Help with an ARC LS5 MK III

Hi all. I bought a used Audio Research LS5 MkIII to basically see what I was missing if anything. This Model has gotten rave reviews as being very musical and considered to be one of the best preamps that ARC made. This replaced a Sonic Frontiers Line 1 in my system. I've been listening for about 2 hours now and can't help but think that the Line 1 may be the better preamp.

With the Line 1, I have a mix of NOS tubes in there including a pair of Siemens and Ediswan. The sound is very detailed and smooth, but what bothered me has a tendency towards glare on dynamic passages.

I expected the ARC to be more holographic and just overall better, but it sounds like there's just a veil over the system. The soundstage is a little bigger and wider and the glare is almost gone but it's missing the bass slam of the Line 1 and the high end extension. The ARC still has the stock Sovtek 6922's in there but I've read on a few threads that some people prefered these.

I looking for some advice at this point. Is it the tubes, the cables or just me? Here's my associated equipment:

Sonic Frontiers Power 2
Cary CD303/100
Vienna Acoustics Beethovens
Cardas Golden Reference XLR's
and Cardas Neutral Reference Speaker Cables.

Thanks in advance for all the advice. Mike.
I have been using AR pre amps for years and have always found that the sovtek tubes are the first to go. ARC and many other manufactures use these tubes for their availablity. My favorite tube for the AR pamps are the German E188CCC.(US 7308) Most US and European Gold Pin tubes will give you more detail and less glare than the Russian and Chinese tubes.

I also use Mk 4 Black Diamond racing cones under my AR preamp and Mk 3 cones under the CD player, you can really fine tune the soundstage with these. Good Luck!
Can you offer me some help. I'm trying to decide between an LS5MKIII and LS25MKII. Any opinions? I'm awaiting delivery of a VT100MKIII. What phono stage would you recommend?

I have an LS 5 MK II, I am currently swapping out the Sovtek tubes and there is a big difference

Hi Marlin, Since I first posted the question, I've since changed the original tubes.I think part of the problem was that the original Sovtek were old and on the way out. I've replaced the tubes with NOS Amperex 7308 and they just changed everything. The LS5 MKIII is a tremendous preamp. I did have the occassion to hear the LS25 MkII at a dealer who happended to have it hooked up to the same speakers I have. It wasn't an exact A-B test, but as close as I was going to get. My impression of the LS25 was that it was more sterile than the LS5. The LS5 just offers more midrange magic than the LS25, IMO. Both preamps offer great resolution and soundstaging, I just wasn't impressed with the LS25 as it compared to the LS5.

The LS5 MKIII doesn't get talked about here on Audiogon that much, but those who have heard it say it is the equal of, it not better than the REF 1. In Arc's line-up, it would only be bettered by the REF 1 and REF 11. There's always alot of talk here on this forum and others about the SP10 and SP11, but both of those just can't compete with the LS5 MKIII.

To answer you last question, I use an ARC PH3 phono preamp and the two mate extremely well together.

As always, YMMV and it's best to try to audition both to see which you prefer, but you can't really go wrong with either. Hopes this helps.


I did get to compare the REF 1 against it at home - REF was clean and I loved the remote, but the magic was much more evident on the LS5 MK III. I have since upgraded the III with Infinicaps and am thinking about tube rolling.