Splitting input source - nightmare

MphisChris

New Member
Hi everbody! Sorry for the super long first post, but I am having problems splitting audio line level connections to seperate amps to power floor speakers and subs on my home stereo.

Basically, I have a dj style stanton mixer/preamp and i am trying to split the signal to two different amps. There is an old '70s SS mcintosh amp with RCA inputs to power some B&W speakers, and a mid 2000 crown power amp with XLR inputs to power some random L7 15" car subs. My problem is no matter how I try and split the signal from the mixer, whenever I use both amps at the same time, the crown amp will work and the McIntosh amp play silence. I figured all line level inputs were the same, but here is the deep dive i guess. I am using a 1/4 inch to xlr cables that I have tried to connect to both the rca output and the 1/4 output from the mixer. It has both options listed as record and output level which is probably the same thing. I would like to split the rca output, but even if I have the crown on the 1/4 output and the McIntosh on the rca output, I still get no/inaudible signal from the mac, while the crown just bumps away.

I have tried to research this best I can to find two issues that could be possible. First guess, assuming some line level inputs work on high independence and some one low, and that even though nowdays everything can work together, maybe in the 70's the Mac doesnt like the combination of input independence? Second guess, is that the 1/4 to xlr cables are including the random other channel that makes the cable balanced, and that the inclusion of the inverse signal (term?) cancels out most everything given to the mac and makes everything inaudible? I know that both amps work when plugged in independently, but the only way I can get both to work together is to use the headphone output on the mixer to power the crown amp. I think it works because the headphone output on dj mixers have their own gain and input selection which would make it a whole other channel.

Obviously, the weak link in my system is the $60 dj mixer, so I am looking to upgrade that at some point. (I currently have a bottlehead mixer to use, but that is a whole another issue). When i upgrade to the bottlehead, I wont be able to use the headphone output, so I am hoping for some sort or solution to use both amps when attached to an rca splitter. I know that an rca splitter will lose some db, but it should still have some input on both sides.

Do any of you audio guru's know what I am doing wrong?
 
Have you tried running the Mac alone? How do you know that it works?

Model numbers and some pictures of the connections on the back of your units may get you better responses. ;)
 
Yes. The mac works when plugged in alone and when the crown is on the headphone output.

Gear:
Crown xls402
McIntosh 2100
Stanton Sk6

I'll look into how to post pictures, as I just took some that show how the xlr cords are made. There are only two sections on the 1/4 cable so I know that it is not balanced, but I'm a little more confused how it could be made another way? One signal is going to pin 2 and then pins 1,3 and top ground are all together on the other signal wire.

Does anybody see anything off with that? Or maybe other things I should check?
 
Not sure I've totally got my head around this problem, but I do have some experience with mixers.

1. I can't see that there's any reason the 1/4 outputs need to be used at all.
You can definitely use the 1/4 master outputs but you're feeding one amp with RCA inputs and another with XLR's.
This just complicates things.

2. Use the RCA master outputs only and add "Y" splitter/connectors to both. One male into two females.
And no, the Record outputs on that mixer aren't the same thing at all.

3. Using the Y connectors, run one set of RCA cables to the McIntosh.

4. Run the second set to the Crown, but of course you'll need RCA to XLR adapters to do so.

5. I'll be very surprised if that doesn't work.

As an aside, I've yet to use a powered DJ-type mixer that doesn't add hum.
For a home set-up, you're better off with preamp and perhaps a switch-box.
 
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I am not familiar with your specific preamp/mixer so this is just a wild hunch. It is possible that the 1/4 jacks (when the male is inserted) automatically cuts out the XLR. There may be a design reason for doing this, possibly having to do with impedance matching. Using both the 1/4 “ and xlr at the same time may create an impedance loading that is too large for the preamp. Again this is just a hunch. Try running the xlr separate and then insert the 1/4” and see what happens.
 
I think you get what I am going for. I'm only 1/4 cables because that is the cable that I had before to convert to xlr. Now i use an rca to 1/4 adaptor to allow the 1/4 to xlr cables to work (Im to cheap to buy new cables).

I tried to split the rca like you said but for some reason it doesnt work for the mac. I think it has something to do with using a balanced cable (xlr) with unbalanced ones (rca).

I am going to try and eliminate the mixer as the issue by playing music from my phone and splitting that between the two amps with the same rca splitter set up. If that doesnt work, then I am going to resolder my 1/4 to xlr cables to remove the negative wire from pin 1 on the xlr and see what happens.

Sorry for the delay in pictures. I know that will help..
 
Guys. I think I figured it out for now.

I tried to bypass my mixer and nothing was acting right when i started using my y-adapters and rca to 1/4 adapters so I think that is my problem. I bought both if these brand new online so I am surprised that they crapped out instantly :/

Sorry for making the longest post ever about using quality adapters. I'll buy some new ones and see if that fixes the issue
 
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