Recapping an ARC LS-5 mkiii

So I have done an exhaustive Internet search on this, and have some answers (but not all).

Every piece of audio gear I have from the 80's and 90's has had some sort of issue and needed mods and/or repairs. Some of this wasn't audible, but showed up when the equipment was put on a test bench.

Every piece of classic/vintage equipment I have (Aragon, Sonic Frontiers, Audio Research) has been updated except for my LS-5 mkiii preamp. With ARC gear, I know lots of people tend to think of them like classic cars and look down anything ARC didn't do originally.

At the same time, I know ARC offers a Stealth Cap upgrade (roughly $800 IIRC) and I also know Steven Huntley at GNSC used to modify ARC gear (including the LS-5), but I can't really find anything out there on what that process involved.

I am interested in getting the Stealth Caps done, however, outside of that, I don't want to change the sound signature too dramatically (like shoehorning an LS V8 motor into a Mazda RX-7). I'm sure there are some gains to be made (Rel Caps to Infinicaps?), but want to make sure I do things the right way.

BTW, the preamp sounds good (to me), but as I've learned, that doesn't always mean it would test completely within spec.

Thanks in advance.


It is best to let ARC do the upgrade.  At least you won't kill the resale value of your preamp and you know it will be done professionally.  

Avoid capacitors whose manufacturers don't specify a ESR or a ESL number.  Anyone in a garage can make a cap that works but the equipment to measure ESR and ESL is expensive and you do want those numbers.  At least you have a very good idea of what the capacitor will sound like, assuming the numbers are honest.

Slim to zero chance ARC will work on the unit if it has obsolete semiconductors (they can't take the chance they'll accidentally damage an irreplaceable good one while in their care). 

The Rel Caps are top quality films which ARC uses as bypasses in the power supply. I don't know what they use in the signal circuit. I think you may be doing a sideways upgrade if you replace the Rel Caps. I look for old damaged ARC gear to harvest the Rel Caps.

LS 5 mk 3 one of the all time great pre from ARC a true classic believed to be the first REF. Pre they made. I always wanted one and would buy the right one in a heart beat and would also upgrade the caps. Extremely rare to fine one for sale showing how treasured they are.

Agree you have a great preamp. No doubt caps have come a long way since that baby was made. As mentioned I’d start with ARC but I’m sure there are many techs more than capable and some here that will use better caps than what ARC uses and not take your head off on the labor. If you’re not confident you can do this personally, then don’t make this your first project. 

Have you checked the tubes recently , if not you should as the maybe ready.

@gs5556 appreciate the heads up. I’m still learning all the ins and outs on caps/etc., so thanks for clarifying.

@tecknik Thanks. Yeah, I jumped on it last year because I know they don’t come up very often and I really wanted to see how well it paired with my Vandersteen 3A Sigs (it works pretty darn well).

@adg101 I certainly have a tech who is capable...and that ain’t me lol (A guy I know who has rebuilt my Aragon equipment and has a pretty good reputation on DIY Audio).

I’ve reached out to ARC on what may be involved. I contacted Pyramid Audio who resurrected my "unserviceable" (per ARC) D400mkii and it sounds pretty darn good...but Pyramid hasn’t seen a ton of LS-5’s and they’re risk averse to modding or changing anything.

I took out the original Sovteks and bought some "platinum matched" gold pin EH tubes from Upscale Audio because they’re basically the only 6922 they recommend for ARC gear. I have 4 Amprex 7308’s, but those I haven’t personally put on a tube tester and didn’t feel like sporting for four more at the moment. (I have 2 Willsenton integrated amps I’ve rolled tubes in and, well, don’t feel like spending more than the $400 I’ve already spent on those EH tubes).

@spatialking thank you. I have a guy who is pretty knowledgeable, and has some advanced test equipment. Appreciate the heads up.

I’ll update this thread when I hear ARC’s response. I know a lot of this classic gear (regardless of brand) from the 80’s and 90’s at least needs to be looked at because what sounds okay and what measurements show are probably two different things (for example, the DC offset was completely wack on my Aragon 4004, and that was after it had been serviced by the factory recommended repair shop...turns out it was a bad transistor).

Changing coupling caps isn’t modding if you are changing caps with the same values. I did that with my ARC LS5 Mk2 by an ARC authorised tech local to me. Changed the caps to TRT Dynamicaps which greatly improved the SQ.

