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
Post removed 
You right, the best preamp is passive, with no amplification, If you power
amp  get  good gain and speakers get enough sensitivity , Take a look
Alexus preamp 
bache
 Take a look
Alexus preamp  
Very nice, a little expensive.$995 
You get the same type of volume control in the $699 Freya from Schitt. Plus you can switch it from passive (as the Alexus is)  to two different active buffer modes with a little gain for some added colourations, tube or solid state. And it has rca and balanced. 
http://www.schiit.com/products/freya 

Cheers George
The $699 Freya from Schitt seems like an amazing bargain for the price.
If I didn't already have something great, and were on a tighter budget, I would definitely be interested.
For passives, the only one remaining that interests me is Townshend’s Allegri+ which uses autotransformers that are wound using Townshend’s own Fractal wire and coated in ultra thin Mu foil. Unfortunately, it does not match my system well since it is single-ended only.