These THD would have been alright 40 years ago but an amp that powerful would have been the cost of a car, would heat your whole house in the winter and would need 4 people to lift.
Not at all. Please check out Amirm's review of one of my NAD 2200's (manufacture date 1987-89) A very similar design (unfortunately 2 OHM did not get tested, which is how I use this particular one of my TRIPLET 2200's [for running a pair of custom homebuilt subs]):
le Area
Jun 9, 2020
#1
This is a review and detailed measurements of a refurbished and upgraded NAD 2200 stereo amplifier. It was bought by a member, sent to
QuirkAudio to be fully updated and then loaned to me. The work that Peter has done is exemplary. The inside looks brand new! I have repaired hundreds of amplifiers but never seen one this clean! So not only have the inside components been updated/replaced, but a lot of care has gone to cosmetically clean the unit. Peter sent me a long list of parts he has upgraded including reservoir capacitors and such. As a result, I don't know how representative of measurements are of stock units although probably not too far off. Used 2200 go for about US $530 on ebay.
The front panel is nice with an informative clipping indicator:
As you see, you can put the amp in bridge mode (which I did not test) and select whether you want soft clipping on. I left it off as you see in the picture.
During use the protection circuit came on when appropriate and nicely reset as if nothing had happened.
The NAD 2200 uses a dual voltage rail to keep power consumption and heat dissipation low when producing lower power and then upping the voltage for peak power. This is a common technique but usually applied to low baseline power level. Here, 100+ watts of power is provided using the low voltage power supply rail and it is only for power above that where the higher voltage is used. Technique worked quite well as you see later and kept the amplifier cool and happy during my testing.
Amplifier Audio Measurements
As usual, we start with our dashboard view of 1 kHz tone into 4 ohm load at 5 watts:
Not bad! Distortion is at or below -100 dB. With noise, SINAD degrades to about 93 dB putting the 2200 well above average of nearly 100 amplifiers tested to date: