RE: WTF ????

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RE: WTF ????

Posted by Eli Duttman (A) on August 15, 2016 at 13:27:12

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 Full Thread

Topic - For a mere 7700 dollars you can have some Magnavox amps. - Michael Samra 22:17:02 08/14/16 (12)

RE: For a mere 7700 dollars you can have some Magnavox amps. - Sherwood Forest 15:10:28 08/30/16 (0)

RE: For a mere 7700 dollars you can have some Magnavox amps. - BillH 06:55:41 08/16/16 (1)

RE: For a mere 7700 dollars you can have some Magnavox amps. - mark.korda@myfairpoint.net 15:58:03 08/16/16 (0)

RE: For a mere 7700 dollars you can have some Magnavox amps. - airtime 07:24:19 08/15/16 (4)

RE: For a mere 7700 dollars you can have some Magnavox amps. - Tom Bavis 05:52:07 08/17/16 (0)

RE: For a mere 7700 dollars you can have some Magnavox amps. - Michael Samra 11:35:03 08/15/16 (2)

RE: For a mere 7700 dollars you can have some Magnavox amps. - airtime 12:45:57 08/15/16 (1)

RE: For a mere 7700 dollars you can have some Magnavox amps. - Michael Samra 23:38:21 08/15/16 (0)

"Sounds better..." - briggs 07:10:44 08/15/16 (0)

WTF ???? - vinnie2 04:06:51 08/15/16 (2)

RE: WTF ???? - Eli Duttman 08/15/1613:27:12 08/15/16 (1)

RE: 102dB peaks???? - BigguyinATL 06:36:08 08/30/16 (0)

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)

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