The SLP-05 Ultimate Upgrade

I saw that Cary is offering an upgrade package for the SLP-05.  I love this pre.  Stock as a rock, but with 6sn7w and RCA greyglass vt231.  Has anyone heard an upgraded SLP05 or might anyone have an opinion on the likely sonic result from the upgrades?


From Cary's site:

We have had numerous requests from customers for many years regarding possible upgrades to the SLP-05 preamplifier. For the past couple of years, we have made it a project to find the appropriate combination of components to take the SLP-05 to another level. Finally, we believe we have achieved our goal. We are incredibly happy with the results of these upgrades which can be installed in any SLP-05, no matter the vintage. The “Ultimate Upgrade” consists of changes to the power supply as well as the line stage circuit.

The power supply portion of the upgrade consists of “maxing out” the filtering capabilities along the entire power supply chain, all the way into and including the preamplifier. Purifying DC voltages is extremely important to providing a clean, clear, smooth sound quality that is free from grain, noise and strident artifacts. This also improves imaging qualities as it provides a much blacker background. The type and quantity of capacitance are important as we are not just adding an extra 1200uf of UCC electrolytic capacitance into the main B+ (high voltage) supply but also an additional total of 125uf of Polypropylene capacitors throughout the B+ line. This includes a huge 100uf Polypropylene capacitor right at the line stage PC board. The rest of the additional capacitors are used as bypass capacitors across each UCC electrolytic filter capacitor. This provides a dramatically smooth, sweet sound quality.
In the line stage circuit, we change the resistors to high quality 1% Vishay metal film plate load and cathode resistors. This parts change improves the midrange and bass substantially for a fuller, more textured midrange. You will notice more body and texture to vocals and acoustic instruments, etc. Bass is more authoritative and tight. Highs are smoother yet detailed.
And finally, for the pièce de résistance. We are removing all of the coupling capacitors and installing (10) Mundorf MCap coupling capacitors throughout the entire line section. This is the final addition that completely allows the sound qualities of the SLP-05 to shine through, resulting in a sweet, fluid, full bodied yet delicate delivery of every single instrument and natural vocal detail. It is done without adding brightness, and yet delivers an amazing amount of air and detail revealing the acoustics of the room and instruments with breathtaking natural realism. There is body, texture and fullness to instruments that break through with such ease and delicacy no matter the complexity of the music.
The “Ultimate Upgrade” is not just an upgrade. It elevates the SLP-05 to a whole other level of sound quality. It retains the attributes of the SLP-05 that you know and love but gives you more of everything.
The complete upgrade is priced at $1,595 which includes all parts, labor, and FREE shipping back to you. If you purchase a new SLP-05, you will be able to add this upgrade during the checkout process on


Many audiophiles remark about the SLP-05 as being one of the very best tubed pre-amps ever built.  I have not had an opportunity to listen to it.
Keep me posted. Happy Listening!
Yes I have heard this upgrade to the SLP-05 paired with a pass Xa-30.8.
I thought it did sound a little better than a stock one but It couldn't beat my Valvet Soulshine for overall tone,color,texture and most importantly transparency.I had the Janzen Valentina's at that time.

I have since moved on to the LTA MZ2S and couldn't be happier.The MZ2S is Offcourse a otl design and has no coupling capacitors at all,the output tubes are directly coupled and I use vt99's Tungsol with adapters instead of 6sn7's.The MZ2S rivals many high end SS preamps in the speed and transparency department with just the right amount of warmth,texture,liquidity,and holographic sound stage.

The only downside for me is having only remote volume and not input selection as well.

Best of luck to you,

I have not heard your preamp so cannot directly comment on it's sound vis-a-vis the upgrade. But I will say the upgrades outlined all make perfect sense and the price seems pretty fair for what you're getting in terms of parts quality and labor. Basically it's unlikely you could spend $1600 any other way that would be the same level of improvement as this upgrade.
It's a logical upgrade path but only after you rolled the the 6SN7 and GZ34 tubes first.
I am interested in this and glad to know... I enjoy my 05 and has been my staple for years now.
Thanks.  For me, the SLP05 is the best pre I've had.  Hits the right strings...I still remember actually getting goosebumps the first time I hooked it up.  Cary just started advertising this "Ultimate Upgrade," so it piqued my interest.  The only upgrade (other than tubes) I half considered was maybe having the volume control changed out at some point.

