How much do I need to spend to get a preamp that sounds better than no preamp?

I looked at the most recent service manual from Pass. It's got both revisions. The original has no such direct connection. The revised design really only attenuates the gain below the line level. The gain stage isn't on its own discreet ladder. 

In my experience, I thought I was looking for a magical mystical linestage that money could deliver, but I was actually trying to correct abnormalies in the speakers.  When the speaker were great, direct from DAC was glorious...but still open-minded.

It is a provisional patent, which has maybe been granted by now on this special circuit, he may not have given the secrete to how he bypasses the "active stage" in the the schematic so it runs totally passive, after all it is patented. I've seen other manufactures post schematics and leave out their special circuits. Why no Nelson.

His words

 "The only component in the signal path is wire and switch contacts."

This means nothing active in the signal path.
Same goes for my Lightspeed Attenuator there is nothing active or any switch contacts in the signal path just a passive ldr, yet it is powered by the mains for the leds to function. Yet it is a passive preamp with no gain.

Cheers George

I've looked at most of the schematics Pass has posted or published. Typically when he means to leave something out he posts a "simplified" schematic, such as you see currently for the F7. All the actual schematics in his owners and service manuals are sufficient to replicate the circuits it's describing, though not all the owner's manuals have full schematics. 

About $3500 if buying used. Or about 5-6K if you insist on buying new.

Always active (unless you get singularly lucky with the amp match) and almost always go with tubed preamps (unless you want to spend the big bucks).

Almost everyone tries to do without one and convincing themselves for the longest time that they don't need one and fighting wars on this point. You need a good preamp and they are rare. If your budget is under 8K for amp/preamp, a good integrated is always the way to go. My dealer told me this when I started my audio journey, I didn't listen, now 10 years later, I realise his wisdom.

I am using DAC direct as well, it beats most cheap preamps, but it still sucks, I am waiting to snatch the right used preamp : Shindo (Masseto or above), Coincident, Convergent etc.