Interconnect suggestions for Audio Research Ref 5SE?

Cables make no objective difference in how a system sounds. You're fooling yourself and it's costing you money needlessly.

Definitely agree with you, Audphile1, regarding the Synergistic Excite. Definitely not a coherent presentation there as some bits seem to be dropped in from nowhere  as an afterthought. The air around the vocals at the beginning of Roxy Music Avalon, and the orchestral back up on Neil Young Harvest sound weird and not a part of the whole. There was more detail, but even parts of Allman Brothers Eat A Peach seemed picked apart, disjointed.

Listening to Cardas Clear now. Pulled the Synergistic Excite and installed the Cardas last night. Definitely a more coherent sound. Though the vocals at the beginning of Avalon still seem a bit disjointed. Big thing here is that definitely left feeling like I am listening to cables and what may be the Cardas house sound? Everything seems rounded off, filtered, ... rather like I'm drinking good bourbon from a styrofoam cup. Will give them another day or two as just added them to the system.

See several have mentioned Transparent. I may have to try them again and actually have a several year old piece of Ultra in my closet, far from the current model. I don't remember what they sounded like...Only that I chose the WyWire Diamonds over them quite a few years ago and that the nearest Audio Research dealer recommended Transparent at the time but is a total stuck up jerk and I wouldn't have bought cables from him... if only to spite him!

I have had the Shunyata Alphas in my analog line up for over a week now. Audphile1 used the term 'cool' when describing them earlier. Perhaps that's it. They have not had the presence, immediacy, detail, air I had been accustomed to with the Wywire and my LS 16. I'm going to drop them in my digital line up after the Cardas have had their chance. I'm hoping the used piece of Nordost Valahalla 1 will show up soon.

You need to leave Cardas Clear cables in place for a couple days to hear their full potential.  It’s not a matter of electrical break in; instead the upper tier Cardas cables have a number of hollow tubes inside and moving the cables causes a build up of static electrical charges.  The cables settle in after a few days.  This is all explained on the Cardas website.  

I am not a fan of cardas sound. I have not heard Clear but auditioned Clear Reflection recently. They were warm, wooly and had a bit of harshness in rendering sibilance. Kind of warm and bright at the same time. It’s very system dependent so if they work for you, great. I don’t think they’re bad cables. Just not for me. 
 

I know people are recommending transparent. It’s tough to audition. Unless you buy brand new. 
 

The original Valhalla could be good. Although that iteration/generation of nordost cables suffered from brightness and thin sound. I compared original Tyr to Tyr 2 and there’s no competition. Tyr 2 is a much better cable. Worth trying the Valhalla though. 

A lot of guess work going on here swapping different cables in/out every few days - and particularly an issue with any of the Cardas interconnects mentioned here. 

While TheCableCo offers a service to try many, I think it also adds more confusion if you don’t have the Cardas cables rested in place for several days - untouched. New cables are worse than used, and Clear, Clear Reflection, even Cygnus, open up and change more after they’ve sat in place and played for more than just a day or two. I've tested and compared this many times with identical pairs of new and used too, giving them at least 14 days and that's hard to do with short demo periods and too many cables getting rotated in/out back and forth. Oh well, best of luck.