Which NOS to use on Audio Research pre amp?

I have an SP10II - i use 6h23's in the line stage and Seimans in the Phono Stage. When i get a chance i'm going to try some EI elite 6dj8's in the line stage - i've used them as drivers in an amp and like them a lot in that application.

I do remember back a few years I upgraded a ARC preamp with Orange Label Amperex which was a great improvement.Amperex is a great NOS tube to start with and usually is not too expensive. Generaly each different manufacturers ( nos ) tubes have a unique sound so its important to know what your looking for,which will help steer you to the right direction. good luck

Gold Aero if you could get them.

I currently own an LS5 MKIII and I have tried the original Sovtecs and Telefunken E88CC (6922).

In my set up, I found that the Sovtecs put the soundstage at the front of the speakers and I was surprised that the instruments were very sharp and focused. I was expecting less than this, to be honest.

The Telefunkens, on the other hand, added more air and depth. This put the soundstage between my back wall and the speaker.

Note also that I also using an ARC VT130se amp that was modified by Great Northern Sound, using GE 6550 power tubes and Siemens 7308 input tubes along with Coincident Super Eclipse speakers.

Tube rolling, although frustrating at times, makes a huge difference, in my opinion.

Steve

Thank you everyone for your opinion. I will give the NOS tubes a try and swap out the Sovtek's which I think is making the sound bright, everything else seems to be okay, but I with the right NOS tubes it will improve.