A Purely Resistive Load
I spoke with my father today. Circumstances forced me to give him my current home address. I don't think this will be a problem, but I've kept my home secret from him for the last five years for very good reason. The last time he knew where I lived, he showed up on my doorstep drunk, beaten, and looking for a place to stay. It was winter. I couldn't. I should say: I didn't. I didn't turn him away, though perhaps I should have. This was when I was living in Bloomfield and just beginning my career at Stereophile; I arrived home from work one evening to find him unconscious, in my bed, several empty bottles of vodka and one large knife decorating the floor. I suppose he was trying to kill himself. Or, at least, trying to make it seem that way.
An active line stage or preamp must offer voltage gain and/or current gain, or simply current gain. Current gain derives from a circuit called the buffer stage configured so the output matches the input unity gain. Voltage gain, on the other hand, is actually what's meant when referring to "amplification" taking a tiny wiggle and making a big wiggle out of it. Current gain adds current or "muscle" to the audio signal.
He began to shake and squirm in strange, unnatural ways.
I called the police, and the police called an ambulance, and together we watched as he slithered away.
The output buffer stage isolates the source and volume control from the load (amp) and your audio cables. The whole source circuit "sees" what's called a constant load no matter what the output is actually dealing with. The buffer stage also adds current gain, something like a mini power amplifier.
These are things I've really tried to avoid and deny in some backwards attempt at making my life simpler. And quieter. But, I'm only now beginning to see and understand that by avoiding and denying I've been allowing room for real pain and loss in my life. It's a constant and ever-present struggle, no matter how I pretend to be dealing with it. And, now, after all these years of crying and trying, I finally believe that the things I have in my life are too important to risk. I can do something about it, if I want to. I want to.
There are the three basic electrical elements all designers have to deal with: inductance, capacitance, and resistance.
After I gave him my address, he actually had to ask:
"How do you spell your name?"
I hesitated. Then laughed a strange, unnatural laugh.
"What?" he pleaded. "How should I know? Your mother picked it, not me."
I think he was joking. Or, at least, trying to make it seem that way.
Ideal audio cables would offer a purely resistive load with no other electrical influences disturbing the signal. A cable's inherent resistance is usually very low, less than maybe a tenth of an ohm; negligible as there's little or no current required to drive a line level signal. Also, pure resistance isn't frequency dependent, so, in this case, let's consider resistance benign.