Do preamps have a material affect on high level sources?

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

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. 

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.

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. 

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

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
 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