Passive Preamp?

[Frank Berry]

Who came up with the term "Passive Preamp?"
The term is an Oxymoron.
If it's passive, it's not a preamp. A preamp is active ... not passive.

[Ron AKA]

It used to be common to use a transformer as a preamp on a moving coil phono cartridge. Moving coils produce very little voltage, but reasonable current. The transformer boosted the voltage. They were expensive, and considered superior to a SS powered preamp. An example below:

[Frank Berry]

A transformer is not a preamp. A transformer is an impedance matching device.
If the source impedance is low and the load impedance is high, you will get a voltage step-up. Many microphone preamps use step-up transformers on their inputs. The transformers are not, in themselves, preamps.

[Ryelands]

Originally Posted by Frank Berry

Who came up with the term "Passive Preamp?" The term is an Oxymoron.

And the argument is an old one: the point was aired often enough when passive controllers became fashionable in the early 1980s.

In the sense that a passive controller sits at the input to a power amp, it's not necessarily as daft as it seems - "passive pre-amp" rolls off the tongue better than, say, "before-amp box (with knobs)".

It's still pretty daft but marketing has always been a mystery to me.

[Frank Berry]

Passive Controller .... That's a far better description.
Thanks for your input.

[georgehifi]

Look at the word Preamp, what is it short for? "Pre= before" "Amp= amplifier"
It's saying a pre before the power amplifier!!!
The word preamplifier should never have been used in the first place, it should have just been called a Pre.

Make of this what you like, passive pre's should be called Passive Attenuator because the signal goes through nothing active and they only attenuate.
A Buffered Pre is an Active attenuator without gain.
And then you have an Active Pre with gain.

My 2 bobs worth anyway

Cheers George

[nigelwright7557]

Originally Posted by Frank Berry

Who came up with the term "Passive Preamp?"
The term is an Oxymoron.
If it's passive, it's not a preamp. A preamp is active ... not passive.

The amplifier in pre amplifier does not mean the pre am amplifies it refers to the box before the amplifier. This does not have to amplify it could simply impedance match or even possibly reduce teh signal if it is high already.

A transformer can be a pre amp too as again it doesnt have to amplify.

[enregistree]

For me, the right term is line stage.
It does not only attenuate, it also controls source selection (hard core solutions like georgehifi lightspeed being an exception). Other possible functions might be SE/BAL and BAL/SE conversion, fixed out (tape out) output… Not everyone needs all these functions.

Pre-amplification is not needed today with sources ~ 2VRMS and conventional power amps. Historically, it was needed for sources around 100–300mV and also term "preamplifier" ment that it includes phono stage.

[sharpi31]

It's not complicated.

The word preamp, in it's most literal sense, means nothing more than 'before amplifier'.

There is no intrinsic judgement made on the nature of the device, other than that it is designed to be placed before an amplifier.

So passive preamp is not an oxymoron. Nor is active preamp.

It's no more complicated than that

[Jonssen]

Originally Posted by sharpi31

It's not complicated.

The word preamp, in it's most literal sense, means nothing more than 'before amplifier'.

There is no intrinsic judgement made on the nature of the device, other than that it is designed to be placed before an amplifier.

So passive preamp is not an oxymoron. Nor is active preamp.

It's no more complicated than that

Explain a microphone pre-amp then....