /></p></blockquote><p></p>
[QUOTE="fredeb, post: 981591, member: 13623"] If voltage is indeed ~415V at the EL34 anode , and each cathode resistor is 39 ohm , then you're reading ~2V across each 39 ohm resistor . Measure each cathode resistor to be sure that value hasn't drifted . 2V / 39 ohm = ~51mA 51mA x 415V = ~21W dissipation per tube ( approx. 84% of EL34 max dissipation of 25W ) . Not entirely accurate , but good enough to check . To calculate accurately see here : [url=https://robrobinette.com/Tube_Bias_Calculator.htm]https://robrobinette.com/Tube_Bias_Calculator.htm[/url] Can you ascertain what correct voltage is at EL34 anode please (pin3) . [IMG]https://www.premierguitar.com/ext/resources/images/content/2015_07/FEAT/Tubes-101/EL34-Tube-Diagram-WEB.jpg[/IMG] [/QUOTE]
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Radford STA25 HT current?
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