Guys,

Ok, here's the situation. Since my setup is based solely on equipament with stereo outputs (synths, modules, drum machine, etc.), my current signal chain is:

All Equipment > Rolls Line mixer > EQ > Amp > Monitors

I'm trying to hookup a Bass POD (mono output) to this systems, obviously if I connect it to the line mixer (only stereo inputs), I get a audio in only one side.

I see two options.
(1) Getting the stereo signal from the headphone output from the POD into the stereo input of the line mixer.
(2) Getting some kind of "Y" cable from the 'model output' of the BASS POD, so that the signal gets split between both inputs of a stereo input in the line mixer.

I do have a TASCAM mixer that has 4 stereo and 4 mono inputs (that I'm not using right now), that I could use between the line mixer and the POD, but that's just adding one more component to the signal chain.

Opinions? I am missing an easier solution?

Rod, it's OK to distribute the mono output from the bass pod to both the left and right inputs of the mixer.

No harm in doing this. Just get the Y cable you mentioned.

Tom

Doesn't the Rolls Line mixer had the ability to pan or center the signal? If so I would think "center" would send it to both sides.

Doesnt't work. When you pan to the one side, you get the same thing (signal on one side only), when you pan to the other, there's no sound.

Cool. Now I just have to get the cable... will try it out this weekend.

That seems like the easiest solution

Another related question, if you don't mind:

What's the best way to hook up my keyboard or mixer (both with unbalanced stereo L/R outs) to my powered speakers' balanced inputs. Is a DI box necessary?

No DI necessary. Just plug in.

No, its not unless you get hum. However by going unbalanced you lose 6db of gain which may (probably won't) make it hard to get the volume you want.

Thanks for bearing with me ...
So even though the L/R outs of the Electro are unbalanced, I can run balanced TRS cables from the board's outs to the XLR inputs of the speakers, with no adverse effect on either piece of equipment?

No problem. When you plug balanced (i.e., TRS) cables into an unbalanced (TS) jack, one side of the balanced signal will be connected to ground, so the signal will not really be balanced - thus you don't gain any of the balanced advantages (less noise, higher signal level). However, it won't hurt anything - balanced inputs are "floating" with respect to ground, so grounding one side doesn't hurt anything.

- Bob

Thanks Bob, so a final question then:

What's the optimal solution (cablewise) to get the adavantages of a balanced connection when hooking up a keyboard's L/R unbalanced outs to a pair of powered speaker's balanced XLR inputs for stereo?

I wouldn't do that. I would use an unbalanced cable. While what you suggest should, and usually will, work, you are relying on the ring making a good connection to the ground on the plug. A TS plug can make a connection anywhere along its length, but you need it to make a connection in the smaller length of the ring. Once in a while you will get a poor connection.

The optimial solution is to use an isolation transformer of active DI between the two units. Or a small pre-amp, which can also juice up your sound if its a tube pre-amp.

I guess it depends on the definition of "optimal." If the connection works - no induced hum, and strong enough signal (which most of the time can be compensated with a little extra twist of the volume control at the receiving end) - then it's optimal enough. A passive DI box has a transformer that converts the unbalanced to a balanced signal - but then there are the imperfections that might be introduced by the transformer. An active DI uses electronics to do the same, but requires a power source, and may produce imperfections of its own. All of these imperfections are very slight, likely imperceptible. But most of the time so is the direct (mismatched) connection, so in the interest of KISS ("Keep It Simple Stupid"), I would (and do) just connect the two and not worry about it.

- Bob

Thanks immensely for your help, guys. Looking back, I should probably just have asked how you folks who play live generally connect your gear, and taken it from there...

Cliffk (and anyone else):

If you're interested, tweakheadz.com has a nice little primer on the whole balanced/unbalanced thing. Scroll about two-thirds of the way down on the following link: TWEAKHEADZ

Noah

What a great page. Well worth reading.

Thanks NoahZark, Tweak is the bomb. I also found this page quite useful.