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Interconects sheilding question

oceanobsession

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Interconnects having 2 wires and a shield , step up transformer to phono stage , is the connection of the shield made at the step up transformer or phono stage , phil.
 

Fullrange

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Personally I connect both ends of the shield.
Some call this the Japanese way.
It works for me. 🤠
 

rabski

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Whatever works best to reduce hum, basically. Every layout and system seems to differ, so in my experience the rule is that there are no rules. I have ground/lift switches on the phono stage and SUT and I run a separate grounding lead from phono stage to SUT and from phgono stage to turntable, or phono stage to SUT and then to turntable. There are endless combinations. Some simply hum badly, others are small differences. I'll probably still be swapping and changing for years.
 
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Lawrence001

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Since this has been answered, I have a slightly different question. I just bought some interconnects where the shield is the ground ie there is only 1 inner wire. (This is standard coax type I think?) They are quite bright and detailed (not necessarily in a bad way) and I was wondering if this could be the result of the cable topology rather than specific attributes of the conductors/dialectric etc?
 

Cable Monkey

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Since this has been answered, I have a slightly different question. I just bought some interconnects where the shield is the ground ie there is only 1 inner wire. (This is standard coax type I think?) They are quite bright and detailed (not necessarily in a bad way) and I was wondering if this could be the result of the cable topology rather than specific attributes of the conductors/dialectric etc?
The biggest influence on cables is the connectors. After that it is impedance and capacitance of the cables. Topology is possibly the issue as a cable with twin conductors and shield is probably 120 ohm while standard coax will be 75 or 50 ohm. I’m not sure if your cables are boutique or not but manufacturers are not above making cables out of spec in order to make them sound different.
 
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Lawrence001

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The biggest influence on cables is the connectors. After that it is impedance and capacitance of the cables. Topology is possibly the issue as a cable with twin conductors and shield is probably 120 ohm while standard coax will be 75 or 50 ohm. I’m not sure if your cables are boutique or not but manufacturers are not above making cables out of spec in order to make them sound different.
It's called Apature QF, not much about them anywhere, they look like silver coloured versions of the Mark Grant cables (which I also like).
 

Lawrence001

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Also interesting what you said about the plugs as I have a 0.5m version with different plugs and it sounds more laid back. What impact does impedance have on SQ?
 

zeta4

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Also interesting what you said about the plugs as I have a 0.5m version with different plugs and it sounds more laid back. What impact does impedance have on SQ?

If we are talking about characteristic impedance then the CI of signal cable per se will have very little if any any impact on SQ (digital connections excepted). The quoted CI of signal cables is that measured at the high frequencies at which the cable is intended to be used. For example 75 ohm coax does not become 75 ohms CI until at least 100khz. Below that frequency the CI becomes progessively much larger, how large will depend on cable properties like resistance per unit length which will vary between different makers and specifications . So different 75ohm cables can have different CI at the lower (audio) frequencies.

Whats probably more important is the individual cable properties like capacitance and shielding
rather than a specific hf characteristic impedance.
 

RobsterD

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Just built some Neotech 1220 interconnects and used a flying lead soldered to the screen which I connected to my preamp earth stud .
 

oceanobsession

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Just built some Neotech 1220 interconnects and used a flying lead soldered to the screen which I connected to my preamp earth stud .
Had a play with the 5220 and 3220 without shield thought the 5220 sounded better than the 3220
would like to try the 3220 with shield connected now on my step up , still confused which end to connect the shield , source or reciver , phil.
 

Jazid

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Connect the grounded screen of the cable to whichever end has the lowest impedance to ground.
Mr Rabski will.be along presently to explain how to measure this :giggle:😇
 

rabski

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Connect the grounded screen of the cable to whichever end has the lowest impedance to ground.
Mr Rabski will.be along presently to explain how to measure this :giggle:😇
The bit on the lowest shelf of the rack. It's 'ground' after all, so it makes sense.

Or just guess.

The latter makes as much sense as anything sometimes. Especially with low-output MC cartridges and step-up transformers. Do everything 'right' and you can still end up with hum.
 

RobsterD

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reckon the screen flying lead is the best option attached to a suitable earth I connected the receiver end
 

rabski

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reckon the screen flying lead is the best option attached to a suitable earth
That also depends. If you have some equipment with a floating ground that is referenced to case earth, then screening with case earth may cause issues. It ought not to, assuming the screen is not connected to signal ground at either end, but hum can be a real pig at times.

The concepts of 'ground' and 'earth' are tricky at best, because neither are necessarily at absolutely zero volts. More importantly, they are not at the same absolute voltage throughout a system or even within one piece of equipment.

Those of us who have messed/are messing with DHT preamps and own-build high-gain phono stages are painfully aware of this.
 
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oceanobsession

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Thanks again for all your suggestions , the hashimoto step up that the interconects are for is very quiet , but needs shielded interconnects , looking at the neotech 5220 on hifi collective it tells you how to wire them ,
RCA wiring:
RCA Plug at the amplifier end: screen + blue conductor to RCA earth. Red conductor to RCA signal.
RCA Plug at the pre-amplifier end: blue conductor - RCA earth (screen cut short, not connected). Red conductor to RCA signal.

phil.
 

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