Sounds like a good thing, if it won't change the basic signature of the pre, as suggested by the Cary pitch.  Funny, though, some of the suggested improvements---removing stridency, improving smoothness and sweetness--aren't areas where I would think it needs improvement.  Of course, less noise anywhere is welcome, a little tighter, more authoritative bass would be nice, too.  Some of that, I think, has been addressed by the tubes.

@brf--absolutely.  settled in on RCA VT231s in the four main and blackbase 6sn7w in the balanced.  The new production EHX, imo, are the worst in the Carys...if that's all there was, I wouldn't have kept the SLP05.  Haven't touched the rectifier tube, though.

@kdude66. do you like the LTA more than the Cary and the Valvet?  if so, that's impressive, especially for its price!
I have compared Cary to Mac c500 and arc 5se and I still stuck with the 05.  I have switched to popes in the balanced section but kept EH in the other 4, I found this to have the best balance of bite and warmth so far.

im interested in your RCAs

will research further
The ARC Ref5 SE is certainly no slouch.  This model would be another "best of" tubed pre-amps ever built. Happy Listening!
I have had an SLP 05 for years and it replaced a Sonic Frontiers Line 3. I do plan to get the Cary upgrade done. I rolled every 6sn7 tube available including the rare metal based ones as well as the metal bottomed Russians and found the 6f8g's and the Marconi BL63 to be better sounding. I only used one pair of the BL 63 tubes as they do draw a little more current and I didn't want to create a problem. I hooked them up to the left of the headphone tubes. All the tubes I used were cryogenically treated. You will need to buy adapters to use these tubes but they are readily available.
Second on the ARC Ref5 being an incredible pre.  Different, but probably just as good or even better, depending on preferences.

@Iwin. If you do the Cary "Ultmate Upgrade," please report back.  I'll check into the adapters.

I'm a nut, but actually preferred the blackbase short glass 6sn7w to the metal base in the 05.

I suspect recommended tube combinations would be as numerous as SLP05 owners.  Some folks like the EH.  Some folks like some of the new Chinese ones enough to drill out the holes to fit.

@joey_v .  At least for me, changing the balanced tubes when using xlr made the biggest difference.  The popes are probably about the only tubes I haven't tried.
My SLP 05 is due at Cary Friday 11,2017. Once I get it back I will post my impressions of the upgrade.
I look forward to it lwin

I’d been experiencing direct current to my left channel, so I’ve had my SLP-05 shelved for many months. Sent it off to be examined and sold, but then this opportunity popped up. Hopeful that the capacitor replacement will take care of whatever it was that I was getting. Been using an SLP-98, which is nice, but quite a step down. I won’t be able to offer valid comparisons beyond what will hopefully be a giant leap over the SLP-98 (306SACD Pro, Focal Diablo Utopia Speakers).

My SA-200.2 is also in the shop. Excessive input noise. Supposedly, they are dead quiet now that some supplier changes have been made.

Hope to get both back by end of month. - Josh

just FYI, look into replacing that 306 sacd.  I had it and the ones available nowadays are quite a step up.  Hard to believe as I am a Cary fan.
Thanks, joey_v

I follow the digital front end market and I'd expect that any 2008 design will be bested by today's hi-end standard. If I can sell my 306 SACD and SLP-98, then maybe I could get into the market for PS Audio's twin chassis SACD player (at a big discount from MSRP). - Josh

