Inputting two devices into an amp

OK, I should know this but I don't, and I did unsuccessfully search first. Help, please! Long post, sorry.

My bass amp is an Acoustic Image Clarus SL 4plus, and it has two BUFFERED inputs, so both can have something plugged in at he same time. Of course one is Hi Z and one is Lo Z.

The bass guitar signal comes in via a Sure wireless system receiver.

Likewise, I play a Casio CTK 7200 keyboard with two 1/4" outputs for stereo. I have "split" the keyboard, with bass "instruments" on the left hand half, and panned them mostly to the LEFT output. All the other things I play with the right hand/side/split (piano, flute, oboe, choral voices, Hammond) are panned to the RIGHT output, and will go to the PA. But I'd like the LEFT/bass signal going to my Clarus.

And I need to shift from the keyboard to the bass guitar and vice versa freely, usually mid-song, preferably with no other action required. And preferably with little noticeable volume change. Sometimes possibly tapping while chording. (While singing, no less.)

SO, IF I run both signals to the amp inputs, optimally which signal goes to which input?

I'd have to balance the keyboard output level to match the bass. So I'd adjust the bass for optimal output (90%ish on my L2K), set the amp gain and volume, and change the overall keyboard volume to get the bass and bass tones volumes to match. They can adjust the PA for the other (right ch) voices as needed once my volume is set. A minor setup activity for playing live.

-OR-

I have and could also use an N-audio MicroMIX MH400 4-channel signal mixer to run both signals to, and then run it's output to the amp. But then which amp input should I use?

That would allow me to adjust the keyboard volume independently, plus I can best use the overall keyboard volume to set the internal speakers volume to monitor what I'm doing, and adjust both downstream amplification system accordingly.

So for each case, which amp input should be used? Thoughts on the whole thing? Other options I should think about (preferably frugal and light weight ideas?) Thanks for anything you folks can come up with, I always get some great advice here!

Oh, one more little twist; sometimes I take an effects unit (Boss ME-50B.) In the first case I can run the wireless bass guitar signal out to and back from it first, but in the second case I could put it either there, OR between the mixer and amp to affect both signals. It doesn't seem to like being in the amp effects loop, the signal is probably too hot.

Here's the little mixer. It works well enough, once I tried running a bass and the keyboard mono output through it, and it sounded good; and neither pot was near the end of it's travel.


Thanks again!

 

Thanks, I can do that; I've actually got a sound dB meter. I'll just play the bass guitar/wireless without the mixer, and then with it to see where I have to set the mixer to get that same volume and just leave it there. Basicaly unity gain.

Then I can do the same with the keyboard set to my normal stage volume. And tweak that one until the two "basses" sound about the same when I play them. As long as it's a reasonable setting.

Worst case I can change the keyboard volume as needed. The other side going to the PA will be fine; the input gain we use now for the full, unsplit keyboard sound is right at mid scale already, so there's some slack.

Using the Lo Z input is what I most needed to know.

The Clarus has two unbalanced 1/4" inputs, not a balanced input. I was wondering which should be used OR to use a mixer. Sorry if I wasn't clear about that.

 

Thanks. The bass I understand, it was mostly the keyboard I was wondering about.

 

If it matters, I normally run the G&L L2000 in Passive. BUT, on this bass in particular the signal is fairly hot to begin with (hence the normal volume pot setting is at about 90% instead of full blast, many folks do this), and going to Active doesn't add a whole lot to that. There is also a third selection, an Active/Bright position on the switch, and it brings things up quite a bit more, but I don't use it for anything.

So as far as setting everything up for passive, I don't think going active on this particular instrument changes things so much that it should matter, despite what it does to the impedance; it's not any hotter of a signal than going full on the volume pot. When I do occasionally use active to highlight a section it doesn't seem to have any negative impact.

In fact, I believe that this works because the signal is hot enough that it allows me to plug into that line-level mixer beside a line-level keyboard input, and still have both play well together. I'm not having to raise the pot on the bass much higher than the keyboard to match. It looks like it works with the bass near 1 o'clock and the keyboard near 11.

I realize that there's a lot more going on regarding impedance and such, but volume and sound quality-wise it looks like it's going to work just fine.

Thanks again, folks.

 

I made up a little mount for the mini mixer to sit in my amp box, it tilts out a bit so straight plugs fit. Double-sided carpet tape holds everything down. The other two inputs are still accessible.







The silver box input comes from the wireless receiver, both plug in on the back The box houses the Fuhrman, a fan that blows on the amp, the power supply for the wireless, mixer and fan as well as some LEDs I can plug in to see this stuff, and a 25' 14ga power cord. It holds the speaker cables, some rags and other supplies, and not shown a plastic box with transmitter, lighting remotes, some cash, picks, jumpers, spare batteries, I put my wallet and keys in it, etc. A plywood cover with our logo snaps over the front, protecting everything inside.

Thanks again for the assistance!