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  1. #1
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    what is a preamp

    hi is a preamp a amp inside of a receiver and guess what im saving up eather for a reafoam job for my smaller advents or big aals or a used reciever for my smaller advents which would you choose i cant make up my mind?

  2. #2
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    A preamp is a separate component that accepts inputs from different sound sources (i.e. CD, tape, tuner, phono, etc..) let's you select the source, and then has a variable output (controlled by volume) which outputs the signal to a separate power amplifier that powers your speakers. Typically in home theater, a preamp is also combined with a processor to get a pre/pro combo. In a stereo receiver, there are both a pre-amp and amp section which do different things. In a digital home theater receiver there are the pre-amp, processor, and amp sections.

    Hope that helps.

    With your upgrade questions, how much money do you have to spend? What is the primary goal of your system? Do you eventually want a home theater or would you like to stay with stereo? Questions like this help a lot. If your primary goal right now is to make the room shake, such as in rap/electronic music, I'd recommend going on ebay or audiogon and get yourself a used POWERED subwoofer. Definitive Tech powerfields can do the job. I think ebay has some right now for pretty cheap.

    Good luck. Always keep in mind where you want the system to grow. I got into stereos back when I was in high school (~10 years ago when pro logic was mainstream) and didn't know a lot about them, so I made many mistakes, but I've learned a tremendous amount since then.

    Good luck and have fun!

  3. #3
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    The definition of a preamplifier has changed over the years to where it might mean many different things today. You must know what each one you consider buying does to see if it will meet your needs. Life gets more complicated. Once upon a time not so long ago, there was general agreement on what a preamplifier was and what it was supposed to do. At the core of it, it performs the necessary function of increasing and controlling the voltage from a source like a cd player, radio tuner, tape recorder, to make it suitable for connecting to the following stage, a power amplifier which provides further voltage and current gain to make the signal suitable to drive loudspeakers. A preamplifie also has provisions to switch from one source to another, contol the volume of the sound system, and usually has provisions to connect to a tape recorder for both recording and playback purposes. In one way or another every audio sound system, whether a $30 boom box or a $30,000 high end audio rig must perform the function of preamplification. However, that's where the agreed to definition ends. Here are the variables. A preamplifier, can be a separate component in a separate enclosure or it can be incorporated with a power amplifier (called an integrated amplifier), a power amplifier and tuner (called a receiver), or combined with just a tuner (called a tuner preamplifier.) In the good old days, preamplifiers routinely performed other functions as well. In the past, most preamplifiers had another stage of voltage gain which was arranged for different purposes. The main purpose was to increase voltage and equalize it for a moving magnet phonograph cartridge which typically has an output of about 1/100th to 1/1000th the level of a tape recorder or tuner. It also needs a very specific bass boost and treble cut to compensate for a complimentary bass cut and treble boost deliberately used in the production of phonograph records. This is called the RIAA curve. Many preamplifiers also had comparable high gain inputs for tape heads (as opposed to tape amplifier outputs) which had a similar but different equalization curve called NAB. Some also had high gain unequalized inputs for dynamic microphones. Preamplifiers also had controls to modify the tonal balance depending on the speakers used, the acoustics of the room, the shortcomings of the program material, and the listener's preference. Most had bass and treble controls, some had midrange controls, and some even had graphic equalizers built in. Switches for bass boost at low listening levels called a "loudness" or "contour" switch, and high and low frequency filters for reducing the annoying noise from scratchy records and turntable rumble were also provided. There were other controls on some models as well such as a "blend" control to reduce stereo separation, a gain control for a derived monophonic center channel, balance controls to adjust the relative loudness of left and right channels, and later on when four channel sound was popular, four channel models had a front rear balance control as well. When moving coil cartridges became available, an additional gain stage was added to some preamplifiers to accomodate their even lower output than moving magnet cartridges. If you don't have such a stage and need one, outboard pre-preamplifiers sometimes called head amplifiers and voltage transformers are available and perform the same function.

    In today's minimalist view of what a sound system should be which is popular among many audiophiles, many manufacturers have pared down the function of a preamplifier to its barest essentials. For most of them on the market today, all you get is a volume control, a balance control, a function switch to select inputs, minimal gain stages, many without phono preamplifiers which are sold separaely, and jacks for connecting the inputs and a tape recorder or two. There are even some so called "passive preamplifiers" which actually amplify nothing but merely provide a volume control, a switch, and some jacks for connecting your equipment. Because some sources like cd players have sufficient output to drive a power amplifier directly and because they also have their own volume controls, and because some power amplfiers have their own volume controls, if you have just one source to listen to, a preamplifier may not even be necessary at all. The cd player itself performs the function of providing sufficient voltage so that is in effect your preamplifier.

    Are there other variants and options? Lots of them.

    Sound confusing? You bet it is.

  4. #4
    Suspended topspeed's Avatar
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    Skep, that was one of the most thorough definitions of a preamp yet.

    Bravo.

  5. #5
    Silence of the spam Site Moderator Geoffcin's Avatar
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    There's even a whackier kind of preamp from Musical Fidelity. It's It's called the CD PRE24. It has a cd player, a stand alone A/D converter that works both ways so you can digitize analog inputs, switching for both analog and digital sources, and a phono stage.
    Audio;
    Ming Da MC34-AB 75wpc
    PS Audio Classic 250. 500wpc into 4 ohms.
    PS Audio 4.5 preamp,
    Marantz 6170 TT Shure M97e cart.
    Arcam Alpha 9 CD.- 24 bit dCS Ring DAC.
    Magnepan 3.6r speakers Oak/black,

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