[SoCalWJS]

I know shorter is better, but I have virtually no choice due to space limitations. I'm looking at a run of about 20 feet.

Don't know how much the tonearm matters, but the setup is as follows: SOTA Star, ET 1.5, Grado cartridge and ModWright LS100.

[galyons]

That is likely too much resistance  and capacitance to not effect the signal.  Can you put the phono pre close to the TT and run the amplified signal to the rest of the components?

Cheers,
Geary

[Speedskater]

It's the capacitance that affects the high frequency response of the cartridge/cable combination. But if you must, Belden makes some very low capacitance co-ax cable, they call it video cable but that's OK.

[SoCalWJS]

That is likely too much resistance  and capacitance to not effect the signal.  Can you put the phono pre close to the TT and run the amplified signal to the rest of the components?

Cheers,
Geary

Wish I  could move the MW, but really not an option - too many cables running through it that would have to be lengthened, and there is no place to place it between the 2 spots that are about 20 feet apart.

Someday, I hope to have a dedicated space, but not right now.

[SoCalWJS]

It's the capacitance that affects the high frequency response of the cartridge/cable combination. But if you must, Belden makes some very low capacitance co-ax cable, they call it video cable but that's OK.

Interesting. Not sure how to terminate Coax with an RCA, but maybe I can figure it out.

How much of a high frequency roll off/loss is there? Is there a formula to calculate based upon capacitance per foot?

[neobop]

Thanks to your Grado you might get away with it relatively unscathed.  I assume this a HO Grado going into a MM phono stage?

The output of a cart has inductance which in combination with the capacitance in question effects the response.  All HO Grados have 45mH inductance, very low for a HO.  The bad news is that the capacitance of the cable is added to the that of the internal tonearm wire and again to that of the preamp input.  The sum is your total shunt capacitance.

I don't know the capacitance of the Belden co-ax, but it's terminated like any other wire.  The shield goes to the ground (outside) and the center conductor to the male pin.  They even make crimp-on connectors but wire size is a consideration as is the thickness of insulation - overall size. 

Blue Jeans Cables has ready made interconnect that's 12.2pF/ft.  I've read that Emovita has cables with equally low capacitance.  So, if you run 20' of this stuff, you're cable capacitance is at least 244pF.  I don't know about the ET arm, I would guess it to be low, but what's the ModWright input capacitance?

Lets say worst case is 220pF.  With ET wiring total comes to 480pF ??   Not recommended, but it might be okay with Grado.
neo

http://www.bluejeanscable.com/store/audio/

BTW, I've used Blue Jean on phono and it sounds good to me.

[JackD]

Neo

I actually bought a pair of those Emotiva cables Wayner was raving about.  They measured over 200pf per meter.  Also if I remember what Marc told me the Grado will be O.K. until about 800pf, but that is just going from memory.  A 20ft pair of of the Blue Jeans cables are only $73, so worth a try at that price. 

[Wayner]

At least the Emotiva cables wont wreck your RCA jacks. There is more to a cable length then just capacitance, especially at longer distances. Shielding would be of the utmost importance, as long cables start to resemble antenna elements. Then there is the problem of driving a signal down the long cable, and one would wonder if the phono preamp has the guts to drive the cable length.

And at any rate, Emotiva doesn't offer a 20 foot long cable. Their lengths are .5, 1 and 2 meter.

Also, here are the specs from the Emotiva website:

Solid brass machined ends with 3 micron thick gold plating.
Nylon braided anti-scuff jacket over PVC outer insulator.
100% double shielding using a solid mylar wrap overlaid with tin-plated, oxygen-free copper braiding.
Nylon insulated oxygen-free stranded copper core.
Soldered ends of the cable are covered with an injection-molded subchassis to provide a durable, corrosion-resistant, lifetime connection.
75 ohm characteristed impedence. Cable geometry optimized for high speed digital audio and video.
Impedance: 75 ohm, capacitance: 61.64 pf/m.
Sold individually.

