8 Vs 4 ohms


I have a Rogue (tube 55W) integrated amp that has 4 & 8 ohm taps. I have Dali Helicon speakers rated at 4 ohms and curretnly I am running them on the 8 ohm output from the Rogue. Does this hurt anything, what differences in sound could I expect running 4 Vs 8>

Thanks,

dan
djk
It won't hurt anything except it will sound different, only slightly perhaps, on careful listening. Typically at 8ohms the highs will be smoother and the bass a little loose. On 4 ohms you will have a tighter bass response and it may or may not effect the highs.
The 8 ohm tap will output more volts but less peak current.
Power = Volts x Current
= Volts x Volts / ohms
= Current x Current x ohms
Cford, The voltage at the 8 ohm tap is the same as at the 4 ohm tap, but the transfer of power to the speaker will be lower depending on the speaker inpedence. You are confusing the power consumption of the speaker depending on its impedence. The speaker at 4 ohms will consume twice the power of the 8 ohm speaker for the SAME voltage, if attached to the 4 ohm tap.
Tube outputs use transformers to match the voltage and impedence to the speaker requirements. Attaching a 4ohm speaker to the 8 ohm taps usually results in reduced power transfer and reduced damping, thus 'losser' bass. The opposite, results in stiffer bass, again with reduced power transfer. I find, that when in doubt, put the higher impedence speaker to the lower tap.
Bob P.