If a best Pre amp should sound as if there is no pre amp then why we need it ???

Sumerian

In all most all the reviews of any stereo pre amp, Reviewers keep saying how they are impressed that it sounds as if there is no pre amp in betwen their source and amplifiers.
if thats the case why dont they connect a source like SACD player directly to the amplifier why do they need to add a pre amp in between. Do they expect Pre amp to be switch box to swicth between different sources?

And then they also say how their system is improved with the addition of this component aren't indirectly reviewing their source component like a SACD or turn table???

steveinaz

Yep, preamps also provide switching for multi-source systems---and of course volume control if your source doesn't have an output control.

I run a passive linestage because I'm believer in the "less is more" camp. My DAC acts as my source "switcher" and of course analog conversion.

Sumerian

I had a completely different prepective of why one would add premium components.

So for all those premium price tags that comes with these premium pre amps is just for a switch box with volume control that dont do anything to the source?

we are paying so much for it, not to do anything :-)

EndersShadow

Your missing a huge thing that a pre-amp does..... VOLUME.

Not all CD players/transports/DAC's allow for volume control (remote controlled or otherwise). At a min you need a passive pre-amp (i.e. no power) to handle the gain aspect (adding or subtracting gain), so your not at full volume 24/7 with no way to go lower.

If you lookup Axiom they make a couple of really good lowish cost passive pre-amps that they will gain match the inputs to your speakers and amp. Its a totally passive pre-amp with very little there and not super expensive either... but you dont have a physical remote so you've gotta change the volume manually.....

steveinaz

Some don't care for the sometimes "sterile" quality of running source to power amp, and they prefer a little "flavor" and/or extra dynamic drive a preamp can provide. It's a personal preference thing. A good passive linestage won't harm dynamics or sound anemic, and provided it's volume control is of good design; can sound quite nice. You do have to make sure the input sensitivity of your amp is such that a passive will be able to drive the amp at full output, and keep IC's to/from the passive as short as possible.

I've never run into output problems and I have a 1mtr IC from the DAC to my passive, then a .5mtr from the passive to my power amp.

F1nut

The notion that a piece of gear should sound as if it's not there is pure fallacy. Everything has a sound signature, period.

mhardy6647

I spent the last few years using a strictly passive front end - autoformer volume control and a switchbox.
I have fairly recently moved to an active preamplifier. Here's why...

-- besides switching and volume control, even a simple active preamp can provide two (or three) things that can make all of the difference in the world: gain (voltage amplification), drive (current capacity), and/or impedance matching (buffering). In my case, the voltage amplifier stage in my amplifier needs a little more oompf than the line-level output of a source component provides. An active preamp gives me that. I am giving up a little transparency but I am gaining considerably more (for lack of better words) weight and authority to what I hear... and I like it.

The active preamp I am using right at the moment is pretty low-end; it's a hybrid design from headphone amp/amplifier designer (and peerless DIYer resource, IMO) Pete Millett. It was designed primarily as a headphone amp but configured to also let it be used as a "linestage" (active line-level preamp). I built one a long time ago -- for now, it's just stuck in-line between the AVC/switchbox and the power amp.

http://www.pmillett.com/file_downloads/ax_hybrid.pdf



Gary Kaufman -- New England vacuum tube amp, preamp, and Altec guru (www.the-planet.org) -- and I were talking about active preamps last month -- one of his comments struck me as quite profound:

Preamps need drive, not gain

It's not 100% universally true (sometimes one needs some gain, too) but drive probably often has a lot to do with a system's cojones in terms of sound reproduction.

tonyb

Sumerian wrote: »

I had a completely different prepective of why one would add premium components.

So for all those premium price tags that comes with these premium pre amps is just for a switch box with volume control that dont do anything to the source?

we are paying so much for it, not to do anything :-)

In essence, your correct but your forgetting about the quality of that volume control, switches, and the ever so important analog output stage which all can make or break the sound. Build quality is essential to any piece of gear, and that costs money, hence the differences in price. That however does not necessarily guarantee the more expensive pre is the better sounding one.

mhardy6647

Here, take a look at Dave Slagle's site for an idea of one flavor of good quality attenuators.
http://www.intactaudio.com/

More traditionally, a good resistive stereo stepped attenuator populated with high-precision, matched resistors will be pricey, too.

here's a not completely random example :-)
http://bottlehead.com/?product=submissive-volumesource-control-kit

... and another:
http://diyaudioprojects.blogspot.com/2012/06/diy-stepped-attenuator-volume-control.html


