Should I eliminate my preamp?


I have been using my Audio Research tube preamp and Bryston amp to drive Magnepan speakers for years. Recently I added a Oppo blue ray player to my system and connected directly to my amp using the balance cables. The reason was to eliminate the signal having to go through another piece of equipment before it hits the amp. Am I wrong or what am I missing?
elf1
Using a passive I know in my case that there is a real noticeable difference when I go from a 1 meter cable to a half of meter cable. I has a fuller more complete sound when I use a half a meter cable no matter which the five brands I have to try.
Using a passive I know in my case that there is a real noticeable difference when I go from a 1 meter cable to a half of meter cable.
If you hear this difference in length, either your interconnects are high capacitance or your passive or source is high output impedance.

Cheers George
Looking at your very nice system
https://systems.audiogon.com/systems/2186

Your D100 dac is no problem at 2v and 100ohms into the Lightspeed. And that at 2.5kohms using the 1mt of VH First at  61pF/mt is -3db at 1mhz!!. And your Belles Ref 150A needs only 1.4v in for full output at 100kohm input impedance which is no problem.

Looking at all this you have a prefect match up I can't see how there can be a difference between 1m or 1/2m of the VH First???

Cheers George
It really depends on how well the line out is on a unit. My Esoteric K-01 using the line out function is superb. It really shows how good the K01 is. But I need the preamp to power my sub which I cannot do without it. So a preamp gives you lots of flexibility, if I did not need that I could leave with the K-01 directly to my amp. In fact if I had full range speakers I would not need the sub and I would use the line out of the K-01. It's world  class. 
Your SP6 is not a very good preamp. My advice is to get a good more current preamp, something from at least the mid ninties as preamp quality took a giant leap at that time. As a general rule using a preamp is better than eliminating it even though this seems counterintuitive. If using a cheap preamp, eliminating one could produce better sound in some aspects but a good preamp will almost always be the route to better sound rather than eliminating one or for that matter using a passive one.