Amplifier Talk - Essential Basics (12/03/2001)
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Dear Readers,

Joe once said: ‘‘People often ignore the importance of power amplifiers. The most common fault I observed: the power amplifier is too weak, unable to control the speakers’.

Indeed, it is true. For most setups I listened to, the amplifier seems to be the weakness link. However, people often blame it on the source, or the speakers. The power amplifier, however, received very little scrutiny.
 

What makes a good power amplifier?

A power amplifier consists of nothing but one or two transformers, some big capacitors, a simple board and a BIG heat sink.

In the older days, such as in the 70s or even the 80s, power amplifiers have the following pitfalls:

A. Big power amplifiers usually sound rough, but they are muscular.
B. Nice sounding amplifiers are usually class A and small amplifiers. But they can’t go very loud.

The above laws are already history. Today, big amplifiers can be more silky that small amplifiers of yesteryears.

For most of you who had been to 1388 office, you will be surprised by the amplifier we use - nothing but a YAMAHA. But you can’t deny it, the sound is delicate, warm, controlled and it certainly can go very loud.

This power amplifier was bought in the old Singapura Plaza Yamaha show room. My grand mother paid for it, as she knew I could not afford to buy anything else after getting a pair of Celestion SL60 anniversary Rosewood edition.

Why did I use the Yamaha? Well, like many, I was reading Hi Fi magazines and judged equipment not by listening, but by reading Hi Fi reviews. I was told that this amplifier could drive very low loads, and up to 1000W it still could maintain Class A operation. The SL60, like all SL6 or SL600 speakers, are power hungry. So I bought the Yamaha, without even listening to the combination!

It must have been more than 16 years now! But I still remember how thankful I was to my grandmother (she passed away a few years later), and how happy I was when I hooked up my system.

(I was then using a modified NEC CD player and a Carver Digital Time lens. Interconnects were Monster Cables, and the speaker cables were Audio Technica 6N. There were no preamplifier, as I intended to use the two volume knobs on the Yamaha as the volume control! I believe in: ‘Original Juice, Original Taste’, and thought that adding a pre-amp would degrade the sound. Honestly, I could not afford anything else.)

I also remember HOW DISAPPOINTED AND HOW ANGRY I WAS WHEN THE SYSTEM PLAYED MY FAVORITE CD. The sound was half dead, slow, compressed and blur! Compared with my previous system: Polk Audio driven by Yamaha integrated amplifier, it was awful!!

After two weeks of breaking in, I was even MORE FRUSTRATED. I paid the price of listening to Hi Fi reviews blindly and without auditioning the actual setup.

My Yamaha was ‘Cold Storaged’ since 1992. It was defrosted only in 1997, after I returned from UK. My mother used to put in the backyard, so you can imagine how old it is! But after servicing, it looks decent now. I modified it extensively in 1998, using the keys to good sounding amplifier:

1. The transformer must draw power efficiently, what ever its size.
2. The filter capacitors must be able to discharge the ‘juice’ rapidly.
3. ‘Feedback’, which is used on all modern amplifiers, must be adjusted so that the amplification is not more the 25 times. (this is a bit academic)
4. The amplifier should be properly biased
5. Signal coupling caps must be of high quality.

Some people asked me, well, all these can only be accessed by people who knows Electronics. For those who do not understand what is Ampere’s Law or basic V = IR, what to do?

Simple, Listen with YOUR EARS. Listen to more than a few power amplifiers on the same pair of speakers!

Some people commented: The Japanese listens with their EYES. Well, not just the Japanese, I believe visual excitement is part of the Hi Fi experience. For some people, it could be everything. If one feel that the amplifier is for the eyes, then may I suggest one should take up photography. It is cheaper and more fun.

If the amplifier has a efficient power supply, capacitors that can provide dynamic peak power, and electronics that are well designed, it will sound very nice, neutral and controlled. The speakers will reveal what the source is throwing at the amplifier.

If the amplifier has a poor power supply, (in fact almost 80% of current amplifiers are like this), and poor quality capacitors, it is hard for the speakers to do its job properly. I have seen people chaging speakers, but the real fault was due to the amplifier.