Phono Preamps: Amplification and Equalization

Behringer PP400 Phono Preamp

When the discussion turns to the phono preamps (short for pre-amplifier) we are really getting down into minute details of the record groove in order to understand its role and its importance. It is essential that you understand the role of the phono preamp as it will affect the decisions that you will make about purchasing equipment and ultimately the pleasure derived from your “Classic Vinyl Listening Experience”.

A phono preamp performs two separate but important tasks:

  1. Amplification of the sound
  2. Equalization of the sound

A phono preamp is the device that amplifies the sound that comes from the phono cartridge so that the main power amp can then further amplify the sound so that you can knock the pictures off the wall when you crank up the volume.  Without a phono preamp you can barely hear a record.  (Note: This occurs when you plug a turntable into an amplifier input labeled something other than PHONO on your amplifier).  This is because the PHONO input on your amplifier has a phono preamp (also called a “phono stage”) in its circuitry.

Stanton phono cartridge

To bring the explanation full circle, it is the job of the phono cartridge to turn the vibrations of the stylus into an electrical impulse.

A phono cartridge essentially creates an electrical signal because the stylus is attached to a magnet within a coil which as you may recall generates electricity when the magnet is moved back and forth within a coil.  But as you can imagine, the electrical signal that comes from a little phono cartridge is extremely small and hence the need to amplify it even before it reaches the main amplifier, hence the name phono preamp.

The second task of the phono preamp is called “equalization”

As you may recall, when a stylus is following the path of the record groove it encounters constant sideways movement (lateral, left and right, back and forth) of the stylus.  These movements are the sounds that you hear once greatly amplified. The movements with the widest back and forth swings are the very lowest and loudest vibrations.

This was a problem since the amount of space to allow for these movements back and forth was quite wide because the wide spacing greatly reduced how many revolutions the groove could make on the surface of a record.

So a method was devised to de-emphasize the lower frequencies when cutting (creating) a record, while also over-emphasizing the higher frequencies.  This allowed the record to be cut using less width so that more revolutions could be fit into the vinyl record and hence the improvement in playback time.

This is important: On playback the reverse is true.  The low frequencies are over-emphasized and the high frequencies are de-emphasized. This process has the overall effect of “equalizing” the recording. It’s like dividing by 2 and then multiplying by 2; you end up with the same answer. But this technique has the advantage of providing for more playing time on the record.

Officially, this process is known as the “RIAA Curve” for record creation and playback.

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The Classic Vinyl Listening Experience

  • History

    Intro To The Classic Vinyl Listening Experience

    Welcome to the Sound Exchange reference guide about vinyl records. On these pages we will explore any and all topics that are relevant to the enjoyment of vinyl records. Read more...

    The Emergence of Long Play (1948)

    The Classic Vinyl Listening Experience began with the emergence of the 10” and 12”, 33 1/3 rpm, Long Play, Micro-Groove, Vinyl Record in 1948, and its smaller sibling, the 7” 45 rpm record. Read more..

    Modern Long Play Records

    The modern long play, micro-groove record brought to the market had a tremendous impact on artistic creativity. Read more..

    The Modern Vinyl Record (1960s)

    It has a relatively long playing time and does so while reproducing sound in what is called high fidelity. Read more..

    The Classic Vinyl Listening Experience Timeline

    Let’s put all of this information in the form of a timeline. Read more..
  • Analog Vs. Digital

    Which is better, CDs or Vinyl Records?

    This question can be reduced to studying their differences. Read more..

    How Sound is Created and Heard

    This discussion begins with the creation of sound itself. Everything in nature that creates a sound creates an analog sound, which also happens to be the only kind of sound that we can hear. Read more..

    Analog to Digital Conversion

    The digital process begins at the point where the electrical impulses generated by the microphone are encoded onto a recording device. Read more..

    Playback Pros and Cons

    An analog recording doesn’t attempt to describe the sound as it simply records its input continuously, so it doesn’t have the sample size and sampling rate issues that digital has. Read more..

    What about CDs?

    First you must remember that the specification for CDs was developed way back in 1979. Read more..

    My Thoughts on Digital Vs. Analog Sound

    The vinyl record is my preferred media for active listening to recordings made in the 1950s and into the 1980s. Read more..
  • Stereo Recordings

    Stereo Recordings

    Any discussion about music and sound reproduction will eventually make reference to how it is presented to the listener. Read more..

    Stereophonic Recordings (1960s)

    Regarding stereo recordings, when stereo first came out it was a brand new world and exactly how to represent a recording in a stereo format was very subjective. Read more..

    Mono Vs. Stereo Recordings

    Beginning with the comparison of Mono and Stereo recordings, it was typical that both mono and stereo records were made from the late 1950s until around 1970 when they ceased production of mono records. Read more..

    Quadraphonic Recordings

    Finally let me touch upon quadraphonic recordings as they appeared on vinyl records. Read more..
  • Turntables

    The Record Player

    “For the record,” a record player is generally thought of as a turntable with a built-in amplifier and speaker(s). Portable units are typically record players. Read more..

    Anatomy of a Turntable

    The turntable has several basic components including the plinth (base), the revolving platter, the tone arm, the cartridge and stylus, and the mechanical and electronic components to make it all work. Read more..

    Reducing Unwanted Noise

    Isolating the noise generated from the turntable’s motor from the platter is essential. Read more..

    Choosing a Quality Turntable

    So how do you know how good a turntable really is regardless of cost? Read more..

    Turntable Belt Replacement

    Occasionally, belt drive turntables require turntable belt replacement.

    All about Phono Cartridges

    At the heart of any turntable system is the phono cartridge. Read more...
  • Other Stereo Equipment

    Classic Stereo Equipment

    Stereo equipment is one more significant variable that can greatly affect the Classic Vinyl Listening Experience. Read more..

    Phono Preamps: Amplification and Equalization

    When the discussion turns to the phono preamps (short for pre-amplifier) we are really getting down into minute details of the record groove in order to understand its role and its importance. Read more..

    Purchasing Quality Preamps

    Like all components of a stereo system there are significant variations in quality in the preamps, which has significant effects on the quality of the playback of your records. Read more..
  • Records

    On First Pressings

    Typically, a first pressing is defined as what the actual record album looked like when it first came off the manufacturing line. Read more..

    Grading the Condition of Records

    At Sound Exchange we use visual grading (as opposed to play grading) for our records. We do not grade jackets, only the vinyl itself. Read more..

    About 78 rpm records

    The 78 rpm record was the primary format for music sold during the period from the early 1900s into the 1950s. Read more..

  • Taking Care Of Your Records

    Record Storage

    Always store your records in a cool, dry, dark environment in an upright position (never flat) that is high off the ground, and that provides some airflow around them. Read more..

    Tips for Handling Records

    Always handle your records by the label and the outer edge and never ever touch the record grooves except when performing a deep cleaning. Read more..

    That’s Not a Scratch on Your Vinyl – It’s Dirt!

    Dirt and static electricity may cause good records to sound “scratchy”. A proper cleaning will remove dirt and static electricity from the vinyl. Read more..

    How Often Should Records Be Cleaned?

    Record cleaning, like most any other type of cleaning, is a matter of degree. Read more..

    Record Cleaning Solution

    Wet cleaning of vinyl records is the best way if not the only way to really get them clean and to get them free of static electricity. Read more..

    How to Clean a Record

    Use plenty of solution and really get the record wet while being very, very careful to keep the solution off of the record label, as it will cause the paper label to “rise” or stain the label, etc, and it will never look like new again. Read more..

    Salvaging Vinyl

    An old trick of “last resort” is to actually play a record while wet. Read more..