Cap types and values for splitter cable

[Chris]

I am in the throes of testing various values in my Y splitter cables to find the capacitance value that sounds best with my MM cartridge in my set up. I made the cables up using tiny ceramic caps inside three sets of load plugs (80, 180 and 390 pF respectively) but I had no real idea of the interval between values to go on - my cartridge manufacturer reckons a total cap value of 400pF but that includes arm cable, phono input and the splitter so we’ll see. As expected I think I have discounted the 390 ones and this week I am trying the 180 which sound much more like it. Anyway I am writing to see if ceramics are a good choice or if, when I go for the definitive caps to fit inside my phono stage, should I opt for other types.
By the way, Is my EE mate way out of order when he says I can forget the capacitance of arm cable and splitter cable because values are given per kilometre length and a few centimetres are not going to make any difference.
P.s. In my system, there is definitely an easily notable to the ear difference between differing cap values, at least between 180 and 390 pF. Like the difference between crap and good.

 

[Mike P]

I went through the same process myself.

In my case the recommended capacitance for my cartridge is about 400pF and I measured the total capacitance of my arm plus cable was about half that, so I needed to add about 200pF. There is no internal loading capacitor in my phono stage.

I made up a selection of values but settled on 220pF.

You're not going to hear the difference between +/- a few pF. My selection was something like 47pF, 100pF, 180pF and 220pF. I just used what I had in my parts box.

When you make your final selection, COG/NPO would be a sensible choice.

It was well worth the effort and made an appreciable improvement.

 

[Chris]

Many thanks for reassuring words, Mike.
I must say with the 390pF plugs fitted, Bill Evans´piano sounded like a Chad Valley one
Cheers,
Chris

 

[Arkless Electronics]

Arm cable will usually add around 60 - 180pF depending on cable type etc.

Ceramic fine so long as C0G/NP0, as Mike said.

 

[Chris]

Thanks Jez, and what approximate value should I give to the splittercables (approx 10 inches long) with cheapo RCS plugs ?

 

[Arkless Electronics]

40pF ish I guess... If you want to be right then you'll need an LCR meter/bridge and actually measure it. Obviously there is the value of the fitted loading capacitor in the phono stage to take into account as well.

 

[Chris]

Thanks

 

[Chris]

liking how it sounds with 80pF in the load plugs. I think the load cap on my phono input is a 51pF tantalum. When and if I decide to solder in a new load input cap inside my phono to take this new value into account, should I go for an approx 130 Tantalum or stay with a 130 ceramic. or mix the 2 different types of 50 and the 80pF caps ?

 

[Arkless Electronics]

liking how it sounds with 80pF in the load plugs. I think the load cap on my phono input is a 51pF tantalum. When and if I decide to solder in a new load input cap inside my phono to take this new value into account, should I go for an approx 130 Tantalum or stay with a 130 ceramic. or mix the 2 different types of 50 and the 80pF caps ?

It's not tantalum!! Probably an epoxy case ceramic. Adding a bit for the Y lead then 150pF is a standard value.

 

[cobbers]

Recently made up a switch plate to go inside a Hafler DH-110 - the capacitor sockets on the inside of the input board are not easy to get to - the fundamental value on the phono stage is stated to be 30pf so added optional caps of 33/82/120/160pf - fine tuning up to 300pf with the arm cable.