Modding is when you change the value of the caps to something else or other components on the PCB or PSU to different values.

Ah, okay. Thanks.

Think I have settled on what I’m going to do.

On the LS-5 mkiii it looks there is 1 output cap and 2 bypass caps per channel. Going to upgrade each output cap to a Stealthcap and upgrade the bypass caps to Dynamicaps. (That will still be in the "voicing" that ARC uses since their REF stuff gets Stealthcaps and Dynamicaps are made by TRT as well).

Then I’ll let the tech replace anything else that is out of spec (I’ll ship to Pyramid Audio, who resurrected my D400 mkii, which ARC now calls "unserviceable").

@atlvalet  Look up Scott Frankland Associates in San Jose, CA

He just changed 16 Caps in my LS5 MKIII and it was worth every penny.

Sonic difference was Outstanding!

Thanks @djohn. Scott looks EXACTLY like the kinda guy I want tweaking my equipment.

Also, would love to see pics of the work in this thread and what exactly was replaced with what.

Glad to hear you feel the differences were noticeable.

@atlvalet For Audio Research and or any Tube Electronics, Scott Frankland is your kinda guy.

As a Heads Up, only Scott Frankland touches my Gear. He has totally Rebuilt my Classic 60 Amp which I have owned since New, and now the LS5 MKIII.

Call Scott since the LS5 MKIII is in the Rack, and it is not going anywhere right now :-).

Tell him David L. sent you.




As a long time LS5 II and III owner, who praised these models on here 20+ years ago, I would be hesitant to put a lot of money into this.  If it sounds good to you, then just run with it.  But if you're looking to put $1k into this, I would suggest you consider alternatives.

My line stage progress since then: ARC LS5 III --> BAT 31SE --> Aesthetix Callisto Sig --> Aria WV5XL which I have had for 15 years.  Each change was a significant step up with the last two being VERY significant refinements.  

After you hear these models and many others from Cary, Canary, VAC, it's hard to go back to the LS5 as it is just too unnaturally forward sounding and lacks the energy in the low end.  About 10 years ago I got an old Counterpoint SA-5 for a small apt system.  At that same time, a friend got a used LS5 II as he found a good deal and he knew of my praise of it years ago.  We ran them side by side and the LS5 lost to the SA5 in a flash.  Even his wife in another room asked what we did right when we switched to the SA-5.  He sold the LS5 and got an SA-5 and put money back into his pocket.  I am not pushing the SA-5, and surely you can do a lot better, but I am pointing out that there is so much out there so be careful what you spend on updates.

As for capacitors, here is a cool read: Capacitor Review Test


I would say that the signal cpas should be left alone, but power supply caps could be redone. In a tube pre these are few and even top of the line power supply caps are cheaper, better and will last longer than what we were using in the 1980s.

This is probably a much lower cost investment than I think you were considering.

The one exception here is perhaps the AC coupling caps typically used on the outputs should those prove to be leaky. 

@jafox sounds like you’re a huge Michael Elliott fan lol

I appreciate you giving me your pre-amp progression. Makes me want to search out an Aria Audio preamp, especially since they’re collectors items now (went down an Internet rabbit hole, and found this guy who may have gotten his hands on the last one: What did the Aria do the Aesthetix didn’t? (I ask because people seem to wax poetic about the Callipso). Someone should make a schematic of those Aria pieces because I don’t think any exist.

I guess a lot of what people love about the LS-5 is nostalgia, and nostalgia is a dirty liar. The reason I am thinking of getting work done to the LS-5 is that I think it will be cheaper in the short term to update it. Reason why is I have Vandersteen speakers, and that’s one of the default set ups with Vandies.

As @djohn mentioned, he’s very happy with the updates to his LS-5 from Scott Frankland. Per Scott, he upgraded 16 caps/etc that were (or might be) age related wear items. Scott did mention he didn’t touch the coupling caps and thought there could be further improvements there. Doing the same thing DJohn had done would be in the $1000 range.

@erik_squires reason I thought about coupling/bypass caps is because I think ARC offers (or at least used to) offer the TRT Stealthcaps as an upgrade and that would (at least in theory) preserve the ARC house sound.

You might join the Vandersteen owners forum, there are some there running 3A sig w variety of power / pre including Threshold, ARC, Aesthetix, Music Reference, etc….


