The best coupling caps in power amp ?? Mundorf, Infinicap ??

I am interested in some of the results of coupling cap modifications in quality tube amplifiers that you have first hand experience  with......Mundorf, Infini-Caps, Wonder-Caps ???       autospec
Mundorf are excellent caps.  M-cap supreme, great in midrange, very rounded sound.  The silver has better clarity, more tranparent.  The infini-caps are neutral, kind of forward sounding.  Very analytical sounding caps, nothing really interesting about it.   Go with Mundorf caps, you will be happy with it. 
I placed Jupiter copper foil caps in my 300b SET (replacing the stock Solens) and it's a worthwhile upgrade.  I went with them rather than the Duelund CAST due to the lower cost and enthusiastic recommendations. 

The Duelund CAST is superb in my DAC  and speaker  crossover (tweeter).  Though expensive I believe they are definitely worth their cost. 
I would agree with your assessment of the Infini-caps, but I have some interest in maybe using Mundorfs.....I think I will read on about other experiences
Two very experienced modifiers on this site Grannyring and salectric seen to prefer the Jupiter copper foil compared with the Mundorfs. 
If price is not an issue then i would go with the jupiter copper foil.   That is comparing the Mundorf and Jupitor.  If space permits, i would get the Duelund cast hybrid.  
Thanks Charles.........I'll go in and check out the Junipers (copper)
Haven't yet tried the Duelund or Jupiter copper foils, but oh I so want to.

I would try Clarity CMR for the most neutral and high value.

I have issues with the fanciest Mundorf Supreme's. THey tend to scintillate, or hype up the mid to treble. It's not unpleasant, but to my ears far from neutral.

Mundorf MKP's are real steals and great for low level detail when you also need a noticeably dark cap.

Of course, check the physical sizes before you buy anything! :)


Do your homework, as you’ll find that one or two expensive "boutique" caps mentioned are very likely just re-branded Solens (which are far cheaper) compare diameter/length/lead length for the same uF and voltage and you will see why.

Cheers George
Do your homework, as you’ll find that one or two expensive "boutique" caps mentioned are very likely just re-branded Solens (which are far cheaper) compare diameter/length/lead length for the same uF and voltage and you will see why.

Cheers George
If you know which boutique company just re brands Solen caps, why not name them?

I suspect you have been out of touch with the boutique cap market for a few years.  InfiniCaps (and WonderCaps before them) are quite dated and no longer in the running for a high quality coupling cap, IMO.  The regular Mundorf Supreme is a fairly inexpensive cap that I like a lot but some people will find it too colored.  It is a very warm and slightly opaque sound but very musical and very dynamic.  The more expensive Mundorfs like the Silver, Silver/Oil and Silver/Gold/Oil all offer a more extended high-frequency response with more detail and more transparency, but the tonal balance is not as natural to my ears as the standard Supreme.

If your budget has a bit more room, my very favorite coupling cap is the Copper V-Cap (CuTF).  It has the best combination of sound qualities of any coupling cap I have tried, and it excels in the areas that are most important to me: neutral tonal balance, excellent detail and excellent dynamics.  Out of the 20+ coupling caps I have tried over the years, this is my favorite.  Some folks prefer the Duelund CAST to the V-Caps, but I consistently prefer the V-Caps (either TFTF or CuTF versions). 

I have not tried the Jupiter copper foils (contrary to Charles' post above) but they also have their fans.   
I would agree with all that has been said regarding great choices. I like the Jupiter copper foil in wax caps quite a lot. Jupiter and Duelund make their own caps in house and both sound just fanastic. 
I can’t disagree with salectric’s point, it boils down to personal preferences and that will never change. I haven’t used the V Cap copper but have experience with their Teflon tin foil  and OIMP capacitors. We all simply hear what we hear. I could see where someone would categorize the Teflon V Cap as more ideally neutral and a preferred choice depending on the particular component, system character and objectives.

