Vintage amplifier specifications

So two pair of speakers weren't necessarily amp killers in the days of yore so perhaps those old amps were more tolerant with beefier construction than I suspected.

Now days the low impedance load handled by amplifiers are selling points or bragging rights for manufacturers. Who doesn't love an amp that can "double-down"?

Many amps from the 80’s were rated not only into 4 Ohms but sometimes onto 2 Ohms as well. Big iron from Classe’, Krell, Levinson, Rowland, Threshold, etc.. Some even had more rated into lower impedances then than later on.

2 ohm impedance was the threshold for most designs of that vintage.  Even the original NAD 3020 would tolerate 2 ohm until driven hard and smoked.  Unsound is correct about big iron.  Include Yamaha, Accuphase, GAS and Luxman.

There were speakers of this era that really needed amps capable of delivering into low impedances, such as Apogee, Infinity, Thiel, etc..

@unsound 

As an Acoustat 2+2 and Apogee owner… I agree.