Has anyone upgraded their preamp with V-caps?

I am interested in hearing about anyone's experience with upgrading their preamps with V-caps (in the output circuit). They are very expensive, i.e. 600.00 for two 2.0uF. I have heard that they are amazing caps and make a huge audio improvement, particularly in the bass and midrange.
YES. I have a highly modified (Robert H. Backert mod) Musical Design SP 2B Pre with 6922 output tubes. It's been a work in progress for the past several years. We just added the Teflon/Tin Foil V-Caps in the output stage and the results were nothing short of amazing- to an already world class sound, actually besting anything I have ever heard. I recommend the V-Cap addition very highly.
I'm asking this question myself. Why just the output stage?
Done a phono stage with TFTF v-caps. The best my ears have heard ... and then some.

For bigger caps (1.0 uF) I'd opt for th OIMP though.

Johnmcalpin, I've been told by a respected component designer that, for the preamp, the output stage caps are the most significant definer of the overall resulting sound and that this is where the new V-caps will show off their stuff...while the remaining caps outside of the output stage are usually in the power supply and will not change the overall sound...at least not to most peoples hearing. Of course, some sticklers may argue that point and want to replace them all. If money were no object than I suppose go for "all" the caps but, as I said, just the two output 2.0uf V-caps in my unit will run 600.00.
You have to be careful with V-Caps. True, they are the ultimate in transparency, but IMO at a cost of image density. I have put them in my AA Capitole mk II CDP and was amazed by the result for the first 3-4 weeks, but the longer I have listened, the more unsure I become. I belive that to make them work, the whole circuit design should be re-voiced.
Two questions, one for Pauly and one for Elberoth2

Pauly, I'm just curious...if the TFTF v-caps are the best you've ever heard, why would you use the less expensive OIMP for bigger caps?

Elberoth2, If you say that the V-caps sacrifice density, why would you suggest that the whole circuit should then be re-voiced with v-caps...wouldn't that exagerate more of the loss of image density that you experienced? Just curious. thanks
We've been using the V-Cap as an option for about the last year or year and a half. The Teflon part is one of the best coupling caps out there with no reservations.

If you don't like what you hear with this cap its because it is revealing a weakness! Frankly, the part has very little break-in (despite claims to the contrary, although you *do* hear the breaking-in and resettling of wiring disturbed during updates and newly-built pieces quite easily).

The part is very relaxed like a good paper and oil, but more detailed, with better bass and without the shelved highs that are paper and oil hallmarks. Overall very neutral and in a very good way. They are well worth the cost of admission (more so than fancy NOS tubes and a variety of tweaks).

Our preamp has a patented direct-coupled output balanced output and so avoids the classic issue of the output coupling cap (big cap=bad sound). So my comments are based on smaller parts, the biggest being 0.47 that we use in the phono section.

Thanks for the details. I was wondering about replacing all the caps or just upgrading those in the signal path.

I am aware of some possible downsides and will tread lightly.
I thought the OIMPs were the Top-of-the-Line?
Jppenn -> you are right. Using multiple V-Caps may have a cumulative effect on sound quality.

Atma -> I agree that you can DESIGN an excellent amp around V-Caps. Simple cap swapping is a different story.
Here is the v-cap web site. The TFTF's are the more expensive. http://www.v-cap.com/
I second Atmasphere's comments.

V-cap upgrades in my MP-3 pre and M-60 amps have improved the sound far more than any tube rolling (and I've tried many different tubes).

That said, even V-caps do not alter system sound nearly as much as a synergistic component (i.e.source/pre/amp/loudspeaker) change, but that's stating the obvious - I hope!
I might do this later this month. Bob Backert is once again working over my preamp. He did an astounding job last time and now he's adding a new power supply of his own design.

We talked about the V-Caps and he said they are a definite improvement, at least "10 percent."

We're going to add the power spply first and then see about the V-Caps. I might want the preamp back for a long listen before doing too much at once.
In your Musical design SP-2B preamp, what value of the V-Cap teflon did you use?
Currently, we use V-Caps in the phono stage of our preamp. Capacitors are still indispensable for the RIAA decoding process, so we make sure that high quality parts execute this delicate task. We have found that the Teflon V-Caps are one of the best two or three parts we have tested in this application. They give us a very accurate and detailed sound, with low coloration.

In our case, the V-Caps are connected in parallel (not in series) with the signal path, in order to maintain the direct coupling intact throughout the entire preamp. If only there was a way to eliminate these caps however, I wouldn't hesitate! For the moment, they have gained a place here.

Regarding the use of V-Caps for non-direct coupled preamps, I see no reason why they shouldn't represent a step above other capacitors (polypropylene, oil & paper, etc.) when used for interstage coupling. In this case, there is a compromise you must be aware of: The bigger the capacitor you use, the better bass you will obtain, but also the less transparency you will have. The optimal value will depend on the circuit's elements, but using less than 1 uF makes sense to me.

