03-06-2022, 03:27 PM
You'd need a rubbish smoothing cap for any difference in hum or "pops"
1) Selenium/metal sometimes have high leakage, which may destroy the smoothing cap before something burns out. Hum on a valve rectifier is ONLY possible with dried out, or needing reformed, smoothing cap.
2) Pops on rectifier also suggest (a) Overvoltage / noise spikes on mains and (b) Very high ESR smoothing caps.
3) I've never seen Russian valves or Chinese that visually look poorly made.
With correct HT and decent quality smoothing caps the make of valve rectifier is irrelevant. I've seen low emission caused by wear induced by excess HT current caused by leaky caps.
1) Selenium/metal sometimes have high leakage, which may destroy the smoothing cap before something burns out. Hum on a valve rectifier is ONLY possible with dried out, or needing reformed, smoothing cap.
2) Pops on rectifier also suggest (a) Overvoltage / noise spikes on mains and (b) Very high ESR smoothing caps.
3) I've never seen Russian valves or Chinese that visually look poorly made.
With correct HT and decent quality smoothing caps the make of valve rectifier is irrelevant. I've seen low emission caused by wear induced by excess HT current caused by leaky caps.