I have a slp-05 and was wondering what you think of your unit's performance post upgrade?  Did Cary also adjust the pots for your phase gain tubes to optimally match them during the upgrade?
I'd be interested in upgrade results too.
FWIW, my former Cary SLI-80, current SLP-98 preamp, and V-12R tube amplifier have upgrades done by a local tech but following recommendations from Cary + some extras. After tube rolling and interconnects, in every case I found these internal parts and mod upgrades to be worthwhile for sure in my particular system.  Now going for a 2nd upgrade in the V-12R using the newer Mundorf Mcap Supreme EVO Silver/Gold Cary is using more so lately. If the SLP-05 upgrade is anything comparable, seems like a great option to try vs buying yet another preamp to try and replace it with.  Interested in hearing how it goes for ya, give it break in time too when you get it back!  
I am still waiting for Cary to send my preamp back.  There were a couple unexpected delays. Even though I exchanged several emails about the upgrade they sat on it for a week before sending me another email asking as to why I sent it in! Another week went by and I was told they needed my tubes to dial it in. When I got the email, I was working out of state for a few days but I sent them priority mail last Thursday. They said all the new parts were installed so I hope they send it back to me this week and I promise to post my impressions within a week of receiving it.

Hope you get it back soon.  The upgrade details on the Cary site sure sounds like it has the potential for a significant improvement in listening enjoyment.

And with your tubes they will fine tune their gain to closely match the phase gain tubes to with 0.1 to 0.2 db, which is probably much closer than tube seller selection matching.  That should optimize sound stage balance and imaging.  Together with the upgrade your SLP-05 should be "Born-again". 
I got an email from Steve Witek of Cary yesterday. Everything is set. They let it burn in with my tubes over night. I encouraged them to listen to the preamp with the tubes I use as they are a little exotic. They are going to listen to it today & then send it back. I will be traveling again at the end of the week so I probably won't be able to get some good listening time until next week but I will post my impressions asap. Larry

Excited for a review of the upgrade.

Iwin, what 6f8gs do you recommend?

I am very interested in your impression of the upgrade.
I have been considering doing it for some time now.
Let me throw in a little Cary bashing.  I had an SLP-05 i bought used on Agon.  When i started listening something seemed off and felt it might have been out of phase.  I did extensive trouble shooting and isolated the problem to the Cary. I sent it back to them (at my expense of course).  After their testing,  they found they had wired it incorrectly and was indeed out of phase.  They charged me for the repair plus return shipping despite my protests that this was their fault even though the unit was out of warranty.   Needless to say I will never buy anything from Cary again. 
@lxgreen That is really disturbing considering it was their fault in the first place. I really would have expected much better service from them. It really should have been repaired gratis. I don’t understand companies that won’t step up to do the right thing and risk the bad mouthing that is certainly going to follow on all these forums. The cost to fix it, to them, is so little compared to the negative press and loss of future sales from potential new owners. What a great story it would have been if you reported they fixed it for free, so many people here would be looking very favorably on them. Their short shortsightedness just created the exact opposite impression.

Shredder it has been years since I auditioned 6f8g's so I will have to wait for my preamp to come back to let you know what I finally liked the best. I think it is either Kenrad or Sylvania and I auditioned National Union as well.I like the Marconi BL 63 tubes the best but I was leery of using more than 1 pair as they draw a little more current. I thought Cary would tell me the BL 63 tubes were a little too much for the preamp.  If I had known that the Cary could handle them I would have sent in only the BL 63 tubes as they are in another league .

If you are buying adapters pay a little more for the quality ones with a metal base that is slotted along the side for the tube cap wire. The cheap plastic adapters don't have a slot and  with the wire outside the body can be a very tight fit in the tube socket.

Thank you! lxgreen for sharing your story.
it is imperative that we all post both positive and negative experiences when dealing w/ these companies. Same for dealers/retailers as well.
In your case, it was certainly Cary's fault. Hope youn wrote a letter (not an email) to the CEO.
What brand(s) do you use now?
Happy Listening!

So, Iwin, how does it sound? Anyone else heard the upgrade?


OK after a couple glitches with one of my amps not powering up & one preamp tube suffering the travel; I finally got my system running properly 2 days ago. It is still breaking in but I like what I am hearing.

