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Audio and Video Talk
Valves / Vacuum Tubes
Valve etiquette and care
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<blockquote data-quote="Ampdog" data-source="post: 507169" data-attributes="member: 144"><p>When one googles the phenomenon of cathode stripping, it would appear to only apply to valve voltages of >1 KV on the anode. Some cathode 'flakes' might very infrequently come off and land somewhere where visible. This has nothing to do with cathode stripping. As mentioned in several sources, rectifier valves if anything should be prone to cathode stripping if such existed, considering the high potential gradient between cathode and anode at every swich-on and before cathode warm-up. Most last many years without any loss of emission.</p><p></p><p>I would be more concerned with moisture getting into the inside of the base when washing valves. The glass-to-base seal is not always perfectly intact. Moreover, many of the newer octal based power valves have no seal between base and glass. The glass envelope is held in place by the short solid electrode leads soldered into the base pins. Also, older base pins can be found where the seam down a rolled pin (a tube) is not sealed, and moisture might also possibly get inside thataway. With regularly operating valves such would evaporate relatively quickly, but when storing washed valves for long periods oxidation is a possibility.</p></blockquote><p></p>
[QUOTE="Ampdog, post: 507169, member: 144"] When one googles the phenomenon of cathode stripping, it would appear to only apply to valve voltages of >1 KV on the anode. Some cathode 'flakes' might very infrequently come off and land somewhere where visible. This has nothing to do with cathode stripping. As mentioned in several sources, rectifier valves if anything should be prone to cathode stripping if such existed, considering the high potential gradient between cathode and anode at every swich-on and before cathode warm-up. Most last many years without any loss of emission. I would be more concerned with moisture getting into the inside of the base when washing valves. The glass-to-base seal is not always perfectly intact. Moreover, many of the newer octal based power valves have no seal between base and glass. The glass envelope is held in place by the short solid electrode leads soldered into the base pins. Also, older base pins can be found where the seam down a rolled pin (a tube) is not sealed, and moisture might also possibly get inside thataway. With regularly operating valves such would evaporate relatively quickly, but when storing washed valves for long periods oxidation is a possibility. [/QUOTE]
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Audio and Video Talk
Valves / Vacuum Tubes
Valve etiquette and care
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