... all of which is a great incentive to DIY, from my (cheapskate) perspective...

tonyb

As far as a pre amp that sounds like it isn't there....I'll agree with F1NUT, anything you add either adds or subtracts from the final sound. Goes back to my assertion that coloration is actually desirable. We all like different levels of it, and music itself is a coloration of sound waves. I'll even go as far as to say those who seek no coloration in their playback system are simply chasing a ghost.

steveinaz

Probably the single most positive aspect of my passive, is the extremely linear fashion in which it behaves with volume increases. The sound just gets LARGER and LARGER, not pushing any specific frequencies ahead of anything else in the process. It may have something to do with the constant 9k load the Placette presents at any volume setting, but I don't know enough about electronics to speak intelligently about it---it's just a hunch...I also like the 250 stepped control, which allows you to get the perfect volume setting, with such a fine adjustment; having said that, I find the Placette "binary" light setup silly, and pretty much useless for figuring out the level you are set at. A digital number display would have been more practical.

mhardy6647

Constant impedance of an attenuator (like an "L-pad") will certainly help keep things under control.

tonyb

mhardy6647 wrote: »

Constant impedance of an attenuator (like an "L-pad") will certainly help keep things under control.

So will a constant open wallet...lol

mhardy6647

That's why I like to pick up the ol' soldering iron - I am a cheap SOB when it comes to hifi...

SCompRacer

mhardy6647 wrote: »

That's why I like to pick up the ol' soldering iron - I am a cheap SOB when it comes to hifi...

I always thought of you as thrifty, not cheap.....;)

tonyb

SCompRacer wrote: »

I always thought of you as thrifty, not cheap.....;)

"thrifty" is whats used to describe ones self to unsuspecting females. However the female decoding apps quickly interpret "cheapskate". lol

Lucky for many of us those apps weren't around when we sealed the deal.

mhardy6647

On the other hand... Mrs. H thinks I am profligate in terms of hifi spending.

Back to preamps, OK? ;-)

I will say this - it's hard to find a good preamp that adds more goodness than it takes away - cheap or 'spensive. I've experienced many, many preamps (including some pretty highly-respected ones) that make a hifi sound just a little bit worse with 'em than without 'em... which is what sent me down the passive route in the first place.

I have revisited my thinking on that (rather obviously).

zingo

Having run passive and active preamps many times, it all comes down to what are you looking for. Most passive preamp have no noise, low part counts, no maintenance, and are very simple. But generally, you do tend to get more ummph by using an active preamp. It all comes down to what do you want, and what sounds good to you.

Sumerian wrote: »

And then they also say how their system is improved with the addition of this component aren't indirectly reviewing their source component like a SACD or turn table???

Not if they know what they system sounds like without the preamp, and they observing the difference.

geppy1

I have to go with the NUT on this one .
"The notion that a piece of gear should sound as if it's not there is pure fallacy. Everything has a sound signature, period."
A bingo. It is a matter of what you like and what works with the other gear.

pearsall001

A preamp is nothing more than the control center for one's system. It's job is to pass the signal as unabated as possible but that's not going to happen when it comes to electronics. Pick your own poison on the sound signature that you like. To me as close to neutral is what I like. As any true audiophile worth their salt will tell you...the best preamp is "No Preamp"

F1nut

As any true audiophile worth their salt will tell you...the best preamp is "No Preamp"

That odd because I've never seen a true audiophile worth their salt not have a pre amp of their choice and every pre amp has a sound signature.

W WALDECKER

There is no such thing as the best preamplifier. the preference of what is best is a matter of taste and is purely subjective.

pearsall001

F1nut wrote: »

That odd because I've never seen a true audiophile worth their salt not have a pre amp of their choice and every pre amp has a sound signature.

Nothing at all odd about it. The preamp is a necessary evil that acts as control central. If it could be avoided then it most certainly would. But one does need something to be the brains of the system. Of course they all have a sound to them, all electronics do. That's where personal preference enters the picture. How much flavor does one want to add to their music. Even true audiophiles don't have much choice but to have a preamp, but they will still tell you that the best preamp is "No Preamp".

heiney9

Phil, a pre-amp is much more than a control unit. You should know that. A pre-amp is necessary in all but rare cases, then the pieces in question are designed very closely in tandem to work together and highly unlikely they would be the best choice separated.

pearsall001

heiney9 wrote: »

Phil, a pre-amp is much more than a control unit. You should know that. A pre-amp is necessary in all but rare cases, then the pieces in question are designed very closely in tandem to work together and highly unlikely they would be the best choice separated.

