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Question about set amps and low sensitivity spkrs

Hi, In about 3 weeks I will take ownership of an 18wpc SET integrated. I currently run an Arcam SS amp with B&W 602 S2 speakers and I'm still undecided about new speakers (more sensitive, tube friendly) to mate with my new amp. My question is, can I run my current 90db sensitive B&W speakers with the SET integrated without doing damage, or shortening the life of my new tubes? I'd hate to have the amp sitting in a box waiting for me to decide on new speakers :) I frequently see that B&W speakers don't mate well with tubes...why is this?
thanks
Michael
mbleming
newbee
4,093 posts
 
FWIW most tube amps put out the same wattage at 4 & 8 ohms. It neither doubles nor halves. 18w at 8 ohms is going to be 18w at 4 ohms.
tvad
9,467 posts
 
Well, there you go.
mbleming OP
33 posts
 
Thanks again guys, very much appreciated. As far as speakers go, I have been giving serious thought to the Devore Gibbons, but I'm still not sure. Thanks again!
tvad
9,467 posts
 
The problem is, if you have speakers that have large impedance dips, and you have an amp that feeds the same power into the different impedance loads, then you end up with unbalanced sound as the frequencies at the lower impedances will have less volume.

Therefore, those speakers require power that doubles into the lower impedances for balanced sound.

That's why tube amps work better with speakers with flat impedance curves.
pubul57
3,712 posts
 
Newbee, I agree that a tube amp generally puts out the same power into different impedance loads of the speaker, but I'm talking about the output taps (4ohm, 8ohm etc.) of the amplifier. I thought that into the same loads, the 4ohm tap and the 8 ohm taps put out different power. That was my understanding with the Music Reference gear (I think he said a 3db drop using the 4ohm tap into a 8ohm load versus the 8 ohm tap); but I could be wrong.
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