2. amps-preamps
  3. 1414403520

Long cable run from my phono preamp to linestage.

Due to constraints of a small 11 x 12 ft listening room and the difficulty accessing my turntable within a vertical rack, I've decided to place my turntable on a small table next to my listening chair. As this setup requires a 4 meter cable run between my turntable and full function preamplifier, I've decided to use a small stand alone phono preamplifier with 68db gain (MC) to sit next to my turntable. I am not terribly experienced with analog. Is it ok to use a 4 meter cable run between phono preamp and linestage? I'm sure it's better than sending an unamplified MC signal over 4 meters of cable to my full function preamplifier. Please note I do not have sufficient room to place my full function pre or my entire rack near the listening chair. Thanks for your opinions. Perhaps I'm overthinking this :))
audiobrian
schubert
4,867 posts
 
I've done it, no bad effects I ever noticed .
Of course audio is a trial and see affair.
almarg's avatar
almarg
8,673 posts
 
What model is the phono preamplifier?

Doing what you propose will often and perhaps usually be fine, but it depends on the output impedance of the phono preamp (the lower the better), the capacitance of the cable (the lower the better), and the characteristics of the shielding in the cable. Susceptibility of the phono preamp and the main preamp to ground loop issues (which is generally unpredictable), and whether the interconnection is balanced or unbalanced, can also sometimes be relevant factors.

Regards,
-- Al
viridian's avatar
viridian
4,184 posts
 
I would add a couple of things to what Al said. The ratio of the output impedance of the phono preamp to the input impedance of the linestage should generally be at least 1:10 and preferably 1:20 though there are certainly exceptions and otherwise fortuitous combinations that don't meet these criteria.

All is not lost if you have problems. A buffer can be installed at the output of the phono preamp to drive the long cable run. Yes, it's another box and another set of interconnects, but sometimes this is the only panacea in these situations.

Another concern with long cable runs can be radio frequency interferance, and this can be a bit harder to cure. Certainly, you should use a sheilded interconnect for runs of that length at the least.
dkarmeli
332 posts
 
Don't worry about it 4 meters is nothing with most cables, I have 6-8 meter runs between the phono and pre for years.

david
georgehifi's avatar
georgehifi
4,966 posts
 

Almarg is right Audiobrian, to get the best out of it we need to know the output impedance of your phono stage first.

Then I will calculate for you the maximum capacitance of 4mt interconect you should use, as it will roll off the highs a bit if not right, which Dkarmeli may be doing without even knowing it.

Cheers George
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