All in all, if you have the $$$, go get them.

Jppenn, I am reluctant to use > 1.0uf size V-Caps mainly due to cost. If cost was not an option I would use V-Caps exclusively.

Pauly, have you had a chance to try the relatively new Sonicap Platinum caps? They are a hybrid teflon cap and their cost is about half of the V-cap.


I just replaced .1uf REL/Audiocap TFT coupling caps in my Atma-Sphere MP-1 LS with V-Cap TFTF. With just a few hours break-in, it's surprising how much better the V-Caps are than the REL and how big a difference there can be between one teflon cap and another. Furthermore, this swap made a greater improvement than replacing oil/paper coupling caps in my amp that I know to be inferior to REL TFT-- confirming perhaps the critical importance of the preamp in the system.
I can't speak about the teflon v-cap in output stage application but would like to comment that replacing 2 x 3,3uF Mundorf silver/gold recently in my Omega DUOs tweeter XO made a huge improvement. Very costly upgrade but worth every penny imo.
Sherod, I have not heard Sonicaps. A couple of folks have recommended I try them.
Just a note to those thinking of making the change (which we think is very worthwhile)

Its a good idea not to change the value. Increasing the value to get more bass may cause the low frequency cutoff to go too low- lower than the power supply low frequency pole for example. This can result in low frequency instability or maybe just flabby bass.

Your 2nd best bet so far is the Mundorf, but if you are using the cap in an output section, consider that in due time most paper and oil parts will develop a small amount of electrical leakage, which can have disastrous effects on the bias of power tubes!

The following applies to all Teflon caps:

Don't try to cut it close on the voltage ratings. Our experiences with several Teflon types is that is asking for the cap to short! Leave plenty of leeway for the voltage rating, and don't forget that during warmup the voltages across the cap will be equal to the voltage of the unloaded power supply!

Finally, do not give the part a lot of handling. Teflon does not 'cure' like polystyrene and polypropylene, so handling the part can cause the dielectric to pull away from the ends of the parts, changing its value or even shorting it. Once in circuit they are fine.
Is that .1uf cap for the output coupling position?
It is .1uf in the LS and .47uf in the PS of my late model Atma MP-1 MkII. I believe Atma used other values in various vintages of this preamp. It sound f***ing great with the V-Caps.
This is a good thread; my suggestion would be to pay special attention to upgraded power supply anytime you are thinking improvement.

If you opt for a V-cap, do explore quality power supply.
Sherod, the output of the MP-1 is direct-coupled; the pair of 0.1uf caps (the unit is also differential) are between the voltage amplifier and the vacuum-tube output buffer.
Thank you Mr. Atmasphere. I have asked this next question in other threads and haven't received any answers yet: How does the Sonicap Platinum cap compare in sound to the V-Cap TFTF. I realize that the V-cap is almost twice the price, but is it twice as good? I am debating between the two for the outputs in my preamp which require 1uf or so. I have tried the V-cap OIMP and although it sounds very nice, it has a little too much warmth and roundness to the sound for my tastes in the preamp outputs.

You are getting into the age-old debate of diminishing returns. The first upgrade has better returns than investment, the next might, or might not provide the linear equilivant return from investment.

Now, you are asking, "is twice the price, 'worth it?'"

Yes, and no. You won't get twice the benefits.

Will you pay twice for, maybe....50% improvement?
I don't know Unclejeff. That is why I'm asking the question. You are answering my question with another question.

I've been surprised that the more I upgrade my system, the more audible becomes even very small changes. Small incremental changes can make large perceived differences in a high calibre system. Perhaps the Law of Diminishing Returns needs adjustment.

Another approach is to ask the hard question, does an audio system make the music sound real? However good a system, the answer will always be no. When making an upgrade the question becomes, how much closer does this upgrade take the system toward realism? If the system is already at 9/10s, a movement of .5 (or 50% of the remaining gap) is significant. I see the problem more in terms of Zeno's Paradox than the Law of Diminishing returns. And I bet this psychological need for unobtainium is at the root of most high-end buying. The psyche registers percentage improvement as percentage of remaining gap to be closed.
Sherod, IMO if you are going thru the trouble and expense of replacing the coupling caps, do yourself a favor and put the good stuff in. Its not that much more!
I agree Atmasphere. I might as well go for the best. Why take 2nd best for such a critical coupling position, right?
I totally agree with Atmasphere. Why put in 2nd best, save a few bucks and keep on wondering whow the sound would be if you would have installed the v-cap. Put your mind at ease, put in the v-caps and enjoy your music!
As I said earlier, the V-cap in my tweeter XO is magic and it will show you how much lesser caps, even Mundorf silver/gold do harm to the signal!