wrote in message
oups.com...
On Jul 11, 5:13 am, dadaderk wrote:

I only did some minor modifications in the beginning (I bridged and
replaced
some capacitors). First time I put the power on in a room where it was
very cold and the GZ34 went.

I hope I am not understanding you correctly... "I bridged and replaced
some capacitors)... One should _NEVER_ bridge a cap if the goal is to
replace a cap that has failed. The old cap *MUST* be removed from the
circuit and the new cap put in its place.

If the goal is to add additional capacitance, it is much better
practice to remove the 'small' cap and replace it with a new 'larger'
cap. First, after 20 years the existing electrolytics may be tired,
and second, modern caps are typically much smaller than their older
cousins such that space is not an issue. Parallel caps _of the same
type and value_ *are* a legitimate and often used practice, however.


There is usually a maximum allowable reservoir capacitance stated in
rectifier tube data sheets, exceeding this value can strip the cathode as
heavy charging current is drawn before a full space-charge has developed at
switch on from cold.