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