Let me back up a little before I get into the nuts and bolts. I have looked at other upgrades for this preamp but my concern is the voicing. In my opinion Cary has a house sound whether it is their tube or solid state gear. Going to a third party might change the Cary sound that I like so much that  I never did try a third party. When Cary announced the upgrade, I was delighted. It is one thing to plug in parts and maybe measure performance but you also have to listen to what you did. I trust Cary to do this and they delivered.

The upgraded unit has deeper and more accurate bass. The width and depth of the soundstage increased. On the top end properly recorded cymbals sound exactly as they should with no smearing. Vocals are spot on. Every recording I listened to was better.

My preamp was about 10 years old and the technician replaced a bad resister. Also the upgrade includes new capacitors. Capacitors have a life span. What I am driving at is if your preamp has some years on it ,you are going to have it completely checked out as part of the upgrade. The way I look at , my preamp sounds better and it should be good for another 10 years.

Some of you probably want me to quantify the improvement but as I said it is still breaking in. I am happy with what I am hearing and I think for me it was definitely worth the investment. You may disagree especially when companies like PS Audio are giving away wonderful software upgrades for their equipment.

Shredder , the 6f8g tubes I settled on were the Kenrads. For those of you not familiar with these tubes, they were the precursors to the 6sn7 tubes. I hope this write-up proves useful to you . Larry W

Great that your hearing a definite improvement and that should get even better as the new caps break in as well as the preamp overall. And as I started earlier its very unlikely you could have spent $1600 any other way and gotten the same improvement so well done!
Iwin..fabulous info..thanks
Thanks so much Iwin, very helpful. I am going to do it. Mine is also 10 years old, at a minimum, it probably needs a little tune up.
Hi All,

So I too went ahead and had my 8+ year old SLP05 ugraded.  Got it back yesterday along with a set of (6) RCA tubes from Cary.  Tubes were matched on selection and then adjusted prior to initial burn-in check at Cary Audio to optimize gain match.

I am currently running it in using standard fuses and my emergency backup jj rectifier rather than my NOS Mullard.  Also have my Golden Ear sevens hooked up during this run in rather than my Harbeth SHL5+ speakers.  So the sound may not be optimized for my tastes yet.  FYI, my system chain is a music-dedicated MBPro running JRiver MC21 > ISO  Regen with LPS-1 power supply > PS Audio DS DAC > SLP-05 > Pass XA-30.5 amp.  Running fully balanced from DAC to amp.

Of course I have l Listened a while to get a quick first impression of the sound.  And I must say that I am impressed and extremely pleased with what I am hearing.  Even with a few second string components in place the sound is much better than it was previously with my regular lineup.  I would echo the description by Iwin.  Immediately obvious was the lack of speaker hiss.  Much more quiet than before even though I then had in a new set of Sophia Electric 6SN7s which I have found to be the quietest tubes of all the many that I have tried.  Of course a little of the other sound attributes I'm hearing may be due to the new set of RCA tubes,  but considering that I have tried eight other sets of NOS tubes along with four sets of new production ones, I think I have a reasonable feel for what the preamp upgrade brings to the party.

Therefore, in no particular order, these are the "improvements" I hear over the original SLP05:
          1.  Deeper, tighter and more impactfull bottom end.
          2.  Soundstage is somewhat deeper and wider with great image specificity and stability.
          3.  Tone density improved while maintaining transparency of individual instruments.
          4.  Very smooth, organic sound yet with excellent dynamics. 
          5.  And most pleasingly noted by me is the sound wave impact and decay which is now much closer to that heard in a live performance.  That is to say the notes now start and stop faster which is so much more realistic to me.  Not sure what is the reason for this effect.  Maybe added capacitance, type of resistors used or changes in power supply.  All I know is that I really like what hearing. Percussion whacks are now really exciting.

Hope to hear a bit more improvement over time and with my normal configuration.  I will look forward to hearing others impressions.


This goes out to Iwin & Nanotweeter.  Thank you for your first impressions...I would imagine that all would sound better from this upgrade.  My concern has to do with the Bass, or Bass output or intensity.  My system is very Bass sensitive basically because of my room and not having the speakers In their ideal position. 

