Phono cable (RCA-RCA) from TT to Phono Pre Question


Hi all,

Something that came up in a conversation with a friend was that the cables I am using for my TT to phono-pre might not be ideal at all. I'm currently using custom RCAs made with Canare Lv-77s (capacitance 67 pf/m; double-shielded) with a ground wire. What I was told was that it really needs to be a low capacitance wire to get the best results (sub 50 pf/m).

I admit, my technical knowledge when it comes to matching cables like this has a lot of gaps, so this may be a silly post, but I wanted to investigate further.

Anyway, when looking around at various options online, very few cable manufacturers list the capacitance ratings at all - like Cardas, Shunyata, and others I looked at quickly just going off the top of my head. I did find ratings for Mogami and other Canare cables, but didn't see anything that could really be categorized as 'low capacitance.' - though maybe I missed them.

I don't really want to spend a ton of money on one right now, and it's just RCA-RCA. I have separate ground wires so I can use them with RCAs when needed. So if this is an actual problem I should be concerned about then can anyone point me to some solid (affordable) low-capacitance options?

Actually, I suppose I should simplify this to try to make it as straight forward as possible, as these cable threads tend to get contentious:

1. Is there cause for concern with the capacitance of my current cables (67 pf/m) for TT -> Phono pre use? If so, what value should I be looking for, ideally?

2. If so, what are some sub-$500 (ideally cheaper for now) options that are suitable. Not looking for reference quality at the moment as it'd be a band-aid 'fix' if this is indeed a problem until I can do some demoing of better stuff later (though suggestions for demo later are fine too - but don't need to go into detail about their sound or anything since that is going to be totally dependent on how they end up fitting in my system).

Thanks for any guidance! Happy to look at any reference material anyone can send along on this topic as well. Always appreciative of learning opportunities.

128x128mmcgill829

Capacitance is really a concern only with MM cartridges. What cartridge are you using?

@mmcgill829 - rarther than simply replace the cables with another basic interconnect, I would take a look at Zavfino cables. They have a lot of experience with well designed phono cables.

Cable science gets complicated and the capacitance of a cable is just one facet of good cable design.

My own interconnects, that I have been told work very well as interconencts from TT to Phono stage, have metrics per meter of

  • Capacitance = 38 pF
  • Inductance = 1.3 uH

Some might be of the opinion that the inductance number is on the high side, but it seems to make little to no difference to my ears

Personally, I went with a one piece harness from the cartridge to the phono stage to eliminate as many juction points as possible. The results were very impressive

Hope that helps - Steve

@cleeds Ah, okay. Great! Good to know. I use a MC cartridge (Hana ML), so I suppose this isn't a concern for me then!

@williewonka Thanks for the info. I don't see these metrics listed on their website for their offerings (do they have them listed elsewhere than the product pages?), and they only offer phono cables with DIN vs RCA-RCA. I'm not interested in rewiring my table, so I'm not sure these will work for me.

@mmcgill829 - while zavfino does not post values, several reviews state that all their cables are described as low capacitance in several reviewse. I would think they would b lower than 38 pf per meter, probably closer to Nordost cables.

 

Hope that helps, Steve

WyWire Cables list the capacitance of their cables. Typically, 7.9 pF (per foot at a frequency of 10kHz).

Not too many years past I was invited to a Bake Off between RCA>RCA Phono Cables. The Cables were priced between low  £100's and £500ish, it is not easy to recollect everything.

There were 3 X Zafino Cables from differing prices, I recall one being Silver..

I also recall another Brands Silver Cable was unbearable, in relation to produced Sonic.

I supplied my own Silver Wire Cable to the line up as well. 

The Set Up was SME 20/12 >Cart'? > Graff OTL Valve Amp > Quad ESL

The System Owner selected a Copper Wire Cable at apprx' £160

I preferred a Different Copper Wire Cable to the one selected. 

It is difficult to recommend a Cable, there are differences that are detectable. 

Buying at a price that enables a turnover of Wire Types and Cable assemblies will supply a better understanding of how the Interface impacts on a System. 

For The Record, today I use PC Triple C Wire Cable in place of my Silver Cable of old, at present, it is difficult to imagine how this Wire Type can be bettered within my own system. 

 

@mmcgill829 If you have a MM high output cartridge, the inductance of the cartridge and the capacitance of the cable set up an electrical resonance that might be ultrasonic or might be at the high end of the audio band. It might also be as much as a 20dB boost. So it can result in brightness and will enhance ticks and pops.

As a general rule of thumb the phono cable will not exceed 100pf overall. This assumes a 1 meter length meaning you want the cable capacitance to be 30pf or less per foot.

If you have a high output cartridge, this means your existing cables are making the highs bright. So this is worth fixing.

@atmasphere I suppose I left out an important piece of information in my post...

I use a Hana ML and have pretty much exclusively used LOMC cartridges for quite some time.

@mmcgill829 You still have the issue of the cable capacitance in parallel with the inductance of the cartridge, but now the inductance is much lower and higher ’Q’ (Quality, which is to say the inductor is wider in diameter than it is long). This results in a higher peaked resonance, about 30dB at a much higher frequency.

If untreated it injects Radio Frequency Interference (RFI) directly into the input of your phono section. It is for this reason you may wind up using a ’cartridge loading’ resistor, which detunes that resonance.

Again though, it is helpful to keep that resonance as high as possible, since it might help prevent the phono section from reacting to it. So changing cables might help. What is of greater importance is preventing overload of the phono section by that RFI. The loading resistor does that; but at a price- it causes the cantilever to be stiffer, which might affect how the tonearm tracks.

Some phono sections are immune to the RFI so don’t need the loading resistor.

Have you looked into the loading issue?

@atmasphere I'll admit - most of that went over my head.

I don't really have any *problems* with the sound coming out of my analog system that I can tell, and don't know what 'loading issue' you're referring to, but was mostly curious if I was being told the right thing or not about cable choice for table to phono pre-amp and if so, what I should be looking for instead.

My table uses a Cardas phono interface to allow use of RCA cables, so was just using a set of what I use for everything else in my system, but have no idea if I'm losing anything by using them vs something more specialized - or if these are inadvertently causing any issues that I don't hear because I've just used these for the longest time. In theory, if the cable isn't really ideal that's an easy fix, though finding manufacturers that post capacitance figures is...difficult at best.

So it's more of a 'am I missing an extra 5% of quality because of a dumb cable choice' question.

@mmcgill829 As far as sound quality goes, I'm sure that cable is just fine. But you might want to look into the loading issue. It can make a difference with a lot of preamps that don't like the RFI I mentioned!

Take a look at this link on cartridge loading.

In your setup I suggest you look at Auditorium23. Low capacitance, well shielded against RFI/EMI. Don’t exceed 1m length if poss.