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


Hello all.
I'm using an Audible Illusions L1 preamp and I think my system sounds better when I remove it from the signal path. Oppo BD105 directly to SMC Audio DNA1 Gold power amp. I have read that there is level of quality you need to hit before there will be an improvement in sound. I can't seem to find what that level is. Any ideas?
Thanks in advance,
Ben
honashagen
" Like so many things he's designed, it's a quirky component with a  narrow appeal ". I honestly cannot believe this has been said. NP has shared with the diy community most of his designs, which were all labors of love, not to make a dime. Give me, and everyone else a break !
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Maximum Gain 10 dB
Freq. Response +0, -1 dB @ 10 Hz and 100 kHz
Distortion < .1 % THD
Hm. We can do that with 1Hz to 400Khz, distortion at 0.01%. And that's with no feedback. And all tube, balanced.
kosst, he has many followers......geez,,,you are one of them. He never designed a product where someone could not use it. He caters to a wide variety of listeners, which is interesting because he almost designs for himself, going after his holy grail in design. As I see it, to listeners wanting the virtues of tubes, but want solid state, and has accomplished that. You just seem to be making fun of him and not giving the man any credit. Who is bigger than he in the diy world, and so generous with his knowledge. This is how I see it. 
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