Originally Posted by
whitebroncoii
"A 70V system is not constantly 70V. The 70V system output looks just like any other power amplifier. 70V is the constant in calculating power taps."
This is the part that I seem to be having a hard time understanding.I didn't know that a 70V system output looks just like any other power amplifier. So if I connect just one 8 ohm load (one loudspeaker) to the one 600 watt 8 ohm output of the amp then I shouldn't need a step down / line matching transformer? Is this correct? Only if I want to connect more than one loudspeaker to one 8 ohm output of the amp , say two or more in parallel, then I will need the step down / line matching transformer?
"70V speakers have transformers. Usually these transformers have four power "taps" or step-down windings".
My speakers aren't 70 volt from the factory, but I do have some 80 watt 70 volt transformers I could use one for each speaker. But if I am using only one 8 ohm load (one 8 ohm speaker) on one 8 ohm output of the amp (eight 2271 combined) do I still need the transformer at the speaker?
1W transformer tap connected to 8 ohm speaker = 5000 ohms [(70.7V x 70.7V)/1W]
5W transformer tap connected to 8 ohm speaker = 1000 ohms [(70.7V x 70.7V)/5W]
30W transformer tap connected to 8 ohm speaker = 167 ohms [(70.7V x 70.7V)/30W]
"70V loads (speakers with transformers) are paralleled to each other. Add the power taps and connect a 70V power amplifier 20% bigger (or more). It is perfectly OK to drive a single 5W load (loudspeaker with transformer tapped at 5W) with a power amp capable of 240W @ 70V. The amplifier does not care. It is not OK to connect ten loudspeakers tapped at 30W (300W total) to a power amp rated at 240W @ 70V."
SO... if I'm not going to parallel several speakers onto one output of the amp then I shouldn't have to use the step down /line matching transformer? correct?
one 2271 is rated at 75W into 66.6 ohms [(70.7V x 70.7V)/75W]
two 2271s are rated at 150W into 33.3 ohms [(70.7V x 70.7V)/150W]
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eight 2271s are rated at 600W into 8.3 ohms [(70.7V x 70.7V)/600W]
You could drive an 8 ohm loudspeaker, or a couple of loudspeakers wired for an 8 ohm load, with the full compliment of a 2280 (8 x 2271). However, there are lots of easier power amplifiers to use.
The reason I have all amps (8 x 2271) paralleled is so the output is 8 ohm, because if I split the amp into 2 channel of 300 watts ( 4 x 2271) + (4 x 2271) then the outputs would be 16 ohms and my speakers are 8 ohms.
I have 2 of these amps 2280A and each is set for 600 watts (8 x 2271) so if I connect one 2280A to one speaker and the other 2280A to the other speaker and connect left channel of preamp into one 2280A and right channel of preamp into the other 2280A then I should be able to connect one speaker 8 ohm with no transformer to each 2280A. Is this correct?
I think I get what you are saying about overkill and I guess if a person is not going to connect a string of speakers in parallel then he probably don't need this type of amp or this many watts.
thanks for your help