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How important is the cable between the SUT and phono pre?

I know when using a cable between a MM cartridge and the phono pre it's very important to take into account the capacitance of the cable for cartridge loading.

I don't recall seeing a discussion on the importance of using low capacitance cables between a SUT and  phono pre.  

I picked up a Denon Au-340 to replace my Denon AU-320 in my system and the AU-320 has built in cables that run to the phono pre, hence my question.

Is there a way to figure out the capacitance requirement for this cable or is it not that important? Will a good shielded cable work fine?

I don't want suggestions on some high dollar cables, that will never happen. I have about 15 or 20 pairs of cables that I picked up over the years, I can always go through the pile and measure the capacitance if necessary.

Thanks

 

BillWojo

billwojo

Showing 2 responses by intactaudio

intactaudio
293 posts
 

However, transformers do not reflect secondary load C to the primary.   

They absolutely do reflect any capacitance seen on the secondary by the turns ratio squared.  Say you have 150pf (50p cable + 100p input)  at the secondary of a 1:20 SUT.  This will appear as 150*20*20 or 60,000pF or 60nF or 0.06µF to the source.

 

dave

intactaudio
293 posts
 

Would love to see a cite with a detailed technical explanation.

You are looking too deep into it.  This is the simplest basic transformer theory and the simple ideal transformer model is all that is required.  The problem you are having is assuming the load is a resistance but in reality it is an impedance which can be any combination of R, L or C.  By the time you get into the models that include external capacitive loads, the concern is more about how that capacitance interacts with the internal R,L and C of the transformer and not how it reflect back to the source.

dave

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