@atlvalet the fellow that I purchased my LS5 MKIII from lived close to ARC, and also knew someone there. I had him deliver the Unit to ARC so they could check it out at my Cost and then ARC would Ship it to me.

I spoke to the Tech for the Condition of the Unit, and he told me the following.

1) Power Supply Caps will need to be Changed in 5 Years.

2) Rack Mount Faceplate (2 Holes per Side) was Extremely Rare since they did not produce many.

3) Stellar Condition.

The choice is yours if you wish to have this work performed. Your Unit is " Due " on the Power Supply Caps.

If you decide to have the work done, you might also want to look at obtaining some Amperex Holland Tubes. I tried the Russian Tubes initially, and when I tried the Amperex the LS5 really sang.

Scott Frankland is getting Older, so it is up to you whom you wish to perform the Service. After Scott’s work the Sonic Level of my Stereo was ramped up One or Two Notches. The $1K was mice nuts for the Sonic Improvement. Even the Better Half noticed.

@tecknik you are Absolutely Correct that the LS5 MKIII is Very Rare on the Open Market, and it took me 5 Years to find one.

@jafox I am not getting this in my System; " too unnaturally forward sounding and lacks the energy in the low end ". You are Correct that there is Always Better but at what Cost? I actually tried a Highly Regarded Pre since I was not sure if I wanted to Rebuild the LS5 MKIII. Once the decision was made and I received the LS5 back, within a short time the Highly Regarded Pre was Sold. I was that smitten with the Change of the LS5.

I am also getting Older, and I do love to read about Gear while Subscribing to 3 Mags. At my Age I do not wish to get on the Gear Merry Go Around. Trying the New Gear and if Disappointed, the Time and Monies lost pays for the Rebuild of the LS5 MKIII.

Case in point, I have been researching replacing my Classic 60 Amp which I have owned since New. After Months of Research, I do not have a Clue with what to replace it with. Have you seen the Price of the KT150 Tubes lately. I have decided recently that I should just stick with the Lowly 6550 Tube in the Classic 60.

The LS5 MKIII will very likely be my End Game Pre along with the Classic 60 if they do not Fail.


Honestly don't know the improvement possible there, you'd have to ask some one who has gone through it.  I was speaking from a generalized perspective focused on reliability.

Film caps have a much longer lifespan, and while they _may_ last indefinitely they do sometimes get leaky.  It's the power supply caps I worry about from a reliability perspective. 

If you think the sound quality improvements in the coupling caps worth it that's up to you, but I am afraid I can't offer you guidance. :)




@djohn It's interesting to hear of Scott Franklin's recommendation here.  I had the ARC SP-10 for 8 years before I switched to the LS5 II, and then the III some years later.

My final showdown with the SP-10 was the MFA Luminescence at a dealer in the mid 1980s.  I remember that session vividly.  The Lummi provided bass extension and authority but lacked much needed extension on the top.  The SP-10 did not at all have the bass authority or portrayed power in the lower mid, but the SP-10's dynamic contrasts were incredible.  The Lummi's strengths were the lower octaves, the SP-10's were in the upper octaves, but both lacked detail in the very top.  The Lummi was more laid back at the speakers with the SP-10 out into the room. I ultimately bought the SP-10, but the Lummi was special.

And then in the mid 90s, the final showdown for an update from the SP-10 was the LS5 II vs. the Sonic Frontiers SFL-2.  The differences were very much the same, and no was the same designers head to head again.  The LS5 did the 3D magic with greater ambiance, but it lacked the authoritative power of the SF.  Notice that I do not use the word, "better".  Both models improved from their older models in the previous shootout, but compromise was still high.  

All these years later, I felt that the forward presentation of the SP-10 and LS5 was not natural.  The ARC's forward presentation can be appealing and addicting, but after 15 years with the ARC products, once I heard a system with the sound back at the speakers and behind, and extended into the top octaves, there was no going back.  The 1980s Counterpoint SA-5 auditioned 10 years ago confirmed this.

Almost 30 years after the LS5's creation, so much refinement has come along where the compromises I have described above no longer need to be made.  If someone is willing to pay $2500ish for an LS5, and put another $1k into an update, there are just too many models available on the used market today at this price that offer a multitude of refinements.

Oh, and I used a Classic 60 loaned by a colleague for almost a year until I dropped in an ARC VT130 amp in the late 90s.  Wow, wow, wow, lovely.  Ahh, the good ol' days.


