Dear Paul,
As I said before, yes there are two filter blocks in the IF of the Mark
VIB. One is a four pole and the other is a six pole. The reason for
having one in close proximity to the front end is obvious. Actually, in
all truthfullness, the Front end is probably the weakest element in the
tuner. It was a fully enclosed assembly from a European manufacturer and
was selected BEFORE I arrived at SAE. Its performance is OK however, I
would have much prefered to use an ALPS front end. That's water over the
dam.
I've tried till I'm blue in the face to tell people that once an
electrolytic has formed, it looks like a batery yet without the battery
wear-down. Barring any faults that would be machanical and/or
manufacturing, an electrolytic should last for decades. As long as it
isn't stressed with overvoltage and/or wild temperature deviations,
there really are no wear out mechanisms per se. It pays to be very
conservative with the original specs. As far as the scope tube is
concerned, it was a very common tube back in those days because unlike
the tube used in the Marantz 10B which was round, this one was
rectangular. If you find a source, let me know.
James Bongiorno
