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Using smaller sound devices through an old PA

J

jjhardy

Mar 11, 2007
137
1
#1
If this has been a subject which has been discussed often, then sorry for not searching (don't know what terms to type in). I've recently acquired an old Sunn SR-4100 powered mixer, and it has worked fine so far with mics and instruments. However, when I plug in smaller items such as an Ipod with a cable with 1/8 in. and 1/4 in. male ends, the volume is extremely low. I've seen people plug Ipods into newer PA's without any problems.

Is the mixer too old to be able to play things with a headphone output, or am I missing something that could allow me to do this?
 
#2
jjhardy said:
If this has been a subject which has been discussed often, then sorry for not searching (don't know what terms to type in). I've recently acquired an old Sunn SR-4100 powered mixer, and it has worked fine so far with mics and instruments. However, when I plug in smaller items such as an Ipod with a cable with 1/8 in. and 1/4 in. male ends, the volume is extremely low. I've seen people plug Ipods into newer PA's without any problems.

Is the mixer too old to be able to play things with a headphone output, or am I missing something that could allow me to do this?
Click to expand...

The only fix I can think of is a DI box.
 
#3
I suppose you have already made sure that the volume wheel on the ipod is at max? Also on the mic pre, there should be a gain/trim, have you tried adjusting that clockwise to the desired level?
Should be ok, I don't think anything has radically changed from then to now ie. mic pre amp gain from 1/4" inputs. Maybe you plugged it into the insert instead of the input? I made a 1/8" to XLR adaptor, and plug it into all kinds/brands of mixing consoles, and if anything, its a hot signal.
 
#4
the volumes on the ipod, the channel it was plugged into and the mixer's master volume were all pretty much maxed out for me to hear anything coming from the speaker at all. i did try all of the 4 channels.
 
#6
Depends on how the specific amp/device was designed. A DI out is always balanced and may be at a wide range of output levels, but is typically supposed to be at "mic level" since it is intended to feed into a mic preamp. A "phone out" is typically unbalanced (though not always) and may be at any signal level just depending, again, on how it was specifically designed.
 
#7
jjhardy said:
the volumes on the ipod, the channel it was plugged into and the mixer's master volume were all pretty much maxed out for me to hear anything coming from the speaker at all. i did try all of the 4 channels.
Click to expand...

I had this problem- in my case it turned out to be that the cable was wired wrong for my application. Try switching the tip and ring connections at the 1/8" plug end, and use a cable tester to be sure there are no faults.
 
#9
Yes, cabling could very well be the culprit -- the most nominal cable to be running from your ipod would be a stereo 1/8" to TWO mono 1/4" jacks. Thus splitting the left and right channels.

Now for a condensed explaination of the theory...
There are two types of signals in PA applications. Balanced/Unbalanced.

Unbalanced - Cable has two wires and jack has tip/sleeve. One for positive/one for negative.
Balanced - Cable has three wires and has XLR jack or has tip/ring/sleeve on a 1/4".
Two for positive/one for negative.

Balanced connections are created to eliminate noise/crosstalk when transmitting signals/especially for long distances.
It acheives that by sending two different signals -- 1 cable would have the normal orginal signal, the second cable contains the original signal but with the phase reversed.
When it reaches the source, it flips the phase back and cancels out any noise added along transmission.

If you plug in a stereo signal into the inputs on your console, it flips the phase on one side becaues it's expecting a balanced input, not a stereo input. Effectively it cancels out any sound that would be the same on both the left and right tracks. Meaning it will sound pretty odd and will be a much lower level as you'll only be hearing partial sounds from effects/panning in the recording mix.

Make sense?
 
#11
it turned out the cable i was using before was faulty, so all is well now that i'm using a new one. and ben, that is some very informative advice i'll have to remember. More in depth than I need at the moment, as my goal is to just run circuit bent electronics through the mixer, but i'll remember all that about the cables.
 
#14
Ben-Jammin said:
Yeah, but you eliminate the phase issues. I figured he was trying to get signal -- not worried about stereo particularly.
Click to expand...
Hey, how did you go back in time to answer me? Do you have a time machine or something???

:hiding:

I guess as long as you're not listening to old Beatles albums with the hard panning it's OK, but it's a consideration IMHO.
 
#15
JimmyM said:
Ya, but if it's a stereo signal, won't you only get one side into the PA?
Click to expand...

You are correct, sir. He needs a splitter cable that takes the 1/8-inch TRS stereo output from the iPod and splits it to two 1/4-inch TS mono plugs which would go into two channels of the mixer. Otherwise, he's going to lose one side of the stereo image. If the board has RCA tape inputs, then he could use a splitter from the 1/8-inch TRS to two RCA plugs. Of course, someone else already said this, but I'm saying with the authority of over 18,000 posts.
 

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