Need help with DIN to RCA phono cable troubleshooting

Bass frequencies missing in action would suggest one channel may be out of phase.
5th wire on DIN connector should earth the arm and be connected to chassis earth on phono or pre.
If the 2 signal channel cables have a floating shield ( as in twisted pair plus shield ) most phono cables connect the floating shield to the -ve side of the RCA ( if not using balanced connectors ). Personally I prefer to solder wires to the floating shield and keep them separate from the RCA. This means that you can connect the floating shield to the chassis.
The problem with connecting the shield to the RCA is that it is dumping noise into your phono section directly.

When testing for continuity make sure you disconnect the cartridge. In some instances a meter can burn out coils in a MC cartridge.    

nandric
Dear Dover, Which method should be used to connect the XLR
connectors? Should the ground wire from pin 5 in the Din5 connector
be split in two such that each can be soldered to the pin 1 on the
XLR connectors? Or should only the (floating) shield of both
channels be connected to the pin 1 on the XLR connectors?

Nandric - for all phono both balanced and unbalanced the arm earth ( 5th pin ) should be a separate wire which you connect to preamp chassis. This simply grounds the arm itself and has nothing to do with the cartridge signal.

Floating shields on the signal cables should only be connected to earth at one end.
In the RCA's at the preamp end I connect the floating shield ( assuming a twisted pair plus shield construction ) to the chassis by cutting the connection to the RCA and soldering a tail for connection to the preamp chassis. This reduces the opportunity for noise collected by the shield to enter the phono signal in a single ended system.
In this arrangement you end up with 3 earth leads to connect to the preamp chassis - tonearm earth/ground plus left and right channel floating shield earth/ground.

XLR's have a separate -ve signal and earth/ground in a balanced system. Therefore you only need to ensure the shield is connected to the earth/ground pin which is already separated from the -ve signal. The tonearm end is left floating ( not connected ).   

Atmasphere-

I dont agree with your comment that my solution above is incorrect.
Maybe you misunderstood what I wrote.

The tone arm is in fact the ground (which is the ground wire in a single-ended system). So the arm wand provides a grounded shield to the cartridge wires within.

Agree

This continues through the DIN connection and splits to the shields of the left and right channels.

I don’t think this is optimal in a signal ended system. The fifth pin grounds the arm. You run the risk that if someone connects the shield to the RCA at the preamp end then an earth loop is created.

My suggested solution outlined above is to separate the floating shields covering the signal cables and earth the floating shields on the signal cables separately at the preamp end ( assuming twisted pair plus shield signal cable construct ) to the preamp grounding post.

What I actually said was that in a cable that has a conventional twisted pair plus shield construct that I prefer to disconnect the floating shield from the RCA and connect the floating shield ( not the -ve signal from the cartridge ) to the preamp grounding post/chassis via drain wires.

If I read your post correctly you are grounding the floating signal shields at the sending end ( tonearm ) via the arm ground wire to the preamp chassis, whereas I ground the floating signal shields at the preamp end separately to the preamp grounding post. Since all three shields are floating and only connected at one end they cannot create an earth loop.

In my experience my arrangement has demonstrably lowered the noise floor.

In a single-ended system it is advantageous to prevent the ground side of the RCA connection from being shorted to the phono preamp chassis (otherwise it is possible to introduce ground loops). So the only ground to be seen at the chassis should be the ground wire of the arm itself and not the minus outputs of the cartridge!

In my post above I never suggested connecting the ground side of the RCA connection to the preamp chassis.

Again, what I actually said was that in a cable that has a conventional twisted pair plus shield construct that I prefer to disconnect the floating shield from the RCA and connect the floating shield ( not the -ve signal from the cartridge ) to the preamp chassis via drain wires. In my experience that arrangement has lowered the noise floor.

In summary the only difference between you and me is that in a single ended system you ground the floating signal shields to the DIN whereas I ground the floating signal shields at the preamp ( ground post ) end by separating the floating shield from the RCA and running drain wires ( leaving the DIN end floating.