I should note here that my cables measure higher then the published data. I still like them.

[Speedskater]

Interesting. Not sure how to terminate Coax with an RCA, but maybe I can figure it out.

You can buy them with connectors at any length you like from:
Blue Jeans Cable or some other supplies.  Chose a co-ax with from 12pF to 16pF per foot.
http://www.bluejeanscable.com/store/subwoofer/LC1-design-notes.htm

[/quote]
How much of a high frequency roll off/loss is there? Is there a formula to calculate based upon capacitance per foot?
[/quote]
It's not about high frequency roll off.
Every moving magnetic phono cartridge has it's own sweet-spot of total load capacitance. That's the total of interconnect and pre-amp input stage capacitance.

Maybe someone can find a reference article.

[JackD]

wayner

Didn't say they didn't sound fine, they do.  But as you noted they are not what they are spec'ed and mine are 3x the figure listed.  So I would not use that type of cable between the TT and phono stage.  Anywhere else is fine.  I would suspect that the ones Emotiva got in the first batch probably did meet spec, but the supplier has substituted cable type since.  Even if the OP bought the Belden cable and connectors and did it himself, I doubt he would get it much cheaper.

[SoCalWJS]

Thanks to your Grado you might get away with it relatively unscathed.  I assume this a HO Grado going into a MM phono stage?

The output of a cart has inductance which in combination with the capacitance in question effects the response.  All HO Grados have 45mH inductance, very low for a HO.  The bad news is that the capacitance of the cable is added to the that of the internal tonearm wire and again to that of the preamp input.  The sum is your total shunt capacitance.

I don't know the capacitance of the Belden co-ax, but it's terminated like any other wire.  The shield goes to the ground (outside) and the center conductor to the male pin.  They even make crimp-on connectors but wire size is a consideration as is the thickness of insulation - overall size. 

Blue Jeans Cables has ready made interconnect that's 12.2pF/ft.  I've read that Emovita has cables with equally low capacitance.  So, if you run 20' of this stuff, you're cable capacitance is at least 244pF.  I don't know about the ET arm, I would guess it to be low, but what's the ModWright input capacitance?

Lets say worst case is 220pF.  With ET wiring total comes to 480pF ??   Not recommended, but it might be okay with Grado.
neo

http://www.bluejeanscable.com/store/audio/

BTW, I've used Blue Jean on phono and it sounds good to me.

Thanks for this and everybody's input.

Leaning towards ordering the Blue Jeans RCA's as a reasonably priced solution and give it a shot and see how I like it.

Thanks again! 

[Wayner]

wayner

Didn't say they didn't sound fine, they do.  But as you noted they are not what they are spec'ed and mine are 3x the figure listed.  So I would not use that type of cable between the TT and phono stage.  Anywhere else is fine.  I would suspect that the ones Emotiva got in the first batch probably did meet spec, but the supplier has substituted cable type since.  Even if the OP bought the Belden cable and connectors and did it himself, I doubt he would get it much cheaper.

I forgot to mention that I buy the digital series for all of my phono preamp use. These cables are coaxial designs, whereas their other analog cables are twisted pairs. These digital cables are 61 pf per cable assembly (1 meter), which includes the RCA connectors. The Bluejeans cable spec is for the cable only and does not include the RCA connectors. I remember measuring a cable of Bluejeans (again 1 meter) and it was about 68 pf.

I got rid of all of my Bluejeans cables because: 1) They wrecked an RCA out jack on one of my tuners, and 2) I thought the bulk of the RCA connector was too massive, even for their own connector, which is a two part system. After a period of time, the connectors would sag and cause occasional mis-connections. That is why I switched to Emotiva. That said, I also bought some 1 meter AudioQuest Evergreens for some of my other tuners, which I like very much as well. If I were to do it again, I might have bought all Audioquest cables.

