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.
For a few hunded you could sell your preamp and buy an LS 16 like I just sold and save a couple of hundred bucks at the same time. The LS 16 also uses Infinicaps. Also your preamp wouldn't appreciate hardly at all with the upgrade so that would be a loss if you ever sell it.
Warnerwh thanks. I did think of that before and decided against it. Your suggestion, though, is not an answer to my question. But thanks anyway.
Rather than pay the ridiculous upgrades through ARC, or even consider the lateral move to the LS16, check out the awesome value on this unit:

The LS2, LS15, LS16, LS22, in any kind of upgrade don't even begin to approach the incredible 3-dimensionality of the LS5. And this is a MK III with GNS upgrades.
I think I neded to be more clear in my original post, but I will clarify this a bit now. I don't want to sell my LS-15 and replace it with something else. All I would like to hear is if someone had compared the one with infinicaps to the one with REL caps. What is your opinion. What did you think was different. Worth sending for upgrade and be left without music for 3 weeks? Or live with REL caps and not bother with infincaps. Thanks.
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.
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.
I had the LS15 with Infinicaps for several years and loved it. But with the right tubes it really took the unit to a whole different level. If you havent rolled some tubes I would add that to your list. Some of my favorite tubes were the Amprex BB, Amprex A frame, and if I had it now I would try the Ei 6dj8.

Agree...those sovtek 6922 tubes that come with the LS-15 are not worth the effort. I did replace them with nos Amperex EC88 it is much smoother now. what is ei 6dj8? what brand is that?
I've been a cap fan for years,sustituting this cap for that in previous ARC Preamps.In general terms Rel Caps put out a nice midband reproduction,and image fairly well.Infinicaps
has this high freq. extension in air,which lead to a much broader and wider soundstaging of the device utilized in.
I personally own a ARC VT-60 Lenord told me it could be upgraded with Infinicaps as well.I may go that route myself.I could install my own caps,But ARC does other things to my amp I'm not familiar with and of course they would guarantee their work.Lenord did advise me in my situation with infinicaps expect more bass inpact and better high freq. extension which did not surprise me for him to say that based on my previous experiences with caps.
Audiophile 1,I and a pal had/have Audio Research SP-15 pre-amps,with built in phono.Not long ago both of us sent our units to Great Northern Sound for a major upgrade.I had previously,happily,owned the Sp-10,and Sp-11,however I liked the idea of the Sp-15's 3 tube phono section,as this afforded me the chance to tube roll(huge advantage)without robbing a bank.

Great Northern Sound(a great modder,BTW,though there's nothing wrong with using Audio Research,obviously)gave me a few differing,voicing options,Infinicaps,MIT's etc.I chose the infinicaps for my phono stage,as this was apparently going to give a more open and less grainy sound to my unit.The power supply,as I remember, had "Elna caps and A few Black Gate caps",as well.Not shabby,though my friend opted to spend an additional 600 bucks and go full Black Gate,in the power supply.I don't hear the diff,and we have almost identical equipment.

To make a long story short,if you like your unit,as I liked mine,resist the never ending push to sell your stuff.Other options are available,as in the Audio Research update,you mention.

With regards to the Infinicap update,both I and my pal are THRILLED with the improvement,across the board.Detail,resolution,and superb frequency extremes.I always have a good laugh,now,when I see the latest industry "push" to move to the supposed super(pricewise)units.It is just NOT the "big deal" that these megabuck units claim to be,as compared to a thoughtful,thinking hobbyist,that you seem to be.

I have another friend with the CJ "ART" unit.Sounds absolutely great.When I take my reference material over to his home I do not feel like I'm giving away anything,and I know I'm not rationalizing.Listen to your own intuitive perspective,and you'll not go astray.Good luck!!
He wrote "...Ei 6dj8". Ei is the abbreviation that a European company named something like Electrical Industries uses. They're available all over, are quite inexpensive, and certainly are among the best-value NP tubes around. Here's one source among many. I've happy with my results with Ei 12AX7s, 12AU7s, and Tube Depot.

On your original question, here's an informed opinion about capacitors--
Thanks. This is what I am talking about!!! Great suggestions. As I said before, I really like my LS-15 and just looking to improve the way it sounds. Selling it and getting something better is certainly an option in the future, when I really get sick of the pre-amp, but for now, I had it since 1999, bought it new, and still not tired of it. As for the tubes, I saw tubedepot on the web before, just dodn't know how reliable those guys are. Is it safe to buy tubes from them? I may check out these EI tubes. Thanks all.
"I saw tubedepot on the web before, just dodn't know how reliable those guys are. Is it safe to buy tubes from them?"

Christian at Tube Depot has treated me very well over many transactions. He has accepted returns when I ordered the wrong things and has bias-matched my old Ei KT90s to the new ones I bought from him for free. He's a good guy.

Based on the pic of the LS15 here , I'd say anyone who knows how to solder could replace those coupling caps with same-value better caps. Personally, I'd use the TRT D-Caps or Mundorf M-Cap Sup. S/Os, but you might also consider the V-Cap teflons, altho they're VERY expensive. But since you'd be saving the labor charge, maybe you could choose to afford them? Can you solder or have a friend who does?
Interesting thread. As an owner, I'd be interested in the different tubes as well. A few years back, I retubed with Sovteks from a dealer of ARC in Canada. When I got home, I realized that the factory set has a designation for each tube, V1, V2 and so on. The ones the dealer sold me had no such markings, and to this day I wonder if the damned thing is working right!
Can anyone explain the markings, and tell me if the tube sellers do the same so that each one is optimised for a certain tube socket.
Hi !
We are talking about the Infini caps in the signal path?
Anyone know when ARC changed from Rel to Infinite caps in the ls 15 .

Doesnt, ls 16 also have infini caps instead of Rel caps in the power section. Should these be changed in the ls 15 as an upgrade ?
LS-15 production with infincaps I think started on or around `'99 - '00. Also, along with infinicaps, ARC started making LS-15 with detachable power cord. Not being a big fan of replacement power cords, I don't care about that particular change
I ended up installing the new TRT Dynamicaps instead of the Infinicaps I planned to install. So far I have about 15 hours on the new caps and they are improving with every hour of use. Big improvement in the bass region, cleaner overall presentation. Sounds more natural now with better dynamics. I'm beginning to get used to the new sound and I like it. I think the sound will improve further with more hours/listenning time on the new capacitors.