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

Luminous Audio Axiom mkII $199 (passive) - most impressive and significant upgrade in sound quality I've yet done to my main rig.  The best explanation I can come up with is the old audiophile cliché: it was like lifting a thick wet wool blanket off my speakers and my system already sounded spectacular and extremely resolving.

technics SL-1500mkII > Denon DL103 (re-tipped by Sound Smith and housed in modified wood body) > Jolida JD9 > Loung Audio Copla MC SUT/head amp > Axiom mkII > NuPrime STA 9 > Tekton Uruz speakers

*the Axiom has replaced three preamps I still have:  Accuphase C200, Jolida 3000B and a heavily modified Dynaco pas tube, all of which are fantastic preamps.  I have the 'base' model Axiom which means it's just one input and one output and volume control.  More ins and outs add to the price and they offer a 'Walker mod upgrade' which is supposed to be amazing but they run from $199-$999 depending on options.  Spending $200 to try one is well worth it as I will be getting one with more ins and outs very soon. 

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

$49 closest thing to going direct with a only potentiometer in the way.
http://www.schiit.com/products/sys

Or if you like to change the sound 3 different ways $699.
http://www.schiit.com/products/freya

Cheers George
honashhagen,
Many years ago Adcom had a pass thru line stage, touted as no coloration. I tried it with many amps. It did not seem to impart any color to the sound, yet something imho was missing. Well, not just imho... something was missing. The dynamics seemed compressed, and while there seemed to be minimal if any serious coloration to the sound (the bane of some preamps), there was also a lack of texture, space and fine detail. You know how when everything comes to life in music, the actual physical distance between the guitar and drums, the bass player... that was missing when compared to a good preamp. 
In fact the last comparison was putting a Gryphon Preamp, (very, very expensive) with any and all of the amps, all areas of aforementioned subtleties came to life. The preamp seemed to take the amp, even an Adcom 60wpc, to another level. It was a great thought experiment that I still remember more than 20 years hence.
So, I recommend a good preamp at whatever price you can afford... BUT experiment... you won't regret it.
Best,
Larry