04-07-2017, 10:11 AM
Apologies for my lack of precision in post #29, Mark. I admit to not always making notes of voltage readingss, power outputs, and other data. Back when I did the test mentioned in post #29, I simply wanted to se how the amp. performed with a sinewave signal at an approximately known level - i say approximately because my Audio Generator doesn't have a calibrated fine level control. The 'corase control can be switched to give maximum o/ps of 20, 200, & 2000mV respectively, whilst the 'fine' control ( a liniear pot.) varies that, and, at half max. setting on the 200mV range, approx. 100mV is produvced. Going back to the record player, I haven't noted the gain figures between the two valves, either, being content to know that the replacemnet one provides good quality sound at all settings of the player's controls, whilst the first one distorts after ca. 20 minutes, no doubt due to Heater-Cathode leakage. After over 44 years in the repair business I don't write up everything the way I did back in the 60s & 70s!
