Do 5-pole DIN tonearm connectors deteriorate the sound?

Currently I have issues with hiss and a deep background hum, indicating bad shielding of the tonearm wires and some grounding issues.

@reimarc You need to figure this out before worrying about rewiring the arm or dealing with connectors! Otherwise you may find you have the same problem after all that work! Based on other comments in your opening post, I suspect this will be the case.

FWIW, the ground wire does not have to be carried within the shield. It might help to explain how tonearm wiring actually works:

The cartridge is a balanced source. Like any balanced source, the signal is carried in a twisted pair of wires to the input of the preamp. It does not reference ground, hence the ground wire is merely to connect the shield (the arm tube) to the preamp chassis ground. On this account, the actual shield can be around the signal wires only.

However, you have a foil shield which is great at RF frequencies but bad bad not good really terrible for audio frequencies. Its no surprise you're having hum problems. The 'shield' is picking up noise and injecting it into your audio wiring within. So you'll want to rethink your tonearm cable, not your tonearm wiring!

Since you are likely running the system single-ended as most people do, its acceptable to shield the '+' (plus) output of the cartridge with the '-' (minus) output once the arm wires have exited the tonearm, but this should not be the same as the ground wire connection. That's about the best way to connect a balanced source to a single-ended input and is why tonearms are the only 'single-ended' source that needs the ground wire- in fact its not a single-ended source.

Any connection will deteriorate sound just like 5-din, but why you're asking specifically for 5-din, not sure

Because 5pin DIN is the standard connector for most tonearms. Since I like to collect tonearms I like the 5 pin DIN connectors. If everything is in good condition than there shouldn't be any degridation or signal loss. But I'm sure others with golden ears will argue this point.

BillWojo

I have Tonearms that have the DIN Connection and a Tonearm that has a Direct Wire routing, which is from Tags to RCA Phono.

I have formed the view that the less connections is for the better, but have not to date, got comparisons  put in place to discover where the discernable differences are to be found.

Where I have recently discovered discernable differences for the better, is relating to the Wand Wire used. The demonstration has included a Wire Type not commonly seen in use as a Tonearm Signal Wire, and also has the Wire being used as the Tag Wire. This experience has been quite revelatory, it has left myself wanting to incorporate the same into a Tonearm I own of the same design.

If I could attach the Wand Wire to the Cart's Coils and Directly Terminated to the circuit at the Phono Amp' end, that would be for me the very best outcome, but as it is quite a fragile design and will be impractical, the direct wire method will be the option used.  

@reimarc If I am interpreting your inquiry correctly. It looks like you are trying to learn about controlling hum in the system.

When using the methods I am familiar with I have not had a Hum issue due to these Wiring Configurations, neither have I been aware of Hum in others systems that use either of the options.

If you can make time available to try out a selection of wire types, you might discover a signal wire that offers a SQ way above what you thought was available.   

@lewm . Isn't your BMC balanced?  I can not separate having a current mode phono stage from running balanced as they happened together. There is no question to my ears that the combination of the two is distinctly better especially when it comes to bass and that is most definitely not psychological. 

Some Reed arms have removable arm wands adding an additional connection. They offer the wands in different EFs which is good for cartridge matching but I refer the Schroder approach of supplying different cartridge mounting plates.

Having experienced problems with various tonearm connections in the past I avoid them religiously. Theoretically the lower the cartridge output the worse they are so I think you are wise to use straight wired arms with your low output cartridges. I think you can also order Kuzma arms straight wired. I am not totally sure.