Preamps can color sound considerably. Surprising?

Am I right in saying that most digital devices are designed to have low output impedance?

@antigrunge2 

No. They are likely deigned to have good sound and or good performance (which are not always the same...). Some have tube outputs and are designed to have as low an output impedance as the tube will permit... at any rate, low output impedance isn't usually the goal although its usually desired.

One of the main reasons we've sold line stages over the last 25 years and right to this day is that analog volume controls often outperform digital volume controls. With an active preamp you then set up the DAC to have the volume all the way up so there is no resolution lost, and then control the volume with an analog control.

The problem with a passive is the volume control is a series element with the output impedance of the source. This means the source impedance is raised quite a lot insofar as the interconnect cable between the passive control and power amp is concerned (and also as far as the power amp is concerned).  So controlling the interconnect cable, even if the control is 10KOhms is a lost cause. That is why passives are so susceptible to interconnect cable interaction.

My Tortuga passive and has plenty of power, punch, clarity and detail. Width is nicely presented and depth too.

I use a 1/2 meter  Audience IC that goes to a Modwright phono stage from the Tortuga.

I am using 1/2 meter Kimber KCAG IC`s from the Tortuga to my ATI 3002 amp. The ATI feeds a pair of Revel F52`s. 

I use a 1 meter pair of Zu IC`s into a Dayton Audio SA 1000 subwoofer amp which powers a Revel Ultima Sub 15 subwoofer. I have 3 other subs in the mix too.

This is my recipe for a very satisfying, enjoyable sounding system.

This works well and It will play as loud as you would ever want.

Try a Tortuga passive, you might be pleasantly surprised by what you hear 👍 

@scm yes ^that^ is a recipe.
We don’t know your source’s output impedance nor the amp’s input impedance.

So it is a nice story, but doesn’t answer why it seems to sound OK.
But we at least have a combo that is good, and we can say why it is good then that is even better.

I am pretty sure that it the witches brew of cables are good, and they are short, which is also good.

@holmz ...The source output impedance is VERY low according to what I see listed for my ModWright 9.0X phono stage. Couldn`t find anything showing exactly what it is.

The amp`s input impedance is 28K ohms

Every amp I own, and have owned, is / has been rated to reach full power with less than 2 volts at the input. If you have a good 2 volts to work with, impedances are well matched, and the system caters to your desired volume level ( s ), when does the preamp’s additional voltage kick in? Most preamps in most systems are still used in attenuation mode, ime.

@mrdecibel 

agreed, the discussion now seems to focus on the likelihood of impedance mismatchesbetween DAC and power amp, methinks. In attenuation mode, all a pre does is add distortion if impedances are properly matched. We are finally getting somewhere on this topic…