Brock, how much more than a control unit is it really? It's necessary because nothing would work without it in the vast majority of systems. Now it's up to the individual to make the decision on what best fits their tastes & system synergy. Maybe I'm over simplifying things but it is the command center that runs your system. I'm a simple guy. I don't like to over complicate things.

steveinaz

Years ago I decided (I was bored) to hook my CEC CDP directly into my HCA1500 amp, which has level controls in the back. I was amazed instantly at the clarity, linearity, and smoothness of the sound. At that time, I had been running a Musical Fidelity A3CR preamp; shortly after, I sold the A3CR and went the passive linestage route. I have never looked back or regretted the move.

adam2434

I've been doing a lot of preamp vs. no preamp comparisons lately.

The variable output of an Emotiva DC-1 dac/pre connected to my amps sounds significantly different vs. the same DAC with fixed output feeding a separate preamp (both a Cambridge Audio C500 and Parasound 2100).

With the separate preamp in the chain, there is good and bad. With both preamps, the sound is more forceful and dynamic - that's the good. However, the Parasound adds sibilance and edginess vs. the DC-1 direct. The Cambridge does not add the sibilance and edginess, but occludes some of the spatial cues and depth of soundstage vs. the DC-1 direct.

Granted, these are all "budget" components. However, the DC-1 is the most resolving DAC of the DACs I own, including a Music Hall DAC 25.2, Parasound Zdac, and MSB Nelson Link. Overall, I feel that connecting the DC-1 directly to my amps is the most transparent configuration vs. all other DAC and preamp combinations, but lacks the dynamics and bass slam of a separate preamp in the chain.

I can understand how a separate preamp in the chain could degrade the sound because it adds additional components in the signal path. However, I'm struggling to understand the how a separate preamp is adding the dynamics and bass slam that I hear with a preamp in the chain.

I don't think this is a gain thing. When I use the DC-1 direct (no separate preamp), I never listen at levels higher than around -8 dB (this is pretty damn loud). The DC-1 fixed output is 0 dB. Therefore, when listening to the DC-1 in fixed mode with a separate preamp at the same loudness, the preamp is attenuating the level vs. providing gain.

How can a preamp provide a more dynamic sound and more bass slam when it is attenuating the input signal? This is a mystery to me, but it's what I hear. If all of the dynamics in music are in the voltage swing in the original source signal, how can a preamp add dynamics? Or, is this really an impedance issue, meaning that the preamp is playing more nicely with the amps vs. the DC-1 direct? I've also read that the buffering that a preamp does impacts dynamics, but am not clear on the fundamental principles of that.

To paraphrase, what's the engineering/technical explanation for how a preamp could provide better dynamics and bass slam vs. the variable output of a source with no separate preamp, when the source output voltage is actually lower in the case of no separate preamp?

mhardy6647

It's (often) not the voltage gain, but rather the impedance matching - the ability of the source/preamp to 'drive' the first stage of the power amp - that makes the difference.

adam2434

mhardy6647 wrote: »

It's (often) not the voltage gain, but rather the impedance matching - the ability of the source/preamp to 'drive' the first stage of the power amp - that makes the difference.

A source has to be able to drive the input of a preamp. So, if one's preamp input impedance and power amp input impedance are the same (or similar), then dynamics/authority should be similar whether the source is driving a preamp or power amp directly. Right? Or is there more to it than that?

I'm wondering if the impedance matching factor is a big part of why preamp and amp combinations can sound different, but it seems like such a "random" variable. In other words, I don't think folks typically factor impedance matching into their preamp and power amp purchase decisions.

voltz

since I bought a Marantz SACD player I been trying some combo's like this to see what may sound best like:

Do i plug my Senn HD650's directly into the SACD or SACD > to WOO WA3? or SACD > to Vincent Sa-31 hybrid pre > to Woo WA3 ?

now when I go to my vincent sp311 hybrid amp the pre and amp are 47 K ohm but the woo is 100 K ohm.

so far I like the Preamp into the loop even though I defeat the tone controls most of the time, but I like the ability to play with the tone controls now and then.

tonyb

mhardy6647 wrote: »

It's (often) not the voltage gain, but rather the impedance matching - the ability of the source/preamp to 'drive' the first stage of the power amp - that makes the difference.

...and a huge difference in some cases. This is probably the most misunderstood thing in audio.