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?
You've done it so do you prefer the sound direct vs your preamp?  Your preamp being some 38 years old may be in need of a refresh and certainly a retube as suggested above.
Using an Oppo directly connected to Bryston amplifier can have high fidelity.  However, this combination could also sound a little sterile in a way.  Bryston amplifiers are usually very exacting and dynamic, but sometimes lack "life" - this could come across as being somewhat flat or sterile or non-engaging.  It depends on what the listener wants.  A preamp is used to help shape the sound.  The AR SP6 preamp could definitely add some life and texture to the sound.  You probably want to replace the tubes if they have not been touched since the 80's.
I guess I want the music as it is rather than with added 'life'.
Assuming you don’t create a major impedance mismatch, there’s no right answer.

The goal IMHO is your personal enjoyment. Your personal enjoyment may or may not align with any particular technical measure of performance. I mean, no one wants noise, or we think we don’t, but how low is low enough, and what are you trading off for lower noise?

There are some preamps like older Conrad Johnsons, which are pretty seductive liars. I doubt technically they measure very well, but I love to listen to them. In that case, removing the preamp from my chain is not what I want. Right now, I’m using a Mytek Brooklyn through a Parasound P7. The Brooklyn is more revealing and more relaxed sounding, but for technical issues I need the P7 in the mix. Kind of depends.

I will say I have had the chance to stream video from my Oppo (older BD player) and the Mytek, and the Mytek easily beats it for sound quality, but can't do 5.1 or 7.1


@audioconnection , +1.

However, since the OP has all the tools to do the test for himself, he is best to answer his own question.

He can simply listen to his system with, and without his ARC SP6 b and decide for himself.

Trust your ears.