Can somebody tell me what a "passive preamp" is !?!?

Bill Ferris

Lunatic Member
I, as I have been lurking around this tube audio section, have run across a reference to a "passive pre-amp"..
Now my interpretation of this oxymoron is a chassis/or box with 2 or more stereo jacks input jacks with a selector switch for the selection of line level inputs to be routed to a set of output jacks with a attenuator(not a volume control) for controlling the level in it`s simplest form..

An of course, it being a totally passive device with no active parts inside it has not the ability to provide any gain("pre-amplification") !!

So why is it called a "passive pre-amp"?
Instead of a audio line level selector box w/attenuator which is what it really is..

I guess that wouldn`t be sexy sounding enough, maybe ??

Just curious about the name ? And I do understand the reason for the device..

You may commence to pounce on me, if you wish !!

Regards, OKB
 
It gets more complicated then that . There are different ways to attenuate . That holds the key of how they sound
I use the Dave Slagle AFC made volume controls . Then there is light dependent resistor LDR types and stepped resistors
 
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It gets more complicated then that . There are different ways to attenuate . That holds the key of how they sound
I use the Dave Slagle AFC made volume controls . Then there is light dependent diode LDR types and stepped resistors

Yes enginedr, I understand that it can be constructed with all manner of attenuator types with high quality high isolation selector switches, silver wiring and their effects on the sources SQ for better or worse..
But it`s still passive and not a "pre-amp" and that portion of it`s name should be dropped IMHO so as not to confuse newbies on this site..
Regards, OKB
 
I, as I have been lurking around this tube audio section, have run across a reference to a "passive pre-amp"..
Now my interpretation of this oxymoron is a chassis/or box with 2 or more stereo jacks input jacks with a selector switch for the selection of line level inputs to be routed to a set of output jacks with a attenuator(not a volume control) for controlling the level in it`s simplest form..

An of course, it being a totally passive device with no active parts inside it has not the ability to provide any gain("pre-amplification") !!

So why is it called a "passive pre-amp"?
Instead of a audio line level selector box w/attenuator which is what it really is..

I guess that wouldn`t be sexy sounding enough, maybe ??

Just curious about the name ? And I do understand the reason for the device..

You may commence to pounce on me, if you wish !!

Regards, OKB

I agree that 'passive pre-amp' is a complete misnomer, and even if "there are different ways to attenuate..." that doesn't mean that the box is not just an attenuator. The phrase 'passive pre-amp' must be aimed at people who are automatically accustomed to think that the thing that goes in front of a power amplifier must be called a 'pre-amp'.

EDIT: The OP slipped in while I was typing.
 
...that said, the thing about language is that it doesn't have to make sense. Usage dictates meaning and 'etymology is not destiny,' which explains why someone who drinks alcohol might be an 'alcoholic' but being a 'workaholic' doesn't imply the existence of 'workahol'.
 
Perhaps because a passive preamp has only passive components inside, no "active" gain stages, thus distinguishing it from the category of "active" preamps. Your description of a passive is exactly how I think about it too--an attenuator.
 
I agree that 'passive pre-amp' is a complete misnomer, and even if "there are different ways to attenuate..." that doesn't mean that the box is not just an attenuator. The phrase 'passive pre-amp' must be aimed at people who are automatically accustomed to think that the thing that goes in front of a power amplifier must be called a 'pre-amp'.

EDIT: The OP slipped in while I was typing.

Fair enough dyche01, until they try to connect their un pre-amplified phonograph outputs to it !! Trust me, there`re out there !!
Been in the audio service side + of the biz since 1975, and very little surprises me anymore !!

Thanks.. Regards, OKB
 
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Yup! Even worse: I remember being completely confused by the whole concept of 'pre-amplifier' when I first heard the word. I thought "Why not just let the amplifier amplify the signal."

'Passive pre-amp' is a whole different level of confusing, because the phrase makes no sense.
 
Some manufacturers used to call their pre-amps "Stereo Control Centers," which might be both accurate and descriptive (but it doesn't cover mono).

EDIT: e.g. the "Harman Kardon Citation IV Stereo Control Center"

stereo_control_citation_iv.jpg
 
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It is somewhat of a misnomer if it is interpreted as a pre-amplifying control stage in the usual sense rather than a control stage that is preceding the (power) amplifier.
 
It is somewhat of a misnomer if it is interpreted as a pre-amplifying control stage in the usual sense rather than a control stage that is preceding the (power) amplifier.

That's what I meant by "etymology is not destiny." The origin story could be retconned.
 
Perhaps because a passive preamp has only passive components inside, no "active" gain stages, thus distinguishing it from the category of "active" preamps. Your description of a passive is exactly how I think about it too--an attenuator.

Yes kward !! No active(amplification) parts in signal path, then only losses, however small, will occur, outside intentional signal level reduction via the "attenuator`s" settings(AKA. level control)..

I guess I `m old and not up on things, because when referring to pre-amps, my generation didn`t need to preamble pre-amps with active or passive, because almost all in use were active, though they were also sometimes called "control centers" which is what they did along with any signal boost that might be needed..

Thank you kind Sir.

Regards, OKB
 
Ok folks, just to be sure that my post is not misunderstood !!
I DIDN`T and WON`T debate the merits of the passive pre-"amp", as I have built a few in the past, one while waiting on parts for my Mac C28 in the mid eighties so I could listen to my CD player, stereo TV output, ect. and have some source selection and control over level..
And yes the SQ was "clearer" without the pre-amp.. No doubt..

But I sure missed having tone controls to roll off some of those early bright sounding CDs, stereo TV programs, Laser Discs.

Just the misnomer of calling a "passive" control box a passive pre-"amp" is what started me on this post..

No merits links do I need, so if you folks wish to hammer on about the pros & cons of a passive audio selector box with a attenuator, by all means, have at it.. On my side of the world, it`s Sat. and after 5:00 PM !!
And I`ve been told that I have a "Girly Boat Drink" :beerchug: (hey!! It`s a summertime FL. thing !!)in the fridge with my name on it... :D

Enjoy yourselves.. Take care..
Kind regards, OKB
 
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