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Turntable long cable run

10775 Views 19 Replies 9 Participants Last post by wizzack, Mar 7, 2014

Yardl3y

Discussion Starter · Feb 23, 2014

2

Hi all, I'm going to be picking up a Pro-Ject Debut Carbon Turntable tomorrow! Very excited! I'm going to be running it through an ART DJPRE II Phono Preamplifier into my Onkyo HT-R380 receiver.

Right now I have my cheap Sony TT going from phono to 3.5mm with one of these

Then a long (about 20 foot) 3.5mm cable into the front Aux input of the Onkyo. I actually just set this up yesterday for testing purposes. I want to know if this is a good idea. It sounds ok, but I'm I loosing quality? I'd hate to upgrade to the nicer Pro-Ject TT and not utilize its full potential.

With the Pro-Ject TT I'd be going in to the ART DJPRE II with a short phono cable, then using one of these

to attach the 20foot 3.5mm cable from the ART DJPRE II into the Aux of the Onkyo.

Any thoughts?

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commsysman

· #2 · Feb 24, 2014

Keep the unbalanced (RCA) cables from the turntable to the phono preamp as short as possible; no more than 2 feet maximum. That is the most critical thing.

The cables from the phono preamp to the main amplifier are much less critical, but 20 feet is very long for unbalanced cables.

It will be best if those long cables are also a regular pair of unbalanced RCA-to-RCA cables; forget the 3.5mm adapters/cables.

You have 5 pairs of RCA audio input jacks (Labelled TV/CD, Game, etc. etc.) on the back of the receiver; use one of those for your phono input point.

There is a potential for hum and/or noise to be picked up by the long cables.

Try to keep them as far away from power cords and other wiring as possible and pray...lol.

BTW- Monoprice #2866 is a pair of 25-foot RCA interconnect cables with gold-plated connectors; less than $10.

P.S.- If you want better sound quality, invest $99 in the NAD PP-2i Phono preamp.

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IntelliVolume

· #3 · Feb 24, 2014

You know, it's funny I stumbled upon this thread because I will most likely be in a similar situation soon...

I'll be adding a new turntable to my two channel rig at some point soon (most likely the Audio-Technica "Technics 1200" clone; I wanted a 1200 but since they've been discontinued by Panasonic, the prices on them are off the wall) but because it's going to have to sit at the top of my Bell'O glass-shelved audio tower, its RCA connections to my stereo receiver I am guessing are going to have to be quite long...possibly longer than what Audio-Technica supplies in the box with the turntable...

Are there any recommended "RCA extension" cables on the market that could possibly help me?

commsysman

· #4 · Feb 24, 2014

The signal voltage from the cartridge is much too small to run through long cables; hum and noise will be a major problem if you just extend the turntable cables. You can't do that.

They make them short for a good reason.

There is another serious problem too; the capacitance of the long cables will be so large that the frequency response of the cartridge will be disastrously altered and it will sound like crap.

The only way to do it is to use short cables(under 2 feet) to a dedicated phono preamp, which will boost the signal by at least 100 times, and then run longer cables from the phono preamp to any regular line-level input on the receiver.

IntelliVolume

· #5 · Feb 24, 2014

Quote:
Originally Posted by commsysman /t/1519472/turntable-long-cable-run#post_24403594

The signal voltage from the cartridge is much too small to run through long cables; hum and noise will be a major problem if you just extend the turntable cables. You can't do that.

The only way to do it is to use short cables(under 2 feet) to a dedicated phono preamp, which will boost the signal by at lest 100 times, and then run cables from the phono preamp to any regular line-level input on the receiver.

Thanks Commsys,

I definitely have a dedicated "PHONO" input on my Onkyo 8555 ready to accept the input from the turntable; but it's the length of the cables that concerns me -- if I did want to experiement with a longer cable run, do they make an "RCA extension" patch?

commsysman

· #6 · Feb 24, 2014

Quote:
Originally Posted by IntelliVolume /t/1519472/turntable-long-cable-run#post_24403610

Thanks Commsys,

I definitely have a dedicated "PHONO" input on my Onkyo 8555 ready to accept the input from the turntable; but it's the length of the cables that concerns me -- if I did want to experiement with a longer cable run, do they make an "RCA extension" patch?

You can certainly buy a cable extension.

BUT you can't connect a cartridge to such a long extended cable!!! That is a NO NO NO-NO!!

The longest cable that can be directly connected to the cartridge is maybe 3 feet, at the longest.

Again, the excessive capacitance of the extended cable will ruin the sound quality of the cartridge; YOU CAN"T DO THAT!!!!!!!!!!!!!

You will have to put a phono preamp near the turntable and then NOT USE the PHONO input on the receiver.

The output of the phono preamp will have to connect to one of the other inputs of the receiver.

(if you look at the specs for the cartridge it will tell you the maximum capacitance it can be loaded by; a long cable will have way more capacitance than is allowed)

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IntelliVolume

· #7 · Feb 25, 2014

What do you mean by "connecting a cartridge" to a longer cable? I'm referring to the RCA connectors coming out of the table that connect to a preamp/receiver's PHONO IN jacks...

