[R-390] Replacement Capacitors

[Charles P. Steinmetz]

Gordon wrote:

>If the main concern is C-553 shorting and taking out the Filters, 
>why wouldn't it be wiser to put a pair of .02 in series for extra 
>safety in place of the one .01 ?

No reason not to, and it could extend the MTBF if one cap had an 
early failure.  Of course, you wouldn't know that one had failed, so 
the end result (when the second one failed) would be the same -- one 
or more open filters.  But any good-quality film-and-foil capacitor 
bought new today is very likely to outlast you and the next five 
owners of the radio, at the least.

Lee wrote:

>Some of what you are reading is nothing more then bias.

Since I'm the one asserting the superiority of film-and-foil caps in 
tube equipment this time around, I presume you are referring to my 
comments.  My view is based on decades of observation of failure 
modes and rates of capacitors in manufactured tube products, and 
follow-up testing of hundreds of new capacitors made by reputable 
manufacturers obtained through the primary supply chain.  So call it 
bias if you want to, but if so it is bias based on a lot of objective 
observation and testing.

Tisha wrote:

>So much of the hype about orange drops comes from the audiophile world.

There may be a preference for ODs among some audiophiles because of 
their perceived sonic characteristics, but that has nothing to do 
with the reason I'm advocating using film-and-foil caps rather than 
metallized-film caps in tube equipment.  The reason for the latter is 
reliability, due to the inherent nature of metallized-film caps.

Best regards,

Charles