"Derek Geldard" wrote in message
...
On Tue, 20 Nov 2007 12:42:49 GMT, "Arfa Daily"
wrote:



Anyone reckon I can rob the crystal from a piezo ceramic pickup to fudge
a
functional and "as original" repair?
I assume piezo-ceramic is not prone to this problem over 40 years.


As I recall, ceramic cartridges do not have anything like as much output
as
a genuine crystal type. Why not just replace the whole cartridge with an
SX5H or whatever ? I seem to think that Dansettes were fitted with a
comparitively 'modern' type such as this, anyway.


ISTR that cheap record players that just had a single valve output
stage and no pre-amplifier used a "High-output" cartridge. (Is that
what the H in SX5H means ?) a standard output cartridge would be very
quiet and a ceramic quieter still.

Also FWIR that output valve would typically be a UL84 or similar (not
as a rule EL84), with 100ma (80v) heaters fed off a tap on the shaded
pole turntable motor, to save the cost of a filament transformer.

The crystal cartridges didn't need any excitation voltage.

DG


Yes Derek, that's it exactly. I did one just last week that used a UL84 and
UY85 reccy, fed just as you say, by a tap on the motor winding. I seem to
recall that those crystal cartridges had an output approaching 2v p-p, and
obviously, with a very high impedance in the order of megs, which matched
nicely for level and Z, directly to the grid circuit of the UL84. Ceramic
cartridges, on the other hand, only have an output of 200 mV or so I think,
at an impedance of around 50 - 100k. I think that you are right that the "H"
is for high. The BSR SC5H is a high output ceramic, so I guess it's "S" for
stereo, "X" for xtal, "C" for ceramic, and "H" for high.

It's all going back a bit to my apprentice years now, but I have a dim
recollection of later units that were fitted with a ceramic cartridge, using
something like a UCL84 which contained a triode as well as the output
pentode, and that the triode was pressed into service as a preamp.

Arfa