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

I bought the Ayre K-5xe and It's in getting upgraded to the latest version now.

Sometime back someone said at least $5000 is what you need to spend on a pre and I now agree. I'm borrowing a Parasound JC2 and it is very nice. I would say definitely better that no pre.  

And there we have it! Gain in a pre-amp is better! Science and listening do agree after all. 
Well had to give up the JC2 and am now borrowing a Parasound P7. Forget this one. Not in the same class as the JC2.
I got the Ayre upgraded to the MP version. Holy crap! More air and heft too. Absolutely worth the $850 charge.