PhonoStage interconnects

Gaffer74

Gaffer74

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Hello.

Reading the instructions with my gram amp 2, the company seems to recommend using "CT100 standard co-axial cable" for the interconnects.

Well in maplins, their equivalent is FT100 (code XS17T).

I'm planning on making my own IC's using the Shark phono plugs (AQ57M) and thought about Naim's advice re: siting their phonostage inside LP12's to minimize delicate signal path between the arm and the stage. So I plan on making a 30cm IC going from deck->gramAmp, (i can sit the stage behind the deck/ or suspend below the shelf) and then a 70cm IC to reach the PrimaLuna.

1) Firstly, is the FT100 co-ax cable good enough or could I get a better one for not much more? (ft100=99p/m)

2) Will it really matter between 30cm I plan to make, or will a 100cm (giving me more leeway re:siting) be just as good?



Cheers for any help


PS alternatives to the FT100 would be:

2: http://www.maplin.co.uk/Module.aspx?ModuleNo=125&doy=27m11D

or

3: http://www.maplin.co.uk/module.aspx?ModuleNo=9512&doy=27m11

or

4: http://www.maplin.co.uk/module.aspx?ModuleNo=131&doy=27m11

I haven't made IC's before and am not sure what would fit the bill, but the last option (4) looks good too
 
You need to minimize nasties with arm to phono. Stuff like the Van Dam screened mic cable maplin do is good, nice low capacitance, nice thick screen etc.
Yes, keeping the arm-phono connection short is a good idea, the phono output will be able to drive the line far better than the tiny output from the cart.
 
Z is having a argument with a couple of his amps at the mo, but Im sure he'll reply to a PM.

What are the reason for that them suggesting that cable??

If I was going to use a coax such as that, Id strip out the centre core and use something like 0.6mm 4n Silver. If you get a coax with an insulator made up of 'cells' Id use 2 lenghts of Silver, one for the signal and the other for the return. You could then solder one end od the copper braid to the phono and leave the other free, semi-balanced stylee.

Id keep it as short as possible.
 
Argument over only one amp at the moment !
Just bought some new groove tubes for the working one, but not fitted them yet.

I've tried every cable that maplin do...the best is the silver shark priced at about £16/0.25m its performance and price compare unfavourably with my type 1.

If you want to contact me ..feel free but I'm not around till monday
 
i have spoken to graham at length about this very issue. he recommends the ct 100, because it's only 50ohm cable and it's well shielded. apparently it's primary design use, was for powered satellite dishes, which carried both the signal and the power for the satellite motors. apparently it has a lot of copper in it to facilitate this. i just made up a pair to link my exp to my 2se. haven't got the new cartridge yet, so i can't really comment on the sound. there is some hum though, so tonight i'm going to replace my unshielded ic from the 2se to my pre with another 6inch length of ct100 cables. apparently there can be an issue with mc phono stages and tube amps if you don't shield adequately... we will see.
 
Yep there very sesitive to small signals coz thats what there dealing with. Not entirely certain I'd want to leave my precious audio signal with sat dish down lead though, you are using two runs ? If you use a single run your running the sig through the foil shield in effect. If you can move the head amp away from the valve and other transformers....probable source of hum. If the pics accurate.
 
But presuming the I/C's are fitted with phono plugs there will be very little impedance??? is it recommended that an impedance of 50ohms is advantagous?? or am better going back under stairs and talking to the spider??
 
the head amp is stacked under the 2se, behind the pre on the right hand side of the rack. (only place i really had room...) between the 2x psu-1s and the the transformers in the pre, power and the cd player, it's very hard to find anywhere that isn't near a transformer of some variety.

graham seemed to think that the hum could be coming from either the cables picking up rfi or the seaker cables also acting as antenna... i have to admit it gets a bit beyond me, but he seemed to think that the hum was probably coming into the exp and the 2se from the outputs. hence my next attempt at screening the output of the 2se.

graham also felt that the shear quantity of copper in the ct100, would over the short distances we are talking about, make it as good as anything. i am, after i have everything up and running hum free, willing to try other things to see if this is really true.

as far as the impedance thing goes, isn't that very low anyway?
 
Thanx for all the info guys.

I ended up using the Shark audiograde cable along with Shark phono plugs...about £15 all in. Enough for two IC's and they have an extra Earth drain wire, which I will use to connect between phonostage and TT earth points.
The TT hasn't arrived yet, so I hooked it up to Radio 4 via and 3 via my DVd reciever.....wonderfull transparent sound :) , I'm well pleased.

p10001912ck.jpg


Can't wait for the TT to take an inaugral spin.

Thanx Again
 

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