It’s the time of year for saving money!
What is a preamp? The basic description is “a device that serves as an input selector and router between the source and a power amplifier, that can attenuate or amplify the overall volume level.”
A Preamp can be a simple passive signal router with no power supply or active circuitry or it can be a complex multi-box multi-voltage device with highly sophisticated active circuitry. In either case the preamp does the same thing – get the signal from point A to point B with as little sonic deterioration as possible. The perfect preamp is “a straight wire with (or without) gain.” That’s a phrase I lifted from Stewart Hegeman, who was the guy who designed the legendary Citation line of tube electronics for Harman Kardon in the early 60’s.
Some audiophiles, especially those who have a room-based rather than desktop systems, sometimes notice that passive preamps don’t deliver adequate dynamic contrast because they don’t have adequate buffering between source and power amplifier which causes impedance mismatches that can suck the dynamic drive out of the music. My own experiences with passive preamps with room-based systems is mixed. Well-designed passive amplifiers, such as the Reference Line or Placette controllers were made to supply buffering. I’ve used the Reference Line in countless systems over the years with no negative effects. But if the cable length is long enough, say over 30 feet, even a well-designed buffered passive preamp might run into trouble. That’s where active preamps are the way to go.
If one of your music systems is a desktop computer-based system with short cable distances of one meter or less between components a passive preamp is an ideal choice. I’ve never experienced any dynamics or gain issues using a passive in my high-end desktop systems, and I’ve tried many combinations of DACs and power amplifiers over the years….
The only thing better than a passive preamp in a desktop system is no preamp at all. Many USB and Firewire DACs have built-in pre-amp functions. The Wyred4Sound DAC2 , Bel Canto DAC 3.5 VB, Benchmark DAC HDR, and the Weiss DAC 202 all have excellent attenuation systems that make an external preamp unnecessary.
Merely getting rid of the extra cabling and connectors (it takes an additional set of interconnects to put a preamp between a DAC and an amplifier) in a desktop system results in better overall sound regardless of what preamp you remove from between a DAC and power amplifier. That’s why I strongly advise anyone considering a USB or Firewire enabled DAC to look at units which include a preamp function. Less can be more, especially when it comes to pre-amps.
If you build a Home Theatre System built on 12v – 24v Amplifiers the audio feed that comes from your modern Wide Screen T.V. (And if you decide to use your Smart Phone, ditto) is virtually nil !
Meaning that the Amps are regenerating a very week signal in the first place (And that is why so many claim that 12v – 24v Amplifiers are junk)
The Audio feed is junk !
Now if you want to go with 110-120v AC Amps that you can just simply plug into your home wall outlets then get ready to put out big $$$’s !!
And for under $200 they (The online reviews) are mostly considered junk too ???
But if you amplify the Audio signal (On the 12v – 24v Amps) before it arrives to the main Amplifier/Amplifiers then the improvement is several fold !!!
And I know this just by chance (Luck if you will) ?
I have ordered an RCA Audio Line Booster to try and compare it to the by chance Subwoofer that has out Tweeter lines that can be tapped (3.5mm Jacks/Splitters – and plug into smaller 12v Amps) that improve the power (And Sound) again several fold !
Trying to boost a weak signal is fruitless, it’s weak, lifting the same signal to at least line level (Or a bit more) means a whole heck of a lot more !!!
Considering the above date is February 23, 2011 5:15 PM I doubt that this will even be reviewed so I will just stop at this for anyone who might read it…
Rick – Southern Califonia