Journey or destination?
One of our forum posters asked an interesting question this morning. “Why don’t you just copy the speaker Arnie Nudell built already? Why improve what has already been established as a masterpiece?”
To me, that question is better stated as move forward or sit still?
It’s nice to sit still and enjoy the fruits of our lives. I do it nearly every day when I hear my stereo system, drive my car, converse with friends and family, relax in my home. I look at this as a rest stop, a chance for reflection.
When a reflective, stationary, existence becomes a way of life, we often think of a monastic or retired person.
For me, life’s a series of brief respites coupled with constant forward motion: learning, growing, contributing. Infinity System’s founder, Arnie Nudell, was like that too. As soon as he signed up for our speaker project his sleeves went into automatic roll-up mode. “Let’s build something better,” was his battle cry.
I am more interested in the journey than the destination.
For those interested, here is how an audio power amplifier works.
Peeking under the covers
It seems I may be alone in my enthusiasm to read about high dynamic range loudspeakers and systems in these blog posts so we’ll move on. That’s fine, it’s just that I am currently immersed in the subject because of our work on the new line of Arnie Nudell speakers. We’ve had some excellent work finished by our driver manufacturer including a new midrange ribbon that has me swooning!
That said, I’ll keep on getting excited about high efficiency, high dynamic range solutions, but meanwhile, we’ll switch gears on these posts.
One question I get asked a lot is how a power amplifier works. Generally, the question comes up because power amplifiers seem somewhat of a mystery. Big, heavy boxes, with collections of strange components inside.
To start off the discussion let’s imagine the use case for a power amp—one we’re all familiar with: an input to connect the output of the preamp or DAC, and an output that connects to loudspeakers. What happens in between? We know a preamp is incapable of driving a speaker because it doesn’t have an essential element. Wattage. So, what happens? How does the power amp take the weak output signal from the preamp and give it wattage, muscle, power?
Let’s start with a simple diagram of a power amplifier.
Note there are 3 blocks. An input amplifier (U1) an output amplifier (U2) and a power supply. These are the three critical elements within any analog power amplifier. The 3 elements are:
- Voltage gain stage
- Current gain stage
- Power supply
Tomorrow we’ll start with the voltage gain stage.