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Old 19th Apr 2018, 10:41 am   #21
Herald1360
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Join Date: Feb 2007
Location: Leominster, Herefordshire, UK.
Posts: 16,535
Default Re: Amplifier problem (record player)

Quote:
Originally Posted by Boom View Post
Ra is 230k for UL84 but Valve Museum doesn't give RA for UCL83. I got away with it for years though modding mates record players as they never were very loud until I upgraded/bodged them with a UCL83. I think that there is a couple of volts heater difference between the two valves also.
Ra is pretty much irrelevant here, RL is the useful value. (Though the datasheets are sometimes a bit vague about which is which!)

UL84 about 2.5k, UCL83 about 5k for ideal load. In practice, just using 2.5k on a UCL83 won't make a vast difference. UCL82 also about 5k but would give more grunt than the UCL83.
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