For shits and giggles, I just measured a very highly regarded cable of the day, the "Z" series from Monster cable, and a 1 meter pair measured 356 pf. I also measured a pair of 2 dollar Recoton cables (1 meter) and they were 92 pf.

I certainly didn't intend to hijack the thread, but unusual phono cable distance problems have come up before, and there are several risks here. At distance like this, I wonder if the OP shouldn't get a couple of CAT-5e baluns and turn his signal into digital from his turntable (and then back to analog), then go to the phono preamp. I know that PartsExpress has these and it will work for smallish voltages coming off of a phono cartridge.

Turntable---->analog to digital balun------>CAT-5e cable (20 feet long)----->digital to analog balun------>phono preamp would be the chain. No hum to worry about, no capacitance to worry about. However, for analog puritans, the signal did get change to digital and back............

Now where are those guys that say that digital is way better then analog.......

[neobop]

Neo

I actually bought a pair of those Emotiva cables Wayner was raving about.  They measured over 200pf per meter.  Also if I remember what Marc told me the Grado will be O.K. until about 800pf, but that is just going from memory.  A 20ft pair of of the Blue Jeans cables are only $73, so worth a try at that price.

Blue Jeans LC-1 wire is made by Belden with double copper braid shield.  Most of the video cable in Belden's catalogue is multi-conductor.
Blue Jeans is stiff though, and care must be taken that excessive pressure doesn't move a light weight component or mess up an RCA.  If Belden makes a single conductor co-ax with equally low capacitance and is more flexible, it might be a better choice. 

SoCal,
Sorry I mentioned Emotiva.  I read somewhere that capacitance is equally low.  It's probably excellent in other applications.

There's really no way to calculate the affect on high frequency performance.  The best you could do in that respect, is calculate electrical resonance at Hagerman site.  Do you know the input capacitance of the phono section?  If so, you can have a decent estimate of capacitance, but you really won't know overall results until you try it.
The problem is that mechanical performance overwhelms electrical in the overall scheme and electrical performance in this respect modifies mechanical. 
Typical MMs inductance range is from 300 -1000mH.  Too much capacitance with one of these will lower the frequency of high frequency resonance and augment response somewhere in the mid/treble region (brighter).  Above that peak it will roll off sharply.   Your Grado has 45mH and that's all the difference.  The Marc, Jack is referring to is a member here, BaMorin.  He probably knows more about Grado than anyone short of Joe.  I don't think capacitance will be a problem assuming your phono stage has reasonable capacitance.  If you want to try it first, get some caps and put them across your inputs. 
http://www.amazon.com/Silver-Mica-Capacitor-Guitar-250pF/dp/B004RPKJJ6/ref=sr_1_11?ie=UTF8&qid=1401058921&sr=8-11&keywords=silver+mica+capacitors

That's a mighty long run for a low voltage signal, but I think it might work. 
neo

[Speedskater]

How much of a high frequency roll off/loss is there? Is there a formula to calculate based upon capacitance per foot?

It's not about high frequency roll off.
Every moving magnetic phono cartridge has it's own sweet-spot of total load capacitance. That's the total of interconnect and pre-amp input stage capacitance.
Maybe someone can find a reference article.

I found the link:

http://www.hagtech.com/loading.html

[JackD]

One way to alleviate the stress from the stiffness of the Blue Jeans cables is to buy them a foot or so longer than you need them so that you can make a loop before you plug them into the TT and the Preamp.  This is done all the time with stiff power cables.  At the lengths were talking about another 20pf or so won't make a difference. 

[neobop]

Forget Hagerman.  With this cart and 500pF, electrical resonance is higher than 33KHZ. 

Ordering an extra foot or two is a good idea.  When you rearrange the room you can chop it up into smaller pairs.  I've used the cable for high level applications and it's good sounding neutral wire.
neo

[dlaloum]

Here is another vote for the BlueJeans LC-1 cables - that's what I use too... not overly flexible, but very low capacitance and well built...