So my fear is that any additional energy or bass volume could bring about bloat...while tighter more accurate bass could be  welcome.

Example.. I have tried  numerous amps with the slp-05 settling
 on the Esoteric A-03 which IMO is a great match provided you have pretty efficient speakers.  I Had A Krell EVO 300 which sounded nice but way to much bass energy for my rig.

My other concern is that with all my system changes it is very rare to experience replacing a component without having to tweak other parts of system.  AND I really do not want to get back into that since I have reached a really good place with system synergy...

Any Thoughts on my concerns would be greatly appreciated

Thank You


Hi Tony: If you are happy with the way your system sounds: I would not change it. With the upgrade you are going to get more bass and it will be more accurate but it may be too much for your preferences. You are also correct in stating about changes to your system requiring tweaking; I am going through that now as I am moving my speakers around to get a better balance and I might have to turn down my subwoofer a notch or two. Best wishes: Larry W/lwin
did Cary replace any caps or resistors etc, in your unit along with other power supply and circuit changes?

In both cases after my upgrades with other type Cary units, I noticed both sounded decent when I first got the units back and played the first day or two, however sound improved again to a new level once I got more than 100hrs on them, like another veil lifted off, things settling in.   
Yes to both decooney. If you go back to the original post you will see what they do as part of the upgrade. You can also go to the website to get additional information. Larry W /lwin
Well, my upgrade has been completed and Cary is finishing up some testing and burning it all in. It will ship Monday and should be back to me in Colorado by Friday. I will post my thoughts after I have a chance to further burn it in and give it some serious listening.

BTW, I have experienced great customer service. Dan Wemmer, in particular, has been very responsive to my many questions. The upgrade was finished very quickly.

More later.
Hi Shredder we look forward to hearing your impressions. I also found Dan to be great to deal with. I got the impression that the SLP-05 upgrade was his baby.
Thank you Iwin...I will continue to check out what people are saying. Maybe I'll convey my concerns to Cary as well.  Perhaps a partial upgrade like just the caps and some power supply work might be a better solution for me.

Hi Shredder,

Any News to report ???


Hey. It has taken quite a while to break in.

My experience mirrors Iwin and Nonotweeter's. The DAC is basically better sounding in all respects, just more of a great thing. In particular, it is quite, has better separation between instruments and vocals, greater tonal density/richer sound, and much deeper tighter impactful bass. More than worth the cost.
I mean the pre is better.....................
For those who've done the upgrade, does it still sound like a Cary SLP-05, just better?  I haven't sent mine in.  My biggest concern is doing the upgrade and it sounding like something else and losing what I think is wonderful about the SLP05.
stfoth  It sounds like the Cary SLP-05  on steroids. You have that nice Cary sound but with more details such as bass and separation between instruments. The sound stage is larger, side to side as well as deeper.
I've had mine back for about a week now and it has really come alive after a full week of burn in.  I second Shredder and Lwin's experience with the upgrade, worth every penny.  Besides the sonic improvements my system is now dead quiet which is absolutely wonderful. 
 Both Steve and Dan at Cary were fantastic to work with, the whole process took one week and it was on it's way back to me. Very pleased with the entire process, it's nice working with people that enjoy that they do.
HA GUYS, I just got the slp-05 ult. but the big  volume only turns up to about 2 oclock, with the remote, there is a binding at that point ,if i turn it by hand there is a click then it will turn to a higher volume point , are they all like this
@smokenjo that is not normal.  It should travel the full range using the remote
Sounds like your LED wires from the volume knob are catching as the knob turns.  If you take the bottom off the unit you will see the LED knob wires that come from the knob.  Just move the wires a bit so they don't catch on the ALPs pot as it turns.  Of course turn the unit off before you do this.
thanks, hogweed75, i called CARY  and talked to DARYL, MY SALES REP.  he talked to their tech and he  had said the same thing with the wire, but nothing about opening the bottom of the unit but did say to turn the knob slowly back an fourth to see if it will free it self