Why do you need a preamp?

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Rclark

Why do you need a preamp?
« on: 21 Apr 2011, 02:32 am »

 Why do you need a whole seperate box to "step up low level signals"? Why can't an amplifier step those signals up on its own?

  To me it's like feeding pre-chewed grass to a cow.

cujobob

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Re: Why do you need a preamp?
« Reply #1 on: 21 Apr 2011, 02:41 am »
Some do, but amplifiers are not just for two channel listening.  There are also sonic advantages to separating pre-amps from power amps.

You can buy power amps with volume controls and also buy integrated amps.

Rclark

Re: Why do you need a preamp?
« Reply #2 on: 21 Apr 2011, 02:48 am »
It just seems like such a simple, mundane function to have a seperate box for, like having a separate volume control box for the seperate step-up-low-level-signals box.

stereocilia

Re: Why do you need a preamp?
« Reply #3 on: 21 Apr 2011, 03:13 am »
For digital sources, the preamp usually ends up decreasing the gain which makes the idea of a line stage preamplifier even weirder.  It's more like an active attenuation box.  Correct me if I'm wrong, but I think the preamp just gives the source an easier load to drive.  For whatever  reason, an active linestage sounds better to me than just putting a volume control between the source and the amp.  You'll find many who say otherwise.   

For vinyl, for multiple sources with tape loops, tone and balance controls and what not the need for a preamp is more obvious.

Rclark

Re: Why do you need a preamp?
« Reply #4 on: 21 Apr 2011, 04:20 am »
okay, that makes sense.

Sonny

Re: Why do you need a preamp?
« Reply #5 on: 21 Apr 2011, 06:28 am »
Also, you're using it to switch sources...A volume control on the amp is great if you only have one source.  The EVS Ultimate Attenuators are nice..plugs into any amp!
T

jtsnead

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Re: Why do you need a preamp?
« Reply #6 on: 21 Apr 2011, 10:33 am »
I have had multiple preamps, but I feel this is the best option with battery power supply:

http://doddaudio.com/BatteryPoweredTubeBufferPreamp.aspx




remote control with three inputs

JohnR

Re: Why do you need a preamp?
« Reply #7 on: 21 Apr 2011, 10:48 am »
Another factor that hasn't been mentioned is flexibility. If you have an active preamp, you can use different amps or types of amps (tube, SS, class D, monoblocks, etc). Finding a preamp that you like is the hard part, however... in the end, certain functions need to be performed and whatever way you find best to do those is all you need :thumb:

bhobba

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Re: Why do you need a preamp?
« Reply #8 on: 21 Apr 2011, 11:20 am »
Why do you need a whole seperate box to "step up low level signals"? Why can't an amplifier step those signals up on its own? To me it's like feeding pre-chewed grass to a cow.

The answer is you don't.  There are some mighty fine integrated's out there such as my Leben CS300XS.  In fact I tend to prefer them these days.

However if you go the separate pre-amp route then IMHO, and you will probably get people who definitely do not agree with me, its function is to switch inputs and impedance match - not amplify.  Most DAC's produce something like 2.5V and amps have something like 500mv sensitivity for full output.  Amplification is simply not required - unless you have some ham fisted recording engineer who records at some insanely low level - which occurs only extremely rarely (I have only one recording like that - a best of Aretha Franklin) - although of course it should never happen.  But even omn those recordings I still find I can get adequate volume without any gain.

Thanks
Bill

fsimms

Re: Why do you need a preamp?
« Reply #9 on: 21 Apr 2011, 11:41 am »
Ideally you don’t.  However, I like a solid state amp and a tube preamp.  I don’t know of any integrated amp that has both a solid state amp and a tube preamp section near as good as what I have.  Maybe the designs are different enough that it would be impossible to find an expert in both areas.

Bob

doug s.

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Re: Why do you need a preamp?
« Reply #10 on: 21 Apr 2011, 11:11 pm »
i need a pre for several reasons.  two (or 3) tuners, computer for movies, cd, turntable, dbx 3bx expander in tape loop...  and, a good (tubed) pre will make everything sound better than no pre at all.

ymmv,

doug s.

Elizabeth

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Re: Why do you need a preamp?
« Reply #11 on: 21 Apr 2011, 11:33 pm »
many years ago a preamp had a LOT of features.
Preamps universally had a phono section. They had tone controls, and a balance control. Many had tape loops.
ALL input devices, tuners, tape machines etc had aa electrical input voltage of 1/4 volt. maybe high end stuff got up to 1/2 volt.

Then a strange thing happened CD.

CDs had an output (for mysterious reasons to do with sales tactics only) a HUGE output of 2 volts. and even the gain of a preamp was neutered, and preamps became mere attenuators.

So gradually the line stage appeared. most phono preamps died off and line stages took over, with separate phono boxes. Then the tone controls vaporized. Defeatable or not out they went.

 Bad for audiophiles, and no respectable audiophile was allowed to own a preamp with tone controls. It was like having head lice. (The proper audiophile was supposed to buy $10,000 tone control interconnects instead, and did)

So now we have a nearly useless box with nothing to do.
I own three nice, nearly useless preamps;
Bryston BP-26
Audio Research Sp-15
VAC Standard.
All three have separate power supplies.

