So whenever you go out to an audio equipment forum on the web, inevitability the topic of discussion will turn to resistors. This is especially true on vacuum tube audio forums. And the discussion always seems to come down to two entrenched camps; the Carbon Composition guys and the Metal Film guys. The Carbon Composition guys always claim that metal film resistors make equipment sound “sterile”, “dry”, or “cold”. The Metal Film guys counter with the fact that carbon composition resistors are noisy producing “hiss”, “pops”, “ticks”, or just “white noise”. And then the fight is on.

But I think there is something different going on.

I think that different people mean different things when they talk about the “tube sound”. I think there are some people (like myself) to whom the phrase “tube sound” is referring to the manner in which tubes (particularly in single ended amplifier configurations) produce rich harmonic content that reinforces the sound of music and speech to the human ear. This is exactly what drove me back to designing and building vacuum tube audio amps over four years ago. However, I think there are also some people to whom the phrase “tube sound” might also include a nostalgic remembrance of old equipment from the 1950s and 1960s. Faint reflections of childhood along with the memories and emotions that accompany them. And part of those memories is that soft hiss those old consoles made when there wasn’t any music playing. These distant memories can be very powerful and can drive our perceptions in many different and very personal ways.

Now today we know that it was primarily the tubes which were responsible for that rich harmonic content and it was the bulk carbon resistors of the time which produced that soft, sometimes almost imperceptible, hiss or white noise. So now when we choose to build we must decide what it is we want. Personally I love the rich harmonic content, but I like the background as deep, black, and silent as death itself. So this is how I endeavor to design and build my amps. However, someone with the desire to get that soft white noise deep in the background, someone truly looking for that classic sound of the last century, may be best served by the inclusion of a little carbon; carefully applied, maybe right up front in the audio chain. Something to bring that special sound and warmth back again; if just in a small way.

I guess it really shouldn’t be Carbon vs. Metal after all. It should be each of us designing for what we like personally. So, I say, build what you like; for the sound you want to hear of for the memories you want to stir.