it seems some poweramps take a balanced input but there are several preamps with an unbal. out - Aguilar DB 659 is one. what if an unbalanced signal is run into a 1/4" TRS input on a power amp ?
Plugging an unbalanced 1/4" connection into a balanced 1/4" connection works fine. You just don't get any noise rejection.
I would say that plugging an unbalanced cable into a balanced input usually is fine. On _RARE_ occasions the input is not designed to handle an unbalanced input. This may result in damage to the input. You should check with the amp manufacturer just to be sure.
so, could you run an instrument cable from the preamp to power amp? just curious, but how's a TRS cable different from a speaker cable?
TRS means tip/ring/sleeve. This is typically used for balanced or stereo cable. This designation has to do with the structure of the connector itself, which is a stereo phone jack. (TRS connectors have two dark bands.) Speaker cable means unshielded insulated cable designed to handle the high power flow of an amp output. This is usually heavy guage 2 conductor wire. There are 4 conductor and 8 conductor versions as well that I know of. The connector is commonly one of 1/4" mono phone jack, banana plug, speakon, XLR, strip wire, spade connectors, or other lesser known types.
