Passive Pre Amplifiers

[poulkirk]

I am a little confused about Audiophile Terminology

What exactly is a Passive Pre Amplifier?

As I understand and believe, a Pre Amplifier is a device with Gain, to lift the Audio Level from a Microphone to a usable Line Level, or a Phono Pre Amplifier, a device with Gain to lift the level from a Pick Up Phono Cartridge to Line Level, and at the same perform RIAA Frequency response compensation to render the resultant Audio Frequency Response Flat or Level

Audio from Cassette Decks, DAT Players, CD Players etc comes out at Line Level, and is required to feed Line Level to the associated Power Amplifiers

Maybe the "Passive" Pre Amplifier is provided with a Gain Control, and "Horrors" Tone Controls, AKA Equalization, and usually also Input Source Switching

With this provided, it is no longer "Passive"

Maybe a better name for such a unit is a "Control Unit"

I am still confused about the term "Passive Pre Amplifier"

Only a piece of wire is a passive

Any clarification

[Jan Dupont]

You are right!

In theory a passive preamplifier is just a volume control pot (and in some cases also an input selector)...

Nothing to do with the word "Amplifier"

[moamps]

Hi,

Transformer passive preamp doesn't need power (with usually 3 or 6dB voltage gain).

Regards

[Brett]

It's simply semantics.
You are correct that Control Unit would be a more accurate description as a Passive Pre usually only contains an attenuator and a source selector (+ perhaps a mono sw and phase). However the term preamplifier has become known as the control unit so in audiophool terminology a passive pre is the same thing, lacking the active gain stage.

[mrfeedback]

Passive Preamp means Passive Attenuator, with maybe additional switching.
There has been discussion previously of a Passive Pre using a fixed series resistor and variable shunt resistor to provide level control - Fred Dieckmann's Attenuator
Of course this does not follow A-law curve, but in practice I have not found this to be objectionable.

Eric.