Boutique caps in oil... reliable?

The only oil caps that I’ve seen leak (I’m sure there are others) was Jensen oil caps. The Jensen copper foil paper and oil were notorious for leaking within 5-10 years. I never really cared for their sound anyway but after replacing one after another for people I definitely wouldn’t recommend them. Some leaked within 2 years.
V-Caps are amazing and never seen a problem with them. I’ve also seen most Vitamin Q caps still working even at 15-20 years. Not that they sound great but they are good cheap oil caps.
Of course it’s all about the cost you want to put into equipment and sound taste.

We've sampled a number of oil filled caps over the years. I've not seen a type that didn't develop electrical leakage, although I'm sure they exist.

Electrical leakage is where the cap takes on some of the properties of a resistor- a voltage can be dropped across it. If a cap with this problem is placed in a circuit driving a tube or transistor, the voltage that will show up at its output will affect the operating point of the active device.

If that active device happens to be a power tube it could overheat and be damaged. It'd be a real shame if that was a $1200 211 or some such! In a loudspeaker this is likely of no consequence.

Being an OTL manufacturer we had to demonstrate that our amps were really reliable, since the Futterman and other amps prior to our showing up hadn't been so good in this department. So we had the nearly Sisyphean task of convincing the market that OTLs could be as reliable as any other amp. For that reason we simple didn't and don't use oil filled caps.

How about foil paper & wax capacitors Ralph?  Have you seen problems with capacitors using wax? 

I believe you use V-caps which are foil and fluoropolymer film so I assume you do not have problems with them.  I also noticed VH Audio makes an oil impregnated metallized polypropylene film capacitor, that they market as,  “one of the most transparent and musical oil capacitors ever made.”

@atmasphere

Thanks for your perspective. My current needs are as line level high pass filters, so even if there was DC leakage I don’t think I’d care.

I’m a little curious though, is oil-filled the same as oil impregnated?

When I think of oil-filled, I think of big cans from the old days.