Low gain dac!

My rather complex desktop audio system has gain issues. They first emerged when I went from delta-sigma DACs outputting 1.9V to a NOS DAC outputting 2.5V. Gain issues worsened when I went from that NOS to another NOS w/3.0V output. 

There are all kinds of workarounds, and it's true that some volume pots are more linear at the extreme low/high setting than others. But I concluded that too much gain causes problems that are not easy to resolve downstream. I also know that a balanced DAC (which might be desirable for certain technical reasons) is impossible in this system: a DAC output 4.0-4.5V would wreck me.

@herman, 
You are correct.   Another common issue is poor  L/R channel balance when the volume control is  severely restricted to the very low positions.
Charles 

Is it possible for your pre to be sent back to the builder to have a separate gain control installed?  The reason I ask this,is myself and a few others here own Aric Audio tube preamps, and Aric installs a gain control on the rear of the unit. It is an awesome feature that I use whenever I swap in an amp with different sensitivity’s. 

I am experiencing same issue in my system as well. When first connected,  everything was great for about a year. Then I began to have the same experience as the OP has been having with the Volume Control.

Over the next few months the issue persisted and started to include the symptoms that Charles1dad described ".. poor L/R channel balance when the Volume Control is severely restricted to the very low positions." In fact I can only achieve L/R channel balance when the Volume Control is at the 5 o' clock position. 

I have sent both the CDP/DAC and Pre to their respective manufactures who swear, and I have confirmed, that they are working perfectly fine on their own. When connected - problems.  I thought that the problem might be the potentiometer on the Pre -TKD 2CP2511-MC/100K. Would changing this out resolve the issue? Any suggestion that may help the OP and myself would be appreciated.
  

Yes, the high output of many DACs and the high sensitivity (low V required) of many modern amplifiers creates this problem. Too much gain followed by too much attenuation.  Attenuators are best when not operated near full attenuation (<50%).  One reason passive preamps are popular. My system is built around a tube preamp with SS amp. Will likely add a tube amp as a alternative.  

My preamp has variable output gain. This requires two attenuators, one pre and post preamp gain. This is not ideal, a single attenuator would be better. However the gain control allows me to use use both attenuators within the best operating region. A compromise I am willing to enlist.