Unbalanced inteconnects - how long?

[Lisandro_P]

Well, i'm finishing the layout of my new hifi system (pictures coming soon!). Now, i wanted to keep the class-A poweramp high (right next to the speakers) and away from the rest of the equipment, which sits on a nice wooden shelf.

I wanted to usea an unbalanced RCA stereo pair cable, carrying 1v P-P signal, to conect the preamp to the power amp. This cable would have to be almost 4 meters long in order to reach the power amp and be able to hide it in cable guides.

Is this acceptable? Should i place the power amp with the rest of the gear and use long speaker cables? Or go balanced? It might sound silly to ask, but i have to know if i'll need to hack a balanced send / receive now, before i put it all toghether.

[audiopro]

Assuming a reasonably low output impedance from your preamp, 4 metres should pose little problems. Just try to use a low capacitance cable, and keep the interconnect away from ac lines. That's much preferable than a long speaker cable

[Lisandro_P]

Actually, impedance doesn't worry me. It's noise. Even when shielded, i'm worried that long cables might pick up enough noise to be audible. Specially in the proximity of power wiring.

[pinkmouse]

Make sure your output buffer, (I like AD811 for the job), has plenty of bypass capacitance, and provided you don't live in an electrically noisy enviroment you should get up to 10m or so.

If you're not running an output buffer, you really don't want to go over a couple of metres.

[pinkmouse]

Ah, if it's noise you're worried about, then go balanced from the start.