@jafox okay, now this is funny...because I have two differentially balanced preamps.

One is an LS-5 mkiii. The other is...wait for SFL-2 that's been updated by Parts Connexion and had the coupling caps replaced by the previous owner with VCap ODAMs bypassed by CuTF VCaps.

Now, I did a very brief listening test in a terrible room, and I couldn't hear any immediate differences...the LS-5 has EH gold pin 6922 tubes from Upscale Audio and the SFL-2 has some so-so regular EH tubes of unknown provenance with two Reflektors.

Anywho, if you were going to recommend a preamp in the $3500, what would it be? I ask because I am seriously considering sending the LS-5 to Scott F. I've read some reviews that state the mkii had "unatural" mid range bloom that was "fixed" by the mkiii version...but, you know...don't believe anything that you read on the Internet.

I'm also considering replacing the Solen caps in the power supply of the SFL-2 because I'm a tweaker and I can't leave well enough alone LOL

@atlvalet - It’s a small world indeed.

If you are using EH, Soviet, JJ, etc., tubes in your LS5, you have yet to hear its true potential. Do an internet search for the Tube dealer, Brent Jesse. He has given me sound advice on suggestions for several of my tube components over the years.

When I ran with the Aesthetix Callisto & Io models 15 years ago, a mix of Mullard, Telefunken, Amperex and RCA tubes made their way through these as I tried different pairs at each gain stage. Gutting out those horrid Sovtek’s was a major refinement.

I too am a tweaker.  I am a diehard tube roller as my many threads over the years can confirm.  And I recently fully rebuilt the massive crossover boards in a pair of Duntech Sovereigns.  That capacitor review page and other A'gon threads on Resistors steered me into the right directions.


Oh, I forgot to answer your question.  My consideration/audition list would include:

  1. BAT VK51SE
  2. BAT VK52SE
  3. Cary SLP-05
  4. Vac Renaissance Signature
  5. CAT SL-1 (Many variations)
  6. CJ Premier 16


@jafox - Absolutely Loved your writings and Thank You! for showing up to the Party.

I was also dead chuffed that you put up with the Classic 60 for a Year. My Classic 60 is very unique since Scott Frankland installed 2 Test Ports on Each Side, and 2 Bias Pots on each side of the Back Deck. I can Bias the Amp myself now with a Voltmeter since I was so sick and tired of lugging the Amp down to Scott's Shop.

I will certainly look at your consideration/audition List for the Pre's in the next little while. I did look at the ARC VT130 Amp that you mentioned and it will not work for me. I am also facing constraints with my Rack which I will not get rid of. When I look at potential replacements I also need to look at the visual & operational aspects, Width, Depth, and Height.

For my Amp replacement in the ARC Line, I love the Looks of the REF75SE but the constraint there is the Tubes. It is a Bigger Unit but it would work especially with the aspect of Biasing it from the Front which is a huge plus.

@atlvalet - I would suggest that if you are considering sending your LS5 to Scott Frankland that you ask Scott his Schedule to do the work. I had to reserve a spot and wait 3 Months. Just saying.

jafox " Nailed It " on the Tubes and also the Vendor to approach. When I switched from the Russian Tubes in the LS5 to these which were sourced from Brent Jessee if was like the LS5 " Woke Up ".

LS5 loves these;

6DJ8 Philips or Amperex, "A" frame top getter. Made in Holland.MATCHED PAIRS

New Old Stock original box. This "A" frame getter version is becoming increasingly scarce. These are all Heerlen Holland Amperex made, and labels are good to excellent. These are said to have lower microphonics, thanks to the heavy, rigid construction of the "A" frame getter support above the plates. These pairs are carefully matched for Gm and plate current within 1-2 percent. These have Amperex, Philips, Miniwatt, and other labels, all Amperex made. Grab a pair now! SINGLE TUBES ARE $40.00 EACH.

$85.00 per pair

In Stock


Thanks @djohn. I'll make sure I do that re: Scott.

Also, I went with the gold pin EH tubes because that's what Upscale has as their recommendation for the 6922 tubes on their site re: ARC equipment.

I will contact Brent Jesse about tube recs for the LS-5 and the SFL-2. I know that Chris Johnson recommends the Reflecktor tubes for the SF gear...but I'm interested to know what Brent says.

Appreciate the preamp reccos @jafox.