Jupiter and Duelund CAST are beautifully "natural"/organic in character/tone and this is what I find most important and desirable. It depends on what a listener prioritizes, no right or wrong. There’s a capacitor available that will suit a given taste once one determines what specific sound they’re seeking. Plenty of good choices.
Thanks Charles; I have used some of the V-caps with good success, but I can't buy every cap out there and the in put from other people is the food for thought to try others ............Some of the Russian silver mica's  have great sound, which I have also used........autospec
I am also a big fan of the V-Caps.  I used them in the components I build.  I will be trying out the copper Duelands soon in my DAC so stay tuned.  Briefly tried the Jupiter but felt they were just OK but I never really let them burn in so take that into consideration.  Happy Listening.
Hi Bigkidz, 
Impossible to predict if you'll prefer the Duelund CAST vs VCAP, too many variables involved.  I do have a favorable bias toward the Copper CAST,  I just find them sublime "in my system ": 😊
If you know which boutique company just re brands Solen caps, why not name them?
Like I said do your homework, it’s not that hard they all have spec sheets.
The mods would have a field day, with me being a manufacturer if I named someone.
Look it up for yourself, then you to will think twice, paying ten times more for the same cap.

compare diameter/length/lead length for the same uF and voltage

Cheers George
The difference between Duelund CAST and Jupiter copper is this. I have used both in crossovers, tube amps, preamps, hybrid amps and dacs so I think I have had good experience with them both. You must let them break in for at least 150 hours to know how they really sound. This is a must. 

The CAST caps are a tad more tipped up in the upper mids. Some may like this as it sounds very resolving and open. For me this slightly tipped up upper mids caused my tinnitus to flare up. It was a tad too aggressive for me. I found this tendency when used in electronics, not in passive speaker crossovers. In crossovers they are magic. The Juputer caps have more top end air, improved Micro details, and an obvious improvement in bass impact. The Jupiter caps are far less expensive to boot. They seem to work better for coupling and output in tube amps and dacs. 

I have had  less experience with Vcaps, but one the one occasion I tried them they did not offer the "meat in the bones" weight and tone of the CAST or Jupiter caps. Crazy resolving however. 
Duelund’s Cast-PIO-Cu caps ARE more resolving and open, than any that I’ve tried over the years. I don’t want to hear anything but the original music and venue, without any editorializing. Duelunds are just less, "there" and allow me to hear further into whatever’s on my recording. I’ve had four in my Cary SLM-100 monoblocks, for a few years. btw: Some say that foil orientation doesn’t matter with stacked caps. Testing for noise proves otherwise.
I too just replaced the coupling caps in my 300b Audion with the Jupiter Copper caps and the results were excellent. Very Surprising the improvement.
It's interesting to note that when proponents of the VCap describe its character the word is neutral. 
Duelund CAST proponents descriptive word is natural.  Both are meant to be complimentary yet they convey perceptive differences. Having used both capacitors I understand the chosen terms. Natural is the highest compliment I can use to describe an audio product. 
I have built more tube amps that most people have seen.......I have used 20-30 different caps over the years......I have always been interested in the descriptions people give of there sound experience when dealing with different sounds , speakers and delivery of sounds.......I try and use this information in the construction and delivery of tube amplifiers.....I try to understand the descriptions people give for different sound quality in words that differ from one to another when describing the same sound ......When one person says "warm" and they are using a V-cap another may use a totally different word to describe their experience ......autospec
YEP, "variables"!    Semantics, perceptions, systems, aural acuities, references(if any), etc.   Of course, the better(to me, more neutral/transparent/clean/natural/quiet/fast) ANYTHING(tubes/rectifiers/caps/cables/special copper/silver) swapped into the total system, the more obvious strengths OR weaknesses upstream will become.   The natural tendency(for most) would be to attribute whatever perceived differences might be exposed, to the new component(s).       "Best" will always be subjective.   
We've been auditioning coupling capacitors for close to 40 years now. The current king is the V-Cap copper foil Teflon; it is both neutral and extremely musical.

As far as musical goes we've heard some extremely good paper and oil types but the problem we've seen with many of them is that they can develop electrical leakage. Usually this is a very small value, but when you are using the coupling cap in a power amplifier section the effects on the bias on the power tubes should be considered!

For this reason I don't regard such caps as in the running as some power tubes can be quite rare (not to mention some vintage power transformers in some vintage amps) and such parts could shorten the life of both.  So I see the V-Caps as being the only game in town.

