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Tube amps and speaker ohms

In your opinion , do push pull amps work better with 8 ohms or 4 ohms. .I am under the impression the lower the ohms, the more power is demanded from the amp....Another question, are there low powered SET amps ,and high power SET amps?
I'm looking at a 40 watt 845 tube amp for my 8 ohm, 89 db speaker.. just cked the Thor has a 86 db W18 midwoofers(2 per cabinet) and a 88 db tweeter. Will an 845 amp rated 40 watts be able to drive the 86/88 db speaker? With authority, bass, mids, highs, in dynamic sound stage? Synergy? Or poor match?
bartokfan
eagleman6722
217 posts
 
Ok, here is a question that may show my ignorance of this subject but, I will ask anyway. I have a TAD-60 AMP (60 WPC ultralinear).. It has 8 and 4 ohm terminals. I am running Vandersteen 2CE signatures which are rated at 7 ohms nominal and 4 ohms minimum. I am currently using the 8 ohm terminals in my set up. Would I be better off using the 4 ohm terminals? If so, then why. If not then why not.
Thanks,
Eagleman
newbee
4,767 posts
 
Eagleman,

A simplified response -

If bass control seems to be a problem for you when you use the 8 ohm taps use the 4 ohm taps. If you use the 4ohm taps and the highs are not smooth use the 8 ohm taps.

Simply said, use the taps which sound best to you. My guess is that if you are listening at moderate levels the 8 ohm taps might sound best.
bartokfan OP
664 posts
 
Eagleman, feel free to ask w/o feeling you will get criticized. I get snides and insults due to lack of tech knowledge, snotty attitude, "mister-know-it-all", negativity, closed minded-ness. So as long as you don't follow me, you'll do all right here. btw I liked your question and Newbee's appropriate answer. I was not aware of how the 4 ohm and 8 ohm taps respond on different fq's. I still don't grasp ohm idea. Only that 4 ohm draws more volts/current from the tube amp. So it was a good question.
audiofeil
4,011 posts
 
>>I get snides and insults due to lack of tech knowledge, snotty attitude, "mister-know-it-all", negativity, closed minded-ness<<

You make stupid statements.

If you open the door, people will walk in.
atmasphere's avatar
atmasphere
11,850 posts
 
The point of the topic was to ask the GENERALIZED question that tube amps prefer 8 ohm speakers(though even 8 ohm speakers can dip to 4 ohms on huge orchestral challenges).

The answer to that is 'yes!', regardless of the tube amplifier technology.

The 4 ohm taps on almost all output transformers (excepting those that the 4 ohm tap is the *highest* tap). perform to a lower level than the other taps. The loss in bandwidth and increase in distortion is readily measurable and audible.

IOW: "Anytime you are investing in tube amplifier technology, that investment will be best served by a speaker that is 8 ohms or more, all other things being equal."
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