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Multiple Inputs in One Shielded Cable?

I'm building a stereo SE EL84 amp with a pair of inputs near the back. The input tube is at the front so I'll run the signal up there in shielded cable. I did the same thing in my KT88 monoblocks and it works great. No radio stations or hum even with several inches of wire between the jack and the tube.

So now with stereo I have two jacks at the rear. I have some five conductor shielded cable. So- am I likely to run into problems if I put both inputs in one cable for the run up front? I'll have one wire unused in the cable? I haven't pulled the wires out to check but they appear to be gently twisted, maybe one twist every two inches.

I may just give it a try since I'm at the point of soldering it up but if there are problems it may help to know what to rip out first!
kmtang said:
The individual wires should be shield separately as well. If not, it will cause cross talk between the wires.


I thought that might be the case. :( How significant an issue do you think the cross-talk would be? I do have plenty of two conductor shielded cable so I could run two separate lines easily.

This amp is a learning experience for me. I've now built kits, a couple scratch-builts using schematics from others and now this with my own schematic. I don't expect it to be perfect but I would like to avoid gross mistakes (and explosions/fire/electrocution etc.).


Paid Member
2003-06-12 7:04 pm
Maine USA
> How significant an issue do you think the cross-talk would be?

Depends entirely on the source impedance.

In this case, I would just use two cables.

FWIW, I do have installations running hundreds of feet of cable, some of it not even shielded. But the source impedance is very low and the source separation is low to begin with. I did the math at the time and was happy for that situation. But I don't think I would do it that way inside a hi-fi amp if I could afford and fit two cables (one per signal).