You are here

Log in or register to post comments
hcsunshine
hcsunshine's picture
Offline
Last seen: 2 days 23 hours ago
Joined: Nov 13 2011 - 4:06pm
hey commsysman...TT to phono stage cable question

i notice you advising folks to keep their cables between their turntable and phono stage short (under two feet). I also notice that the cables coming out of my music hall MMF-2.2 are a fixed length (about 3 feet) and do not appear removable. so I guess it's not possible for me to keep my cables under two feet?

commsysman
commsysman's picture
Offline
Last seen: 2 days 6 hours ago
Joined: Apr 4 2006 - 11:33am
Cables

The main issue there is the capacitance of the cables, which loads the cartridge and could affect its frequency response.

Since Music Hall installed those cables, I would assume that they used a special type of cable that has a low per-foot capacitance, to insure that the total capacitance is OK. You should be fine going with what they supplied.

When a person just connects any old cable to the jacks on the back of a turntable, the cable capacitance can vary considerably, which is why I recommend keeping them as short as possible.

You can actually look at the detailed specs on your cartridge, which will tell you the maximum recommended load capacitance. You need a capacitance meter to actually test the cable capacitance(with the cartridge temporarily disconnected/removed).

Just for an example, the Ortophon 2M Blue cartridge recommends a load capacitance of 150 to 300 picofarads, which is probably about what you would get with two or 3 feet of various cables.

The scenario where people get themselves into a problem is when they put 6 or 8 feet of cable onto the turntable. That will almost always result in excessive capacitive loading and have an adverse effect on the high-frequency response of the cartridge. This is more likely when they have the phono stage built into a receiver or amplifier and run a longer cable the whole way. That can be a problem.

hcsunshine
hcsunshine's picture
Offline
Last seen: 2 days 23 hours ago
Joined: Nov 13 2011 - 4:06pm
AOK...

good to know i'm good to go in that regard. thanks. enjoy the tunes.

commsysman
commsysman's picture
Offline
Last seen: 2 days 6 hours ago
Joined: Apr 4 2006 - 11:33am
Cable capacitance.

Just for the hell of it, I decided to see what capacitance some of my interconnect cables have.

I tested one Monoprice Premiun RCA cable, #2864, 6 feet long, and one was a whopping 750 picofarads for 6 feet, which is very very high.

I also tested a Straight Wire cable, around 5 feet long, and it tested a total of 125 pfd for 5 feet. one heck of a difference.

I suspect the Straight Wire cable uses a larger center conductor and a different shield configuration.

In any case the Monoprice cable, with all of that capacitance, would be a bad cable to connect to a turntable. Its capacitance is very high, at over 100 pfd per foot. Odd.

Demondog
Demondog's picture
Offline
Last seen: 3 days 7 hours ago
Joined: Feb 22 2009 - 5:01pm
Just a story.

The primary motivation for re-wiring my 1983 vintage Japanese turntable, was to have a low capacitance cable. The original thin hardwired cable was of unknown specification, so I felt like I was shooting blind as far as setting capacitance loading options on my phono-preamp. Using a known low capacitance cable gave a little more certainty to choosing a reasonable loading, plus the useable range of capacitance loadings was increased.

Ended up using LC-1 interconnect cable from Blue Jeans Cable (What else? haha) at 12.2 pF/ft. I used just over two feet so you can do the math. Then added 200 pF at the phono-pre. I'm pretty confident that I'm in the Ortofon cart's recommended range now, where as before, I had no idea

wkhanna
wkhanna's picture
Offline
Last seen: 4 days 3 hours ago
Joined: Jul 13 2007 - 1:46pm
As stories go.....

...This a good one with a happy ending.

Valuable information.
& I agree with with your general assessment of BlueJeans Cable.

Bill - on the Hill
Practicing Curmudgeon & Audio Snob
- just an “ON” switch, Please -

  • X
    Enter your Stereophile.com username.
    Enter the password that accompanies your username.
    Loading