Do preamps have a material affect on high level sources?


It would seem that a preamp is merely attenuating a DAC output. How can it alter the signal?
If it doesn't degrade the signal, would logic dictate that at best it has no affect.
Help me understand
vjpacor
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Thing is, modern preamps are so clear that even several of them in series hardly is even noticeable.
I generally agree with Lizzy, but in this case I must disagree.  IME, the preamp has a HUGE effect on the sound you ultimately hear from your system.  A lot of what you hear will be based on if your DAC can properly drive your amp, but there is no doubt a preamp will absolutely have a huge impact on what you ultimately hear.  I hope Ralph at @atmasphere will chime in here to check me, but my experience with several systems tells me the preamp is crucial in the ultimate sound quality of a system. 
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vjpacor
 It would seem that a preamp is merely attenuating a DAC output. How can it alter the signal?

The fabled perfect "active preamp" sound, has the "the sound of a piece of wire" and it does not exist.

Any active amplification circuit, whether it has gain, zero gain or negative gain. Will have, and add, it’s distortion to what the source originally has feeding into it, and they all sound different, there is no "perfect preamp"

If you feed your source direct into the preamp and it has a digital domain volume control, this is about as perfect as you can get, so long as you don’t "bit strip" with too low a volume setting on the digital volume.


Cheers George
George,
Your response is most consistent with the intent of my question. Thanks. But why then, isn't it common to drive a power amp with the variable analog output of a good DAC?
There are two ways to look at the question being asked, what you measure and what you hear. Different preamps DEFINITELY sound different in the same system. Whether they add coloration, distortion, or whatever else, is a matter of taste and what you like your music to ultimately sound like. The idea of daisy chaining several preamps is simply silly unless you want to show off your equipment rack.
By the way, the topic has previously been discussed ad nauseam and a quick search can/will prevent a long and pointless debate. 
My Benchmark DAC3 L is directly connected to whatever amp I happen to be running.  I also route my Rega RP10/Parasound JC3+ through the analog input to the main amp also.
I have not powered up my preamp since installing the DAC into the system last November.


A good preamp will have very low distortion at the levels needed to drive a power amp and wider bandwidth than the source.

The main things that a good preamp brings to the table is a better volume control than the ones found in most DACs (there isn't a good way to do volume control in the digital domain) plus the ability to drive the interconnect cable to the amplifier properly, so as to minimize the effects of that cable. I've yet to see a DAC that deals effectively with either of these issues.

We sell a lot of our line stages to digital-only people- they run the DAC volume all the way up so as to minimize the the damage done by that control and use the preamp volume instead. The preamp then can drive long cables where their DAC can't. In this way they report that the use of a good line stage is more transparent and more musical- more like real music.


Note my use of the word 'good' above; many line stages are not up to the fairly simple tasks I outlined above, and so do damage rather than help.
A question. Out of curiosity. Atmasphere you talk of how an active pre can minimize cable effects, and you know what you are talking about and not me. But thinking about that, I was wondering something else regarding the active pre’s effect.
Does the thing that provides the voltage or current or whatever on the sources output, 2 volts or whatever it is, effect the finalized sound? So does that 'thing on a source that provides the output' vary among source components? If so that may make a difference in choosing an active pre or passive pre for sound advantages? If so maybe the active pre is helping out a poorer signal coming directly out of the source in that regard over a passive? Just wondering.
^^Yes to all of the above.
Ok. That complicates things. Thanks atmasphere
But why then, isn’t it common to drive a power amp with the variable analog output of a good DAC?

There aren’t that many around, most are done in the digital domain.

But if you do have one it’s still fine, what you've got is a passive preamp but it's in the dac, same ratio rules apply. If volume pot is right on the output of a dac, so long as it’s 1:10 or higher ratio to the amp.
EG: volume pot is a 10kohm pot, and the amp it’s feeding input is >25kohm or more input impedance. (A 10kohm pot has a worst case output impedance of 2.5k) 2.5k into 25k there’s your 1:10 impedance ratio.


My Benchmark DAC3 L is directly connected to whatever amp I happen to be running. I also route my Rega RP10/Parasound JC3+ through the analog input to the main amp also.
I have not powered up my preamp since installing the DAC into the system last November.
You know what you do now? Sell the preamp and party.

Cheers George
vjpacor

Dac’s with passive analog volume controls in their outputs, and interconnect interaction, is a bit of a furphy.

Most good quality interconnects are much less than 100pF (picofarad) capacitance per foot.

EG: Say you have average quality cable at 1mt long and 100pf per foot, worst case is 300pf capacitance, this together with the dacs 2.5kohm analog passive volume control, will give you a high frequency roll off still at a staggering 212khz -3db!!!!!!!! Faster than most amps can do.
And if the cable is 2mts long it’s still at a respectable 106khz -3db!!!!!

So as you can see this talk about active preamps being able to control the cables capacitance, is a huge furphy, thought up by active preamp makers to aid in their product sales.

And by going direct, you don't get the coloration's/distortions that active preamps bring, if they didn't they'd all sound the same. Just like going direct!

Cheers George
@georgehifi 
 No surprise that a preamplifier OEM would respond with that rubbish. Pints for the house!!  I will miss the pretty tube glow however.
BTW my interconnect cable is 55 pf per METER, not so hard to overcome even when running 5 ft to mono blocks.
Yes that's fine, good quality ones are lower than 100pF foot.
  
Only if you've crap interconnects with high capacitance and over 4mt, does so called "driving the cable" become an issue As I said it's something manufacturers of active preamps have hung onto just to do scaremongering tactics with. 
I went passive a year ago ( Luminous Audio Axiom II, Walker Mod, 3 in, 2 out, single ended ), and never looked back. Enjoy ! MrD.
"...thought up by active preamp makers to aid in their product sales."

