Ian Jackson wrote:
In message , "Dave Plowman (News)"
writes
In article ,
Ian Bell wrote:
I need to send an audio signal from a 50K ohm source over a distance of
a couple of feet in a screened cable. However, most audio coax seems to
be about 100pF/ft so 2ft of this and 50K will turn over just below
16KHz. So, anyone know a source of low capacitance audio coax?

Those sort of output impedances were common in valve days. Use a video or
RF coax to your requirements. Maplin sell a range by the metre.

75 ohm RF coax is typically 50pf/m.
Of course, you could use car radio coax (even if the inner is a
distinctly flimsy). That is even lower (say 35pF/m).
Try a Google on car+radio+coax+low+capacitance. This is one of the more
useful hits:
http://209.85.229.132/search?q=cache...fe.com/phpbb2/
viewtopic.php%3Ff%3D3%26t%3D4791+car+radio+coax+lo w+capacitance&cd=1&hl=e
n&ct=clnk&gl=uk


Yes, so far URM70 at 67pF/metre seems the cheapest alternative, but
RG62A is better at 48pF/metre and both are readily available (Maplin and
Farnel) and RG114 at 6.5pF/metre seems best if I could find a UK source.

Cheers

Ian