Do you mean lengthening THESE cables will affect the CARTRIDGE'S performance?

jdcrox

· #8 · Feb 25, 2014

Actually, yes they certainly can. Phono output is an extremely low signal, very susceptible to picking up noise. And affected by capacitance, impedance, etc of the cables also more than high-level signals. You do not have to get fancy with cables, but best to keep them as short as possible to the phono pre-amp.

And to add, you are "connecting the cartridge" directly to the Phono in, since that is what attaches to the RCA cables!

FMW

· #9 · Feb 25, 2014

You need to bring the turntable closer to the amplifier or the amplifier closer to the turntable. A six foot RCA cable would be OK but 20 feet is very risky.

Yardl3y

Discussion Starter · #10 · Feb 25, 2014

Thanks for the help guys. I know 3.5mm is not ideal but I really can't drill holes big enough for RCA throughout my house. I'm waiting for my pre-amp to come in today so I can finally test, will let you guys know the results. Although my current TT with built in pre-amp is hooked up in this way and sounds fine. I tried it closer to the receiver and couldn't tell the difference.

IntelliVolume

· #11 · Feb 26, 2014

I'm admittedly lost, gentlemen; I don't understand how a phono CARTRIDGE plugs into RCA inputs of an amp, preamp or receiver...

Putting that aside for a moment, the cable run that I would need between the turntable and receiver would NOT be as long as 20 feet -- the table will sit atop my audio rack (a Bell'O audio tower with glass shelves) and the stereo receiver it is going to feed sits on the next to the last shelf down...so we're talking just a few extra feet over what's supplied in the box...

mcnarus

· #12 · Feb 26, 2014

Quote:
I'm admittedly lost, gentlemen; I don't understand how a phono CARTRIDGE plugs into RCA inputs of an amp, preamp or receiver...

A turntable is just a mechanical device that turns a record. The signal passes from the cartridge, down wires in the tonearm, to the cable connecting to the phono preamp. The turntable itself is not in the signal path.

Quote:
Putting that aside for a moment, the cable run that I would need between the turntable and receiver would NOT be as long as 20 feet -- the table will sit atop my audio rack (a Bell'O audio tower with glass shelves) and the stereo receiver it is going to feed sits on the next to the last shelf down...so we're talking just a few extra feet over what's supplied in the box...

So it might work just fine, or it might not. Best to try it out. If you have problems, get an outboard phono stage.

Stanton

· #13 · Feb 28, 2014

Just looked through this thread and it seems that a key item was left out: the GROUND wire! Not saying that long RCA/phone cables aren't a problem, but the killer will be the GROUND wire as it is guaranteed to inject hum if you have to extend too far.

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IntelliVolume

· #14 · Feb 28, 2014

Stanton,

That's a very interesting note -- I was thinking about the ground wire too and neglected to bring it up in this thread...

Yes, the ground wire would be a problem in my setup as well because of where it would have to reach...

Darn it...

wizzack

· #15 · Mar 2, 2014

I might have to run a 10ft rca/ground combo to my preamp. What's the best wire to use for a ground? Would well insulated 12g speaker wire be good?

Stanton

· #16 · Mar 3, 2014

Quote:
Originally Posted by wizzack /t/1519472/turntable-long-cable-run#post_24429732

I might have to run a 10ft rca/ground combo to my preamp. What's the best wire to use for a ground? Would well insulated 12g speaker wire be good?

You can probably go smaller (bigger gauge) as I suspect 12 gauge is much larger than your existing GND wire, but it really won't matter because you're going to pickup hum with that long of a run.

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wizzack

· #17 · Mar 4, 2014

Dang. Guess I'll start scoping out an inexpensive phono stage to add in the mix. Thanks.

Ratman

· #18 · Mar 4, 2014

I'd test before going to the expense of additional hardware.

FWIW... I used cheap RCA extenders from Radio Shack and a hunk of 16 AWG speaker wire(approx. 6') for the ground. No problems after 15 years.

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commsysman

· #19 · Mar 4, 2014

The ground wire would only have to reach to the ground terminal on the phono preamp.

The size of the ground wire is not critical, as it carries no current. It can be very small.

The Pro-Ject Box MM is a good phono preamp for a reasonable price.

Look at "Budget Phono Preamps" at Needle Doctor.

Quote:
Originally Posted by IntelliVolume /t/1519472/turntable-long-cable-run#post_24422605

Stanton,

That's a very interesting note -- I was thinking about the ground wire too and neglected to bring it up in this thread...

Yes, the ground wire would be a problem in my setup as well because of where it would have to reach...

Darn it...

Reactions: 1

wizzack

· #20 · Mar 7, 2014

Quote:
Originally Posted by Ratman /t/1519472/turntable-long-cable-run#post_24437310

I'd test before going to the expense of additional hardware.

FWIW... I used cheap RCA extenders from Radio Shack and a hunk of 16 AWG speaker wire(approx. 6') for the ground. No problems after 15 years.

Good to know I'll check it out. Small world, greetings from Pennsauken!

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