I'd be cautious about Jupiter caps in a warm tube amp. They're rated only to 110F(43C), as compared to 65C for most oil caps, and 85C for many non-oil constructions. If they develop DC leakage due to heat you may have circuit problems long before seeing evidence of melting.
There have been reports of Jensen PIO and Mundorf SIO (rated to 65C) failing in hot chassis, so be careful. Partly for this reason I use non-oil constructions like Mundorf Silver/Gold and V-Cap teflon.
There have been reports of Jensen PIO and Mundorf SIO (rated to 65C) failing in hot chassis, so be careful. Partly for this reason I use non-oil constructions like Mundorf Silver/Gold and V-Cap teflon.