Now one important issue with the V-Caps is that being made of Teflon they should be handled as little as possible. For this reason they are shipped in bubble wrap and they really should not be unwrapped until installation. Otherwise the handling will cause them to change value and by this I mean loose value. I don't doubt that this issue alone could be the reason why the well-deserved accolades this part gets are not universal. But that's how it is with Teflon caps.

So you mean the caps are easy to mechanically deform? For instance, squeezing them along the length?

Never handled a cap that delicate!

No; but if you've handled a Teflon cap, then unless it was hermetically sealed you probably changed its value. You won't see much in the way of physical deformation though.
I've never seen any film cap that wasn't hermetically sealed. This is very weird.

I mean, if not sealed, then really any change in atmospheric pressure or humidity could change it's value over time.

I have been in touch with Chris over at V-Cap and it seems I am somewhat corrected. Turns out hermetically sealed caps are more rare than I thought, but that still doesn't make them subject to atmospheric effects like I had surmised.

I hope he will post here shortly.


Just to be clear, the usual handling of a Teflon cap required to install it has not resulting in a change in value in the 20 years we've been using them (prior to using V-Caps we had Teflon caps made for us). So this is far less of an issue than I probably made it look.

Regardless of brand, who has experience mechanically dampening and securing caps to a board? I recently used blue tak to secure my mudorf coupling caps in my rogue m180s and I swear they sound better. Anyone else experience this? 

I apologize for the late reply. Atmasphere is correct, as it relates to many capacitors that used 'teflon' film… before V-Caps were introduced in 2004.


The TFTF or CuTF series V-Caps don’t change capacitance, and aren't deformed or damaged with normal handling. I've tested both smaller values as well as larger values (up to 3.3 uF) as if squeezing a lemon, or pinching a grape, while measuring on a Quadtech LCR 1920, Quadtech 7600+, and GenRad 1689M. The capacitance measurements, as well as the DF and ESR measurements don't change beyond the testing equipment’s +/- accuracy range.


Where you MAY run into a problem (with any film capacitor) is when an installer gets overly aggressive with a nylon cinch tie. A great deal of force can be exerted over a very small area, and the square 'box' portion of the nylon cinch can make contact with the central body of the cap. The square corners of this box can penetrate the skin of a capacitor, and cause a short. Also, I've seen instances where small material on the surface of the cap gets driven through the outer skin... 


I recommend cinch ties be used at each end of a capacitor winding, where penetration of the cinch tie of the outer skin isn't likely to cause a short, because it is at the cap's ‘margin’.


The reason V-Caps are wrapped in bubble wrap, is to:


1) protect from shipping damage. Anyone who’s done business with VH Audio, knows I have a tendency to ‘overpack’ ; -)

2) protect the solid core leads from getting bent acutely

3) prevent a sharp edge from one of the cap's solid core leads from penetrating the winding of another cap, during drop-kick exercise by UPS:

4) I use bubble wrap to help ‘pair’ caps when customers and OEM’s want matched pairs.


I'd also like to mention that a true ‘hermetically sealed’ cap is encased in a (usually) metal/glass/ceramic enclosure and must use a special hermetic seal with bare (uninsulated) metal lead material. No other type of capacitor is truly hermetically sealed, in the strictest sense, which would also protect against immersion in liquid. The OIMP V-Cap series is a truly hermetically sealed capacitor. However, in a practical sense, modern capacitors are usually 'sealed' quite well...


Long term changes due to Atmospheric pressure is not likely. I have copper and tin capacitor standards/prototypes that were built >13 years ago, and the capacitance, DF and ESR hasn't changed for those samples, at least not within the tolerance of my measuring equipment, which is far more accurate than typical equipment used in most capacitor production facilities... 


Lastly, regarding mechanically dampening and securing caps to the board, there are many methods that can be successfully used for this, including 3M double sided tape, nylon cinch ties (when used correctly, and not overtightened), and nylon cable clamps (like this: To provide additional mechanical dampening, you can use silicone stretch seal tape (found at any Home Depot) to provide a nice ‘bed’ for the capacitor, and protect it from sharp edges that might be found on underside of circuit boards.

Best regards,


Chris VenHaus