Reply to thread

Message

<blockquote data-quote="n2audio" data-source="post: 4830835" data-attributes="member: 540940">It can, and probably does a lot of the time.Actually - with a class D amp I came up with something closer to 10A.Those were my guesstimations for equivalent continuous current draw for an amp playing music.How did I arrive at those numbers??Assumed - class D efficiency at full volume = 75%- class A/B efficiency at full volume = 60%- Voltage = 14vClass D at full volume reqires (500/.75) 666.7w --- 666.7/14 = 47.6AClass A/B at full volume requires (500/.6) = 833.3w --- 833.3/14 = 59.5AThat is approximately what would be required playing sine waves at full volume.MUSIC on the other hand requires substantially less power.&nbsp; The statistic I go with came from Carsound -- I believe it was stated that most commercially available music has a crest factor between 10% and 25%, and anything over about 33% could hardly be recognizable as music -- so I just divide maximum current by 3 to get an idea of current demand for music at full volume.So with the class D you&#039;d have 15.6A and with the A/B it would be 19.8A.Now assuming the listener won&#039;t have it at full blast continuously -- ~10A and ~12-15A, respectively, seem like reasonable approximations to me.</blockquote>

[QUOTE="n2audio, post: 4830835, member: 540940"] It can, and probably does a lot of the time. Actually - with a class D amp I came up with something closer to 10A. Those were my guesstimations for equivalent continuous current draw for an amp playing music. How did I arrive at those numbers?? Assumed - class D efficiency at full volume = 75% - class A/B efficiency at full volume = 60% - Voltage = 14v Class D at full volume reqires (500/.75) 666.7w --- 666.7/14 = 47.6A Class A/B at full volume requires (500/.6) = 833.3w --- 833.3/14 = 59.5A That is approximately what would be required playing sine waves at full volume. MUSIC on the other hand requires substantially less power. The statistic I go with came from Carsound -- I believe it was stated that most commercially available music has a crest factor between 10% and 25%, and anything over about 33% could hardly be recognizable as music -- so I just divide maximum current by 3 to get an idea of current demand for music at full volume. So with the class D you'd have 15.6A and with the A/B it would be 19.8A. Now assuming the listener won't have it at full blast continuously -- ~10A and ~12-15A, respectively, seem like reasonable approximations to me. [/QUOTE]

Verification