[R-390] Those orangey capacitors

[Tisha Hayes]

There is an entire mystique attached to the orange drops but there need not
be. The caps we are really talking about are the Vishay Sprague (SBE)
"orange drops" that actually come in a couple of different varieties;

The three major models of orange drop are the 225P, 715P, 716P and 6PS
series.

225P are polyester            (in a flatter package than the 418P)
715P are polypropylene
716P are polypropylene     (in a flatter package than the 715P, tinned
copper leads)
6PS are  polyester
418P are polyester

There are no-name clones that try to capitalize on the orange color. On
eBay you may find that color difference means that a capacitor costs ten
times more than normal.

There are differing opinions on the audio quality of amplifiers with
different capacitors. Some say that polyester caps sound better. Other
subjective terms like "brightness", "organic" or "fuller" sound.
Remembering that many of these are used in guitar amplifiers and really
those devices are not renowned for spectral purity. In fact some guitar
amps intentionally add distortion to sound as part of the effect

So much of the hype about orange drops comes from the audiophile world.
While there are maybe a half dozen caps in the AF chain that might have
some impact upon audio quality for most other places in the R-390A a good
ceramic disk works just fine. There are so many other factors that affect
audio quality such as the amplifier tube, speaker/ headphone or how where
you have the IF gain set to.

Probably the biggest challenge any of us will face is trying to pack a
bunch of 600 volt orange drops into the tiny spaces under the IF deck.

-- 
Ms. Tisha Hayes/ AA4HA

"Objective considerations of contemporary phenomena compel the conclusion
that success or failure in competitive activities exhibits no tendency to
be commensurate with innate capacity, but that a considerable element of
the unpredictable must invariably be taken into account." -- George Orwell