Amp Designs That Are Able To Drive 4/2 Ohms Load


I have noticed that some amps like the Krell Evo 302 will output the exact wattage when halving the impedances ie. 300W/600W/1200W into 8/4/2 ohms respectively. On the other hand, some amps like the Bryston 7B-SST does not output the exact wattage when halving the impedances ie. 600W/8 ohms to 900W/4 ohms or the Plinius SA-100 (100W/8 ohms to 180W/4 ohms)

Can someone enlighten as to where the 'missing' watts have gone for amps that do not output the exact 2X the wattage when going from an 8 ohm to 4 ohm load? What are the criterias in amp design that determine which route to adopt, and what are the pros and cons of each design?

Thanks in advance.
ryder

Showing 1 response by elevick

Doesn't distortion go up as impedance decreases? Why design an amp for a lesser performing speaker? How many speakers actually are a stable 2 ohms, outside of car audio which has much higher distortion tolerances.

My one tube amp is stable at 2 ohms, but the same wattage output as 8 ohms. My other mono block tubes are stable to 1.4 ohms but put out the same wattage as they do at 16 ohms or 70 volts. Does this mean I'm going looking for 2 ohm speakers, NO. I'm looking for the best sounding speakers in my budget but doubt it will be a 2 ohm speaker. 8 ohms will probably sound better, why push my amps to the extreme?