FULLRANGEMAN

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Re: Why do you need a preamp?
« Reply #12 on: 21 Apr 2011, 11:40 pm »
> Why do you need a preamp?

Good question. I can no see why I would buy a preamp, even an inexpensive one, as there is many power amps with a volume control, some even had a remote.

Many digital recordings are mastered with low price DACs or even expensive that use a cheap ''clock'' and this create a lot of ultrasonic digital noise in the disc, that cause auditory fatigue after some short time of listening.
So a good tube pre-amp may filter this digital noise, but a power amp also can do it if it had tube circuits.
Two cents.

> Never go to a psychiatrist, adopt a cat or dog from the street. On the streets pets live only two years average.

stereocilia

Re: Why do you need a preamp?
« Reply #13 on: 22 Apr 2011, 12:08 am »
With my Jeff Rowland Consonance I can switch the absolute phase on the fly, go from unbalanced inputs to a balanced output, switch from stereo to mono, store volume levels in memory for comparing two sources that have different output levels and switch instantly between them, connect more than one amplifier, or a pair of subwoofers.  I can instantly cut the right or left channel, mute, adjust the balance, and record from any of six inputs while monitoring the output.  I can connect to any amplifier or amplifiers I want with just about any length interconnect I need.  I can put the remote control sensor anywhere I want if I have a long enough DIN cable.   I can use either inverted phase or normal phase output jacks. 

So, are line stages useless if they don't have a phono stage or tone controls?  Mine isn't.  By the way, I compared this to an FT Audio LW-1 passive, and I had a hard time telling the difference, but I like the sound slightly better with the Rowland.  Same result with a Benchmark DAC-1.  I'm not absolutely sure I could tell the difference in sound with the preamp in or out, but I sure do prefer remote control.

ramante

Re: Why do you need a preamp?
« Reply #14 on: 22 Apr 2011, 12:42 am »
To me, functionality is the only valid argument.  Just a switcher, attenuator and a phono section if needed.  If you don't need this, then you don't need a preamp.  If you think you do, then your system is not well matched.  It's just an expensive tone control.

I've owned Audio Research, Aesthetix, Shindo and others and none have sounded as good as nothing.

Just my 2 cents. :)

FULLRANGEMAN

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Re: Why do you need a preamp?
« Reply #15 on: 22 Apr 2011, 01:19 am »
> ...and none have sounded as good as nothing.  :thumb:

Rclark

Re: Why do you need a preamp?
« Reply #16 on: 22 Apr 2011, 05:42 am »
Loving this guys, and learning a lot.  :thumb: :thumb:

jimdgoulding

Re: Why do you need a preamp?
« Reply #17 on: 22 Apr 2011, 06:53 am »
Gotta go with Fullrangeman.  Running an old Sony CDP into my active speaks was a revelation to what a preamp, least ways the one I had at the time, could do to add something to the sound.  It was clear, exactly, as a freshly wiped plate of glass, maybe none at all.  But, there was a deficiency in dynamic range.  My preamp fugues that exactitude up but in an acceptable way, I gots more illumination and warmth.  However, I would recommend trying it if you can.  I would if I still could.  My pre is more romantic, too, like me.
« Last Edit: 3 Jun 2011, 03:22 am by jimdgoulding »

Mark Korda

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Re: Why do you need a preamp?
« Reply #18 on: 22 Apr 2011, 07:30 am »
Hi R.Clark,this is the best question ever,great post....Elizabeth told the reasoning before me,man...she hit it right on the nail head,describing simply the true facts as I see in my mind,wow!I have been working on building switch boxes with the best attenuators,gold connections,silver wire,since what you questioned today.When cd players came out,Stereophile had a drawing of a simple passive preamp,and I've tried to build my own.I have some pictures I would like to show you,but I'm still working onto attachment pictures using Vista?R. and Elizabeth,my favorite preamp,one I will take to the grave,is the Ace Audio Zero Distortion preamp from ACE Audio.I have not heard of anyone on here that remembers this.The year was 1974,company owned by John Grauer.It was bare bones and cheap,but was the favored preamp by a blind speaker manufactorer Cizak.Sorry I'm rambling,but you two spark my audio intrest,if you have e-mails I might have the mental ability to send you the pre amp pictures,but I still have trouble attaching them to this post....I always need easy instructive help...thanks Mark Korda

doug s.

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Re: Why do you need a preamp?
« Reply #19 on: 22 Apr 2011, 11:21 am »
To me, functionality is the only valid argument.  Just a switcher, attenuator and a phono section if needed.  If you don't need this, then you don't need a preamp.  If you think you do, then your system is not well matched.  It's just an expensive tone control.

I've owned Audio Research, Aesthetix, Shindo and others and none have sounded as good as nothing.

Just my 2 cents. :)
i must respectfully disagree.  my system is well matched, but even if i didn't need the functionality, i have found that a good preamp will be able to increase dynamics and soundstaging w/o any masking of detail or degradation of timbre...

of course, for me, as i described earlier, it is a moot point, as i am always running at least two tuners, a cd player, a dvd player, a turntable, and a dbx thru a tape loop, so it's only in the signal path for compressed recordings.  and, remote control of wolume is nice, too.

ymmv,

doug s.