Interconnect cable sut to valve pre

[new2Krell]

A recent switch around in my audio system requires a shorter interconnect between sut and valve pre. For the first time I have been drawn into the discussion about cable capacitance as a result of the search for a shorter cable. In the past, I have just used whatever interconnect was best from the std phono cables I already owned. This turned out to be an Atlas Hyper Symmetrical as this was the only cable that did not induce hum. The Atlas Asymmetrical that I also had, generated hum. Clearly these cables are not all created equal.

Because of the move around, I can now get away with a 0.5m cable instead of 1m. This will reduce cable capacitance automatically on a like for like basis, but how much does this value really matter? Is it maybe a case of, beyond a certain limit it becomes irrelevant?

I have a Koetsu Black feeding an Ortofon Verto, in turn feeding into the mm input on a valve pre-amp. I don't particularly wish to spend a fortune on a new cable, but it does still need to be capable. One that I have come across is the Rothwell River (UK). The company also manufactures sut's, so I presume this cable is a pretty decent match for these devices. Regarding capacitance, the figure for the Atlas Symmetrical is 100.99pf/m, ca. 31pf/ft, the River 64pf/m, ca, 20pf/ft. Changing from the Atlas 1m to River 0.5m, actual cable capacitance will drop from 101pf to 32pf, is it possible to say what effect this will have, if indeed any, or it even matters?

For the record, another cable I may consider is Blue Jeans LC1, This would be slightly cheaper and has a lower capacitance (12.2pf/ft). Any comments on the subject, and these cables, would be appreciated. I am also open to any suggestions for other cables that anyone is happy to recommend. Many thanks!

 

[theflattire]

Capacitance is not really important with MC carts.

 

[Alrainbow]

Due to a low imp of moving coil carts cable capacitance is not important.
Now phono pre to pre amps its more important.
Blue jeans are good but the low cap cables are very stiff.

 

[new2Krell]

Appreciate the initial comments. I have been trying to inform myself on this subject since my post. Capacitance is something I never considered previously. It seems both comments are correct, but it does seem I should really choose a low capacitance cable from the sut to pre. Whatever "low" may be is most certainly open to debate I guess, but my thought is, provided I go for something lower than the present Atlas I shouldn't go far wrong. Provided, of course, the cable also has good shielding. Both cables I mentioned initially fit this criteria, but from the last comment, the flexibility of LC1 sounds like it may be a concern. The Atlas is also quite a stiff cable, another issue in addition to it being too long. The cable I choose will need to bend over an aproximate 15cm radius, if anyone can confirm the LC1 would be ok to do this without stressing connections it would be appreciated.

 

[Alrainbow]

Using a sut is perhaps difficult to make right. But it also has no noise in its voltage gain that’s needed
don’t get attracted to mega bucks cables
Not at a start Mogami , blue jeans and a few others use real spec wire buy
Real makers.
Belden is one maker
some expensive cables are also good but it’s better to start with cheaper ones
the sut is also a challenge perhaps bigger then the cable choices

 

[theflattire]

I use DH Labs Pro Studio, low capacitance, silver plated copper, shielded and flexible.

 

[new2Krell]

I use DH Labs Pro Studio, low capacitance, silver plated copper, shielded and flexible.

Hmmmm, that one sounds good, but perhaps a little pricey. Having said that, a short cable is maybe not the earth.

 

[new2Krell]

Using a sut is perhaps difficult to make right. But it also has no noise in its voltage gain that’s needed
don’t get attracted to mega bucks cables
Not at a start Mogami , blue jeans and a few others use real spec wire buy
Real makers.
Belden is one maker
some expensive cables are also good but it’s better to start with cheaper ones
the sut is also a challenge perhaps bigger then the cable choices

Now considering three cables, just added Mogami 2965 to my shortlist. I can see me ordering a couple of different ones to try. I could make use of the preferred one (if there is any difference) for the sut - preamp, the second for cd - preamp as that cable is also a litte on the long side now, but less important, I feel.

 

[new2Krell]

I use DH Labs Pro Studio, low capacitance, silver plated copper, shielded and flexible.

Actually, the Rothwell River sounds rather similar, also silver plated copper and flexible.

 

[new2Krell]

0.5m Mogami 2965 ordered earlier today, but...... I have a "niggle" in the back of my mind. It stems from the experience with the various cables I already owned, and tried, between the sut and pre when I first connected the sut. Only one cable I had produced no hum in this position, the Atlas Hyper Symmetrical. A bit of research suggests this is a kind of balanced cable? I also own, and tried, the Atlas Hyper Asymmetrical version, basically a coaxial cable, in the same position which produced a level of hum. I am now wondering whether hum will be audible with this Mogami cable, as this too is described as coaxial. I should know the answer in a few days.
Has anyone had hum issues with cables (any cables not necessarily Mogami) between a sut and preamp? What did you find the cause to be?

 

[christensenleif@msn.com]

whatever cable you choose
to obtain humfree connection from arm to riaa via SUT:
hook up tonearm gnd wire to riaa chassis gnd
hook up SUT gnd to same riaa gnd
do NOT connect arm gnd to SUT, but directly to riaa

 

[new2Krell]

whatever cable you choose
to obtain humfree connection from arm to riaa via SUT:
hook up tonearm gnd wire to riaa chassis gnd
hook up SUT gnd to same riaa gnd
do NOT connect arm gnd to SUT, but directly to riaa

I am curious what the situation will be with this Mogami cable. Hopefully hum will not be an issue, but if it is I thankfully have something to try.
Thanks for the tip!

 

[christensenleif@msn.com]

My point is that it’s the gnd scheme that is the problem, not the cable

 

[theflattire]

Hmmmm, that one sounds good, but perhaps a little pricey. Having said that, a short cable is maybe not the earth.

I bought the cable in bulk and terminated myself with AECO silver RCA.
Total cost for a three foot run was about $100 though I have it hard wired on the phono side.
DH Labs often runs specials.

 

[new2Krell]

My point is that it’s the gnd scheme that is the problem, not the cable

I appreciate your comment. The thing is, I have a cable that works (no hum) with the connections as they stand. This was the only cable from my collection that did so. The fact that this one does not produce any hum suggests there is also something else in play (with this particular cable). I hope the Mogami behaves in the same manner and doesn't generate hum when it arrives but, based on my previous experience, I am rather sceptical as all other cables I previously tried generated a level of hum. The good news is, you have given a possible solution should it be the case. I will simply swap the RCA cable first and see what happens, then set up the earth as per your instructions if there is hum.

 

[new2Krell]

I bought the cable in bulk and terminated myself with AECO silver RCA.
Total cost for a three foot run was about $100 though I have it hard wired on the phono side.
DH Labs often runs specials.

That sounds like the way to go! I will see what my experience is with this Mogami. Going forward, I could maybe go down the diy route too. Thanks!