Opinions on Audio Research LS17 & LS26

I recently compared my LS-15 (with attached power cord) which had high-end NOS tubes in it with the LS-26 in the dealer's showroom. The LS-26 had a better more focused soundstage and a quieter background which allowed for better microdynamics. The only thing I preferred on my LS-15 was that it had more of a lush (rich/warm) sound (the tubes?) which made the LS-26 sound slightly sterile in comparison. In the end, I decided that the improvement the LS-26 provided was not worth the price. I may look into sending my LS-15 to GNSC for upgrades.

Ackman00, Interesting comparison between the 2 preamps. I wonder what the dealer thought about it.

As a side note...if your LS-15 has captive power cord, it probably also has the yellow REL caps. Replacing the REL caps with TRT Dynamicaps was a huge improvement in my LS-15. I also had the IEC installed to try the aftermarket cords.
LS-15 is a fine preamp, but you can definitely take it several notches higher with an upgrade.

Agree Audphile1. I too replaced the stock infini's with TRT's and the preamp was far more transparent/neutral. This was a good thing in the context of my system. The LS15 with the EH6922's and new dual tube dampers from arc, plus the TRT's IMHO,take this pre into the "high value" category.

Audphile1, thanks for tip on replacing the caps - do you know where they can be purchased? The audio dealer I visited (Stereo Design in San Diego) has a very low key approach - they let me listen to whatever I want and don't "push" any of their products. They know they carry great stuff and just want me to be happy with whatever I choose - so they did not care that I was not going to pull the trigger and purchase the LS-26. They probably figure I'll eventually purchase one of their other products at some other time (and they are probably right).

Dpac996, I regret I didn't change out the power supply caps on the LS-15 though. I should have replaced those Nichicon caps with some Black Gates. Could have been even better!

Ackman00, see www.percyaudio.com
I purchased capacitors from this website. Michael is a pleasure to deal with. If you are going to purchase TRT caps, I recommend you also investigate the possibility of changing the power supply caps to BlackGates. But the TRT Dynamicaps along should bring a very nice improvement.
I think this upgrade is totally worth it. Improvements across the board, especially comparing to the REL caps ARC used in this pre.