Funny to hear this from someone who floods these threads constantly pushing his own passive preamps. Just stick with technical inputs and leave out the editorials.


Only when going direct isn’t possible without "bit stripping" or if the source has no volume control, are passive pre’s the next best in line for transparency and dynamics, and yes that includes my one sunshine.

And not once did I mentioned mine in this thread or the last few months of threads, until you bring it up, and for that I thank you, for doing that and giving me some advertising, one could almost say you were shilling for the Lightspeed Attenuator, keep up the good work sunshine.

Forest and trees, if you can see them.
george, fair point. I should have said "pushing passive preamps" instead of "pushing his own passive preamps". But in your case that makes no difference. Either way, your remark to Ralph was completely unnecessary.  
kalali, you really are a very sensitive person. You comment on so many issues and so many remarks made by posters, and you seem to take things quite personally. Did you have a poor childhood ? Just sayin'. As far as the necessity of a preamp, it would be " system matching " dependent.  No hard feelings here. Enjoy ! MrD/
kalali
george, fair point. I should have said "pushing passive preamps" instead of "pushing his own passive preamps". But in your case that makes no difference.

Again thank you again for the semi plug.
And what’s wrong with "pushing passive preamps" they are the next best to going direct for transparency and dynamics, if the gain and impedance allows them, and in most cases they do, they are more transparent, more dynamic and less colored than an active preamp who's gain these days is not needed. 
There's been a heap of threads on similar subject. So reading this I again re-visited Direct vs. Active Pre-Amp.


As in all my previous findings a Quality Active Pre-Amp wins. Going Direct loses the emotion, soul, dimensionality, involvement, of the music. In fact I found going Direct became fatiguing after five minutes or so. A Quality Active Pre gets you closer to a Live Musical Experience.

I've done this experiment on numerous occasions over the years. Tube, Hybrid, Solid State, XLR, RCA, Active/Passive Speakers. Results have all been the same.

I've had a number of musical Pals place a Quality Active Pre. instead of Direct or Poor Quality Pre., on my recommendation. All have been gobsmacked at the Improvement in Musical Enjoyment.

I have had the opposite experience as initforthemusic. I hear more emotion, more soul, more dimensionality, more involvement, of my music. The start and stop of the musicianship ( prat ) has never been better. No more editorializing, no more coloration, so much more detail, in every category. Many people are afraid to give up their tried and true preamps. For $46., shipped to you from a California warehouse, is a single, one in, one out passive device by Douk Audio ( China manufactured ), an Ebay seller. After running my Luminous for about a year now, I wanted a passive unit for a 2nd system. This is an incredible little piece of kit ( superior, imo, to the Schiit SYS, in SQ ( which is good, as I borrowed one for a weekend ), providing you can live with one in and one out. An inexpensive way to try passive. I realize system matching is important. But my 3 dacs, several tuners and other sources all drive my many amplifiers I have, and my systems sound more " live " than ever. Enjoy ! MrD.
So as you can see this talk about active preamps being able to control the cables capacitance, is a huge furphy, thought up by active preamp makers to aid in their product sales.
Almost any audiophile on this forum has heard interconnect cables make a difference. In fact that is why there is a +Billion$/year cable industry in the US. This fact is incontrovertible.

It is the the fact that cables sound different that is why a good line stage is helpful- it is the artifact of those cables (IOW, not just capacitance) that a good line stage can control or virtually eliminate. Cheesy line sections and passive controls cannot do this.


If one needs an example of what I'm talking about, just look at almost any recording made in the late 1950s during the golden age of stereo recordings. At that time, there wasn't an exotic interconnect cable industry in the US (that wasn't to happen until years later when Robert Fulton produced the first high end interconnect cables in the late 1970s). Yet somehow Mercury, RCA, EMI, Decca and others were able to send delicate microphone signals up to several hundred feet apparently without serious degradation.

So apparently the technology to do that was around in the 1950s. A tech that is also not available to passive controls. It was done with active circuitry, with real engineering talent behind the design.


So when I say a 'good' line stage, I'm referring to one that is properly designed to include minimizing interconnect cable artifact as one of its goals. They are out there- you just have to look.
Atmasphere, can you name a few, as I am sure your preamps will be on the list ? Isn't that a benefit of true balanced designs ?
The balanced Backert Labs Rhumba would be a good example. Any preamp that supports the balanced standard would do the same thing. That is one reason balanced preamps can sound better- you don't hear the effects of the interconnect cable. 
Mr. Decibel
+1
I have two preamps.  One cost a pretty penny.  If I go direct I am bypassing 6 tubes in the preamp.  That will definitely color one"s sound. How could it not?
It just sound so much "cleaner" going direct to monos.  IME. YMMV.
Mr. Decibel
+1
I have two preamps.  One cost a pretty penny.  If I go direct I am bypassing 6 tubes in the preamp.  That will definitely color one"s sound. How could it not?
It just sound so much "cleaner" going direct to monos.  IME. YMMV.
Gotta stop this double posting,  My bad


oldtech0
I have two preamps.  One cost a pretty penny.  If I go direct I am bypassing 6 tubes in the preamp.  That will definitely color one"s sound. How could it not?
It just sound so much "cleaner" going direct to monos.


Yet there are those with vested interest in these $$$$ active preamps, in manufacturing, distribution or in retail to try to keep them alive and kicking, they will succumb one day, just like the poor old dinosaurs did.

Cheers George
Shoulda sold that video store when I had a chance.
@georgehifi

Then it's lucky I have some T-Rex Albums!
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