Itching to upgrade preamp...

I used to go direct from the DS Sr to the XA60.5, but inserting the preamp added quite a bit more space and drive.

Sorry but it’s impossible, for the XA60.5’s 1.1v input sens, 30khom input impedance to "load down" and reduce the "drive" from the output of the DS Sr’s 3v 100ohms output impedance. All a pre can do in this case is add coloration/distortions, as well as the extra set of interconnects
Even Paul McGowen has said so  "The ability to eliminate the preamplifier in the system without any resolution loss is a major benefit to DirectStream’s outstanding musical performance."  

Going through the P12 the XA60.5 yes it looses a bit of low end slam

And this is telling you something that Nelson Pass would even object about.

There are other things you need to look at "if" both these so called apparent "fixes" are better to you.

Cheers George

The Luxman CL38U C is in this price range. The late Art Dudley rated favorably w/his Shindo. It was also rated Class A on the Tube Preamp listing. A big bonus is the phono section. Worth auditioning, if you can.

I am with georgehifi, on this. Passive is the way ( has been for me ). However, I understand the addition of a gain stage / extra circuitry, with the " drive ", " color " ( could be distortion ), that people like. It is all about " what you like ", as there really isn't a right or wrong. Besides, all of this, is quite dependent, on the particular recordings we listen to. Some, admittedly, can use some help...others, not.

How far are the fronts of your speakers from the back wall?

@soix about 8 feet. The speakers are well out in the room. If I move them further back towards the back wall, they loose the disappearing act that Audio Physic are famous for.