Tag Archives: Power Amplifier

Asheville, Walnut Cove, Biltmore Forrest and Western North Carolina’s Audio and Home Theater specialists present Cane Creek AV and Paul McGowan – PS Audio, Intl

Too many facts

The problem with facts is choosing which to follow. For example, it is a fact that regardless of which audio cable we use to connect the output of a power amplifier to our Audio Precision test equipment the results will be the same. Of course, that doesn’t mean the cables are the same.

As access to information increases so too do the available facts of any subject. Some facts are important to include while developing understanding while others detract or at best confuse us. If we’re designing an amplifier it’s best to stick to the facts pertaining to our specific design rather than chase factual rabbits down confusing holes.

How to choose which facts to follow?

Before the internet’s deluge of information, our limited research turned up end results that resonated with us: a product we liked, a person we admired, a book worth reading, a teacher worth learning from, a circuit worth emulating. Once a direction had been chosen, we could then dive deep into the facts that pertain specifically to that end result.

Today, we have a tsunami of facts and end results that may or may not be relevant, yet each can send us spinning off into the confusion of the weeds.

If we want to rely on the clarity of facts we need to make sure we are researching the relevant ones.

Pick a product, pick a guide, pick a direction, and then study the facts that helped shape it.

 

Asheville, Walnut Cove, Biltmore Forrest and Western North Carolina’s Audio and Home Theater specialists present Cane Creek AV and Paul McGowan – PS Audio, Intl.

I’ve used two passive “preamplifiers”, one of which you could activate an active stage, for more gain. I don’t use either now and probably wont ever again.

The potentiometer preamp

A preamplifier is, as its name implies, an amplifier before an amplifier. Preamps are typically placed between the source and the power amplifier. They select inputs, control volume, and amplify the signal to a level acceptable to a power amplifier. Simple, right?

Then comes along the idea of a passive preamplifier which is an absolutely incorrect usage of the name—a faux pas we at PS Audio did our best to correct. You see, to qualify as a preamplifier, you need to actually have an amplification circuit to…wait for it…amplify.

So, many years ago, in the 1970s, Stan and I used only an attenuator between our phono preamplifier and power amplifier. In our judgment, nothing was cleaner than a simple potentiometer or stepped attenuator to vary the volume. And we were correct, though cleaner doesn’t always mean better.

When it came time in the evolution of PS Audio to launch our own preamplifier, the debate between us was fierce. Passive or active? In the end, we settled on both and offered a switch for the user to choose between passive or active. But Stan, ever our beacon of straightforward naming, could not bring himself to call it a preamplifier since it was and it wasn’t, depending on the position of the switch. This drove me endlessly crazy as my vote was for simplicity—our customers wanted a preamplifier, dammit! call it a preamp. Eventually, we reached a compromise and called it a Control Center and, thus, the Linear Control Center was born: a preamplifier with the switch in one position, a passive control center in the other.

I believe after all these years that Stan was right and I was wrong to have argued in favor of simply calling it a preamplifier.

If it don’t amplify…