Audio research LS25 any opinions

I have just had my ls25 upgraded to the mk11 version, I was using nos tubes that made an incredible difference, I have not had the chance to evaluate them side by side but so far it looks like it's going to be a tight race. I would compare the two before doing the upgrade and keep in mind you are limiting yourselves to just stock 6h30's since I don't believe anyone else makes them, I did not think about the tube limitations before I had the upgrade done. just my opinion.

Gjc: What brand NOS tubes were you using with your LS25? What were the improvements over the ARC 6922's? Thanks

Gmorris email me for details.

Based on the recommendation from GJcooke, I purchased recently the 6H23 tubes from Upscale Audio. The results have been nothing less than spectacular. All musical parameters have been enhanced by this tube upgrade. The LS25 sounds like a brand new design with these tubes. I suggest that LS25 owners should try a tube upgrade before deciding to upgrade to the MKII version. In fact, I just ordered another set of 6H23 from Upscale, and have absolutely no intentions of ever "upgrading" to the MKII. Please note that the 6H23s are in fact labeled "Sovtek 6922" and appear to be identical to the ARC stock Sovtek 6922s. But beleive me, they sound substantially different: more robust,focused and powerful bass; better refinement; sweeter highs and midrange; larger soundstage with better layering and image focus. And to top it all, enhanced coherence and musicality. PHEW!!!!!!!

I did the same thing with the 6H23s from Kevin at Upscale with the same results as Gmorris... two thumbs up!! Also did the VT-100. The 6H23s do not work well with the DAC3MKII however. I think this has also convinced me to wait with the MKII upgrade... You can replace with these tubes 25 times (at current rates vs. the cost of ARC OEM tubes) before you will break even with the expenditure. There is also another level when some key capacitors are removed and replaced with Signature hotrod type D Infinicaps (use type S to mimic some of the other competitors sound).