Preamplifier power supply

Hmm, so those manufacturers are only implementing overkill power supplies for marketing purposes and the people who buying their preamps should know that they are in fact buying power supplies?

Chris

Yes you do need a good quiet power (toriodal) supply that keeps noise away from the circuitry - and big capicitance like on a big power amp is one way to do that. Of enormous criticality is how power supply is kept away from ground and how balanced the signal lines are designed with respect to ground.However, it can't be simplified to just that.

It is just as important to have features other than just a good power supply - balanced, high output levels with great channel separation and low output impedance and high input imepdance and of course low S/N. High quality tone controls with a "defeat" option for refernce. Volume control needs to be well implemented like with a discrete resistor network steps (like a crystal CS3310 or Burr Brown PGA2310) rather than just a cheap pot and wiper with continuous volume control, IMHO.

for example the built in preamplifier in the Benchmark DAC.

To me it sure looks like a pretty big overkill toroidal transformer in that little box...

Hi Chris . . . it's a mistake to so superficially "analyze" both the engineering decisions and marketing motivations behind any consumer product . . . it's true that there are many questionable design and engineering practices behind many specialist audio products - but simply looking at the size of the "power supply" (what does that include?) is akin to starting a thread with a title of "What's the proper diameter of a woofer?" . . .

. . . and if it's a mains transformer and filter capacitors you're looking at -- let's just say that dramatically oversizing these components is a pretty ineffective way of ripping off the consumer.