Can a simple DIY volume knob replace a pre-amp?


If I have only a cd (single source, can I make a simple volume knob instead getting a pre? Since it is simpler and "pure", will the sound better? I know Pre-amp will do some gain on the signal, what is the benefit to have that gain? I am shopping for a pre-amp and come across some people said that a simple volume can replace the pre. Thanks.
waip7

Showing 1 response by ngjockey

There are 3 basic analog volume controls.

Potentiometers are the least expensive but capacitance and inductance can affect the sound. There are some well regarded brands such as Alps.

Attenuators use individual resistors and can be anything from simple rotary (step or ladder) to remote and semiconductor controlled (usually not for DIY). These are usually better than pots but can be difficult and expensive to assemble. The exception might be DACT units. The main drawbacks of resistance based units is reducing dynamics at lower settings and the requirement for low output impedance of the source. Placette is highly regarded due to high quality parts. The upside of passive "preamps" is incredible transparency.

The third and newest alternative is transformer volume controls (TVC). The Electraprint is the least expensive I've seen. Congratulations, if it works. There's also Sowter(IAG) or S&B (Bent Audio). These also require equipment matching but there is no loss in dynamics. I built one, as an experiment, for less than $1000 and it blew my reference quality tube preamp right off the rack. The other nice thing about TVC's is that they are completely indifferent between balanced and single-ended (autoformers excluded).

Of course, there's always Aunt Corey's but the BUF-03 has been discontinued.
http://www.stereophile.com/amplificationreviews/54/index1.html