SME3009 S2 Improved - detachable headshell, capacitance question

[Teleton]

Hi everyone,

I have the original SME cable, one end is the 4 pin attached to the arm can. The other end are SME dull grey RCA’s.

I am trying to find the capacitance, of this tonearm lead to compare with my various cartridge manufacturers cable capacitance recommendations.

My phono stage (schitt mani) input capacitance is 100pf. So e.g. the Shure SC35C recommendation says Optimum Load is 450 pf/channel for cable and amplifier input (do they mean phono stage amplifier ?)

Presumably therefore a tonearm cable of equal to or less than 350 pf in this example would be correct.

What is the sound effect of more or less capacitance than the optimum?



Cheers, Steve

[Barry]

I measured the cable capacitance to be 125pF for the standard 4' cable. To this you need to add ~20pF for the wiring in the arm
tube.

https://theartofsound.net/forum/showthread.php?24838-SME-3009-Series--(iIImproved)-fixed-headshell

So say 150pF in total, which with the 100pF of the phono stage, means you need to add an additional 200pF (either 180pF or 220pF should be fine).

[Teleton]

Thanks a lot Barry.

[Teleton]

Barry,

The sound is excellent already. What would typically, be the effect on the sound if I add more capacitance?

Also how would one be able to add more capacitance, without soldering components?

[Barry]

Barry,

The sound is excellent already. What would typically, be the effect on the sound if I add more capacitance?

Also how would one be able to add more capacitance, without soldering components?

Hello Steve,

Too much capacitance will dampen and curtail the treble end, too little can exaggerate the top end. I would ask Marco for his thoughts on the optimum capacitance loading, as he has recently looked into it with his own Shure SC35C.

I believe Marco purchased a set of Y-adapter leads and a set of loading plugs for that very purpose.

[Teleton]

Hi Barry,

I have learnt something there, it makes sense when you know these things, instead of guessing, so thank you.

[Barry]

Here is the post by Marco which refers to the Y-adapters and the capacitance loading plugs:https://theartofsound.net/forum/showthread.php?70424-The-Marco-boy-main-system-as-of-August-2020/page4 (post 35), and https://theartofsound.net/forum/showthread.php?70424-The-Marco-boy-main-system-as-of-August-2020/page21 (post 205).

He chose the 150pF loading plugs. (See also his post 206).

[Marco]

Yes, and for the sake of completeness, I finally moved to the slightly higher capacitance 'Red' plugs, which are rated at 250pF, after having reduced the overall capacitance present by swapping the wired Y-adaptors for brass splitters, shown on the thread concerned - these:

https://www.ebay.co.uk/itm/Gold-Plated-RCA-Phono-Splitter-1-Plug-2-Sockets-Audio-Y-Adaptor-PAIR-PHOSPL01/151103810623?ssPageName=STRK%3AMEBIDX%3AIT&_trksid=p2057872.m2749.l2649

...which further improved the sound, but necessitated the need for the use of the higher capacitance 'Red' plugs, as mentioned. That combination was the best sounding and the one I eventually settled on. However, I should stress that this stuff is very much system-dependent and not in any way definitive, so as ever use your ears and suck it and see!:cool:

Marco.