In Reply to: Correction on Minimum Ripple posted by drlowmu on June 9, 2015 at 16:51:08:
Most meters read rms. 155-180mVrms is 438-509mVp-p, so PSUD was pretty close. PSUD shows an rms value at the far right of the data section. If you did not include the primary DCR adjusted by turns ratio squared when simulating the power transformer, that might cover the rest of the difference.
155-180mV at the finals, assuming a 20:1 turns ratio in the OPT and allowing for the tube's rp, still leaves 5-7mV hum in the output, which I (and a noticeable portion of Bottlehead's customers) find excessive if the speakers are more than around 98dB/w/m efficiency. But many with lower-efficiency speakers are not bothered by it at all. Hum is fortunately not correlated with signal envelope fluctuations so, like vinyl surface noise, it is easier to ignore than some seemingly more subtle issues.
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Follow Ups
- RE: Correction on Minimum Ripple - Paul Joppa 18:35:17 06/09/15 (4)
- RE: Correction on Minimum Ripple - Frihed89 02:00:49 06/10/15 (2)
- Yes indeed ... - Paul Joppa 13:19:15 06/10/15 (0)
- RE: Correction on Minimum Ripple - deathtube 667 05:27:32 06/10/15 (0)
- RE: Correction on Minimum Ripple - drlowmu 20:12:27 06/09/15 (0)