Denon has released a new power amplifier that has 10 channels at 150 watts rms per channel. It weighs 132 pounds. They also have a receiver that has 150 watts per channel x 7. It weighs 63 pounds. The amplifier is priced at $7,000 and the receiver at $5,200.
What is the difference?
The power supply.
Denon has made several high-end power amplifiers over the years. I was very interested in some of them back in the 1980’s.
The power supply is probably the most critical component in the power amplifier, and is really the foundation for great sound. It boils down to having a big transformer and lots and lots of capacitors. The quality of the capacitors is important, but probably not as much as just how much capacitance you have in there, because caps these days are all pretty good.
A sign that there is a nice power supply is the double-down of power output at half the impedance, and the Denon is rated at 150 watts with 8 ohm loads and 300 watts with 4 ohm loads. You won’t find that kind of spec in any receiver.
The reason mass market receivers don’t have big power supplies is very simple: the cost. Transformers and capacitors are the most expensive parts, and consumers want a lot for their bucks. A 4 ohm double-down rating is not part of that “want”.
However, the larger power supply also allows the designer to have some other benefits, one of which is not needing so much negative feedback, and perhaps not so many gain stages.
The SSP part of the receiver benefits from clean power, but it does not need so much of it. So, one thing you can do to improve your home theater if you have a small receiver is to purchase a better power amplifier and use the pre-outs from the receiver to drive it. In fact, this can improve your sound in a very big way.
So, the next time you are shopping for receivers or power amplifiers, look at the weight. Heavier is definitely better.