Terminology 101 -
TRS = Tip Ring Sleeve. This refers to how the jack makes it's connection. The is a tip, a ring, and a sleeve.
RCA = The very same RCA that makes everything created this kind of jack. This type of jack only has a tip and a sleeve, although it is a bit different than a TP 1/4" TP connector.
Unbalanced = This is a audio line that has only 1 hot lead.
Balanced = This is a audio line that has two hot conductors that are 180 degrees out of phase with each other. To have a balanced line, the inputs and outputs of the devices participating in the signal must have OP amp that will take the signal and split it into two signals that are out of phase with each other, and also put it back together.
What is the difference?
A unbalanced signal will only have 1 hot lead and a ground lead. This type of signal is just fine except in environments where there may be a lot of RFI and AFI interference. But the signal will probably not be disturb at all if the cable connecting the two devices is less than 25 feet. The problem starts when a RFI or AFI signal is hot enough to bleed through the shield of the cable (often the shield is the ground lead also. Any signal that needs to not bleed to the hot lead needs somewhere to go, and ground is the perfect spot for it). With an unbalanced line, the interference will make it to the input of the next piece of equipment in line. This will cause radio stations to be heard, as well as CB radios, TV transmissions, etc......
With balanced lines, there are two hot leads that are 180 degress out of phase with each other. What happens if you are listening to two sources that are 180 degrees out of phase with each other? Well, you are not listening to it because the two signals will cancel each other out. So in the case of where a interference bleeds through a shield, it will attack the hot leads at the same time, in phase so to speak, and the OP amp at the next unit in line will cancel the interference out because it will only allow signals that are out of phase with each other to be heard.
Balanced line can usually run as long as 500 ft. without any problems. Although this really depends upon the quality of wire you are using. Long wire lines create more capasitance, which in effect acts like a transformer, which will phase SHIFT audio signal to a certain degree, more so at higher frequencies than low ones.
This is the very simple explaination.
Anyway, what that means for your amp (which is a Sampson, not a brand that instills a lot of confidence with me considering every one I have heard usually winds up blowing up speakers...maybe they are designing them better now) is that you can elect to feed the input of the amp with either a balanced or unbalanced signal, depending upon the equipment that you are hooking up to it, and/or the need to run very long lengths of wire to it.
If the equipment that you are inputting to the amp does not have balanced outputs, you can use the RCA unbalanced inputs on the amp provided that you don't need to run wire any longer than 25 ft. to get to the amp.
Also be aware that with some equipment, the balanced in's will accept a +4 signal, whereas the unbalanced will only accept a -10 signal. Check the manual of the device that you are plugging into the amp to see what it outputs.
Now, you are probably hooking your mixing board outputs to the power amp inputs. Some mixing boards only offer balanced signal output on XLR type jacks. This does not mean that you still can't hook these up to the 1/4" balanced inputs on the amp, it just means that you will either need some kind of adaptor that converts XLR to TRS, or need to make a cable that has the appropriate connectors on either end.
I would recommend hooking up as much of your equipment as possible in a balanced signal configuration. You will experience less troubles this way, as well as assure the best signal to noise ratio that is possible, which is one of the keys to better sounding recordings.
Good luck.
Ed Rei
Echo Star Studio
www.echostarstudio.com
[This message has been edited by sonusman (edited 01-18-2000).]
