On Thu, 26 Feb 2015 20:09:31 +0000, Sumatriptan wrote:

On 16/02/2015 14:04, Sumatriptan wrote:
Yesterday, I got a Dual 505 on Ebay for £77.

Hi all,

More from a born again vinyl user..

When the tt arrived it was packed in the original Dual packing which
would have been fine, except the transit screws were not tightened and
the counterweight was left attached to the tone arm for transit. The 505
counterweight has a plastic stem, unlike later 505-x models. Sure
enough, it was broken and the weight was rattling around in the package.

The sender agreed to compensate me for purchase of a replacement if I
could locate one. A few messages at the Vinyl Engine forum resulted in
this:

http://www.dualfred.de/

Alfred and his wife who run this shop in Munich have a large stock of
apparently new Dual and Thorens turntable parts. I saw the exact part I
needed on their website. It took a week to arrive and the brand new
boxed part is labeled 'Original Dual Zubehor'

As I don't have a fully functional preamp and the main point of this
exercise is to get some/all of my collection digitised I decided to
obtain a Behringer phono-USB UFO202 interface to quickly get up and
running.

I haven't done a proper setup yet apart from tracking weight adjustment
to try out the tt for basic operation. All seems well so far, after a
listen via Audacity...except for one issue. There is significant mains
hum which I haven't tried to fix yet.

And that's where I'm at.


Now you have to look at the earth wiring.
There are almost certainly 4 wires to the cartridge, via headshell
connectors. When they leave the arm at the bottom, 2 of the wires become
L and R signals and the others become signal grounds. Note that none of
them must be connected to the chassis in any way whatsoever! The signal
grounds are only earthed in the amplifier.

Wire colours are probably:
Blue - outside - left channel ground
white - pin - left channel signal
Red - pin - right channel signal
Green - outside - right channel ground
To clean the connectors on the headshell try the eraser on a pencil.

The chassis *should* have a connection to mains earth for safety reasons
and that's all. This is sometimes via a separate wire to a screw terminal
on the preamp or amplifier.

Have fun...