Why did we move to oil filled Mylar from oil impregnated paper?

When truth be told we have been experiencing increasing problems with the failure rate of our paper in oil capacitors over the past 3 to 4 years, and despite a major research program into the causes of this increasing break down rate we have really come up with a blank. We suspect that the cause has to do with subtle changes in the chemistry of the paper, the oil or some other key part of the caps, possibly due to new environmental requirements imposed on the production of the paper, but who knows? Anyway, when it became obvious that we were unable to fully establish and rectify the cause, we decided to try Mylar. The initial experiments with oil impregnated Mylar were not sonically satisfactory, so we experimented with changing the construction to oil filled, the materials sealing the capacitor and the way we connect the foil ends to the lead out wires and voila! After some running in, the new Mylar/oil filled capacitors actually sound better in most respects than the previous generation of paper signal caps, the only real drawback is that they take nearly twice as long to run in and sound quite a bit worse than the old paper/oil type when they are new. So there you are, you don't get something for nothing!


As you can see from the above pictures, each of our signal capacitors is marked with a line on the right; this marks the start of the foil. It is our experience that the Audio Note (UK)™ capacitors perform best when the start of the foil is "facing" the incoming signal.

Our silver foil capacitors use a fine Mylar film instead of a paper in oil dielectric, which we have found to be the best compromise between sound and reliability. Those of you who have tried these copper encased silver foil signal capacitors can confirm the fact that the new Audio Note (UK)™ silver caps are better than anything else available, no mean feat when you also look at the prices.


The only possible improvement over the Audio Note (UK)™ silver signal capacitor is an interstage transformer, which removes the need for a coupling cap altogether!

Our specially made Mylar/oil caps have an immediacy, life, colour, lack of harshness and evenness of dynamic behaviour across the frequency range (or as we prefer to call it, the harmonic envelope), which is guaranteed to brighten up your day! Recommended as replacements in old and new valve amplifiers alike (and even in the odd transistor amplifier), and the finest possible choice for DIY projects.

In line with the best environmental standards, all Audio Note™ oil filled Mylar  capacitors contain only non-toxic, biodegradable vegetable oil. The Mylar dielectric enhances longevity and sound quality, to ensure optimum performance in all areas.


These capacitors are very heavy and should be mounted with suitable care to prevent the lead out wires breaking in transport.