In Reply to: WTF ???? posted by vinnie2 on August 15, 2016 at 04:06:51:
"With 50 per you should not even have to worry about the sensitivity of your speakers."Vinnie, there are quite a few "Watt Hog" speakers out there, for which 50 WPC would prove insufficient.
Paul Joppa's 102 dB. rule is useful in matching amps to speakers. "Joppa's Rule" states that for "average" volume listening spaces, an amp/speaker combo should be capable of 102 dB. SPL peaks at a 1 M. distance.
Where things can become highly problematic is the derating sometimes necessary when commercial speakers are mated to tube power amps. A nominally 4 ohm speaker whose claimed sensitivity for 2.83 V of drive is 89 dB. is "really" 86 dB. sensitive, as 2.83 V. into 4 ohms is 2 W., not 1 W. Another "gotcha" is impedance curve. Large dips in the curve, particularly in the deep bass, require reducing the nominal impedance and allowing for the consequent reduced sensitivity.
Big Thiel speakers, with their dips down to 1 ohm, are (IMO) very poor candidates for mating to tube amps. The power O/P needed is less important than a very large damping factor. BTW, those big Thiels will wreck mass market SS equipment, should it be connected up.
Eli D.
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Follow Ups
- RE: WTF ???? - Eli Duttman 08/15/1613:27:12 08/15/16 (1)
- RE: 102dB peaks???? - BigguyinATL 06:36:08 08/30/16 (0)