Amplifiers - how big, how small? The truth.
We constantly receive emails from anxious customers asking which amplifier they should use with their Harbeth speakers. Will XYZ amp to too powerful? Will ABC amp not be powerful enough?
Of all the questions here, this amplifier issue seems to be the one that causes the most (needless) concern. Amplifier power capacity is a simple technical matter perverted by downright falsehoods, mumbo jumbo, irresponsible gossip and no concept of what an amplifier actually does. I've tried to allay these fears in various postings that I've made here over the years (clearly without success) so here for the final time is my opinion in one posting. Note that I have not made any comment about the claimed sonic benefits of amplifiers - that is another matter which I will leave entirely alone for you to decide for yourselves. But it's unlikely that there is a perfect correlation between amplifier power and sound quality. So let's just look at amplifier power rating.
Typical questions that you ask us almost daily and our answers ....
You ask: "Can I use a really powerful amplifier with my speakers? For example, can I use a 250W amplifier with my Compact 7s?"
My answer: It doesn't matter if the amplifier is rated at 50W or 250W or even 2500W. What matters is how you use the available power.
You ask: "Really? Surely the big amplifier has 'too much power ' for the speakers?"
My answer: No. It is irrelevant how big the amplifier is. The amplifier could be 1,000,000W (one maga watt).
You ask: "But surely that is too much power for the speaker?"
My answer: Yes, that is a huge amount of power but ... who is in command of the power? You or the amplifier?
You ask: "Surely the amplifier forces power into the speaker so that if the amplifier is too big (too many watts) it will destroy the speakers?"
My answer: Who is in command of that power? The amplifier doesn't have a brain. It is dumb. It is your servant. It does what you command it to do.
You ask: "What do you mean I am in command?"
My answer: Is your hand on the volume control? If so, YOU are in command of the amplifier. YOU and you alone decide how much loudness, how much volume and how much power will be made available to the speaker according to YOUR setting of the volume control.
You ask: "So the volume control is like a bath tap, and if the tap is only open a little, only a small stream of power will flow. If the tap is fully open, a torrent of power will flow. Right?"
My answer: Absolutely correct. YOU decide upon the power level you wish to deliver to your speakers. The amplifier doesn't sneak power past the volume control into the speakers! The volume control is the power-control gate and YOU control the gate! The water from the reservoir does not gush into your bath flooding your house - it is controlled by the tap.
You ask: "So the amplifier does not push or force the power onto the speakers, the speaker is permitted by me to draw power according to the setting of the volume control? So actually it does not matter how big the amplifier is, what matters is how I command the power by adjusting the volume tap."
My answer: Absolutely correct! You are the boss! You are in command. If you have a big amplifier act responsibly. Do not play too loud!
Alan A. Shaw
Harbeth Audio UK