Ralph Mowery wrote:

When restoring the old tube equipment (tube receivers ) does it make any
difference if the old paper capacitors are replaced with the ceramic
disk or should another type be used ?

You are better off replacing them with plastic film capacitors, because
many of them are going to be of larger values where C0G ceramic disc capacitors
that can handle the voltage will be expensive and rare.

For smaller ones, such as in an IF strip, you would be fine replacing them
with C0G ceramics.

You don't want to be using high density ceramics.

I know for RF one needs to use capacitors that are rated for rf but in
the audio stages does it really matter what kind of capacitor is used as
long as it is the correct value ?

It does, because it has to fit and be stable and not fail. And in the case
of high density ceramics like Z3U types, they are very nonlinear which is
okay for supply decoupling but bad news for IF strips.

Reason for asking is that I bought an old receiver that someone has
replaced many of the capacitors. The book says pape capacitors for some
but they have been replaced by the ceramic disk type.

When was it done? If it was done sixty years ago, likely ceramics were the
only alternative you could get. And back then, high voltage NP0s were
available at your local tv repair supplier.
--scott

--
"C'est un Nagra. C'est suisse, et tres, tres precis."