Doepfer

DIETER SAY:
The description of the customer tells me that the
system was 
manufactured in
1997 or earlier. Until end of 1997 we used a combined
power inlet/EMC
filter/fuse holder and a separate power switch instead
of the 
combination of
power inlet/fuse holder/power switch used for all
systems manufactured 
in 1998
or later. After the EMC compatibility test in the EMC
lab to obtain the 
CE sign
(EMC compatibility) it was recognized that the
expensive EMC filter is 
not
necessary. So we changed to the new mains inlet
without EMC filter end 
of 1997.
The two version can be distinguished very easily: If
there is a 
separate power
switch (not integrated to the mains inlet) it is the
old version with 
EMC filter
(manufactured until about end of 1997, maybe even
still some systems or 
frames
were sold early in 1998). If the power switch is
integrated to the 
mains
inlet/fuse holder it is the new version manufactured
1998 or later.

Obviously the EMC filter (probably the electrolyt of
one of the the 
high voltage
capacitors inside the EMC filter) has become defective
and has to be 
replaced.
It is available as a spare part from us or the
representative/dealer 
where the
customer purchased the device. It would also be
possible to use the new 
mains
inlet but in this case the complete rear panel has to
be replaced as 
the holes
for the main inlets are different for both versions.

Of course we test each power supply before we ship it
but for each 
electronic
part it may happen  that it becomes defective after 6
years (or even 
more) in
use.

BTW we think about a second type of A-100 power supply
that uses 
so-called
ring-core transformers. Roland Mayer has built a
prototype of this 
power supply
last week and we are about to do some experiments with
the new power 
supply. It
seems to be more quiet and even generates a smaller
electromagnetic 
field (e.g.
important in combination with the spring reverb).
Maybe there will be 
two types
of A-100 power supplies available in the future:
standard version and 
"high-end"
version with ring-core transformers. But as these new
transformers are 
very
expensive and have to be hard-wired and mounted by
hand to the pc board 
the
price for the "high end" power supply resp. a 6HU
frame/system will 
increase by
about 20~25 Euro. I will keep you informed as soon as
we decide to 
offer a
second type of power supply. If we do so the "high
end" power supply 
will have
the same dimensions as the old one so that each
standard power supply 
could be
replaced very easily by the new one if desired. But if
the standard 
power supply
works perfect for the user there is no need to change
to the "high end" 
type.
The modules will not sound better :-)

Dieter




=====
synthfreak(parallel worlds)
athens-greece
[Doepfer_a100] group owner-moderator

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