Audio Research LS-15 Infincaps


I own ARC LS-15 pre-amp. Mine has REL caps. Later in production they equipped their LS-15 pre-amps with infinicaps. Has anyone compare the LS-15 with REL caps to the one with Infinicaps? If so, what are the advantages in sound of this pre-amp with infincaps vs the REL caps. I am thinking of sending my pre-amp to ARC for upgrade to infincaps. The price ARC charges is not a killer, but it's still few hundred bucks. Is it really worth it? Thanks in advance.
128x128audphile1
I just finished breaking in my LS15 after the infinicap upgrade and new tubes and dampers. I'm extremely pleased in every way, ARC was a pleasure to deal with, and it was only gone 10 days.
Jl35
I assume the upgrade had noticable impact? Resolution, bass... Where is the most change in the way it sounds now? Could you please xpand on it a little?
Thanks a lot.
Audphile 1,

I had both the earlier LS15 with REL caps and sold it for a BAT 5i (which I never really warmed up to...) about 4 months later, I sold the BAT and returned to the ARC and a later model 15 with the Infinicaps. My system remained the same otherwise.( then Plinius SA 100, VSA VR2's Wadia 23) I thought the sound was more linear from top to bottom. That is..better at the frq. extremes, although more subtle, and not huge in comparison. I gained a little air on top and less grain from my previous older 15 as I recall thinking.I was very pleased with the Infinicap 15's sound.

Just as a side note regarding the BAT...The BAT 5i, although very good sounding and was less grainy overall, more liquid in the mids, yet was more closed in sounding than the ARC.Sort of rolled off on top to me. THe BAt's bass was extrodinary and I did miss that extension and authority in the lower registers. Yet, overall, I thought that, at least in my system, both of the ARC LS15('s) had a more open, natural, and believable sound.

Jafox does have a good point however, and one which would be a very big step up from the 15 and 16 in going to the LS5 of any iteration,( Mk1,II, or III) especially with the GNS mod. That would be a clear winner sonically

If your keeping your 15 and upgrade it through ARC.. you wont recoup the cost of the upgrade should you sell it as Warnerwh rightly points out. and you would probably want to tube roll into something like a quad of Siemens/Amperex early 7308's or Tungsrams red print HM 6922. The Russian 6H23N-EB SLNM Cryo's tubes from ATSI are also very good in the ARC. Happy Listening! :)
The upgrade was significant to all listeners of my system. Initially I noticed it sounded fuller, richer, better bass. Then it just seemed improved overall, no downside. I felt it was a cost effective upgrade; I already liked the LS15, knew it was a reliable unit, didn't want to switch to another model. No regrets.
Thanks gents! I do like my LS-15 a lot, have it for long time and I am the original owner. I just heard that infincaps take this already fine sounding pre-amp a little further up sonically. That's the reason I was looking into upgrading it with infincaps. I will send it out for an upgrade now for sure. It doesn't cost that much and besides, I have no plans to sell it in a near future. I like its open sound and good soundstaging, imaging and overall reliability. Thanks again, but keep it coming if anyone has other suggestions for LS-15 upgrades.