Mixing desk into amp/mixer

[rossmc]

Hello all,

I have some experience attempting to do sound for some local gigs, mainly through hired systems. I have been asked to try and setup a rock/pop gig in a school hall in Feb.

 

After looking at the kit they have my options are a little more limited than usual. They have a Carlsbro 150W PA system, the PA amp and mixer are a built in unit. Would I be able to get away with the correct leads plugging in a 16 channel Allen + Heath mixing desk I have into one of the inputs on their PA amp/mixer combo? Basically using the combo unit in place of a power amp and using the A+H mixer for mixing mics?

 

 

Thanks,

rossmc

[J Pearce]

Yep, I do this quite regularly.

 

Just take the line outs from your desk, and plug them into the stereo line inputs on the combo.

 

Watch out for balanced/unbalanced issues though.

[rossmc]

:)! Glad to know I'll atleast have some luck as I'm not having any with the owners of the school (private company\public partnership).

 

Who installed a 32 channel mixing desk, 2 power amps (600W system) and thought the school tech was joking when he said the 2 wedge monitors (100W) they provided were adequate for loudspeakers. Fun and games!

 

Am I right in thinking I need a lead with 2 jacks on one end and 1 jack on the other in order to get the correct output from the desk? - Stereo balance? Sorry for my ignorance, I'm still learning unfortunately and have no proper training other than my own tinkering around !

[J Pearce]

Depends on the inputs available, and if you want the system in stereo or mono.

[Rob_Beech]

you would have to expand a little on this last bit.

 

Its important that you get this right or you could have some interesting results.

 

If this is a stereo pa system then you would need an output of the left channel on the desk into one channel on the calsbro unit. then the right output from the desk to another. simply pan the left channel left and the right channel right on the calsbro combo.

 

If it is just a mono combo then just use both outputs seperatly. if you only have 1 input available on this combo DO NOT try and use a Y lead to join two signals together. the low Z out of the right hand channel on the desk would get driven by the left channel etc. particularly with high Z inputs on the combo.

your best bet in this case is to just use a mono out on the A&H board if it has a seperate mono out. Failing that just use th Left or Right out.

Remember if you do this then dedicated stereo inputs may need special routing to get both channels.

 

What A&H desk were you thinking of using.?

 

Rob

[rossmc]

After some googling the PA powered mixer is a Carlsbro Marlin 1500 (which output method from the desk would you recommend?) , shall check the model of the A+H unit when I have a look at things again tomorrow!

 

All inputs on the desk will be from Shure 57+ 58's, an AKG kick drum mic so nothing special? There may also be an input from a laptop/ipod for background music during band changeovers.etc.

 

Multicore within the hall is extremely poor, is it really that bad to run from the amp (PA power mixer) to speakers over XLR multicore? Or perhaps between the A+H desk and PA head. I.e A+H at rear of hall, PA head on stage.. Or am I just asking for trouble and lots of loss? I'm not too keen on having to mix from the side of the stage however.. Hope this makes sense!

[Rob_Beech]

if you have a multicore there you would put the A&H desk at th back of the room, and then the carlsbro head at the stage. You should NOT by any means run speaker level signals down a multicore. Its VERY bad practise anyway but with a multicore the cable is thinner still. This will not handle these types of signals. Hopefully you should have enough inputs on the A&H board. with this level of pa system I cannot see any more iputs that whats on teh board being practical anyway.

 

IIRC the marlin 1500 is 150watts mono. so take left and right out of the desk into 2 channels on the head.

 

Remember its better to have a little clean sound that alot of horrible distorted sound. Its quite possible that you'll not have alot of headroom with this system!

is it not possible to hire racks and stacks? it appears you have a suitable desk and the mics etc.

[rossmc]

Ok thanks for that, shall have a look today at how feasable it is to run on te multicore between back and stage..

 

Number of inputs should be fine for the job, mainly vocalists but one band has a brass section which needs some micing up. Drumkit may been fine without mic due to the depth of the stage area/room but I was going to mic up the kick for that extra presence.

 

Of course! I'm very tempted to try and set it up similar to how it will be on the night to check it's all going to work. I agree things are unfortunately very tight. I usually hire in Fohnn 2kw systems from SteveR for this kind of gig, but due to budget (for charity) I don't think it'll be possible and I'm stuck with what kit they have lying around..

 

A&H desk is an older model - GS1 with meterbridge. There is a mono output on the back of the desk in the format of an RCA, there is also an RCA > 2 XLR adaptor with the desk..

[RumbleO]

IIRC the marlin 1500 is 150watts mono. so take left and right out of the desk into 2 channels on the head.

As it's mono, just run one channel from the desk to the head.

Pan everything centrally, and run your main output from, Left, or Mono, or 'A' to the Carlsboro.

What model 16 Ch A+H desk is it?

 

Edit: Too slow - OP answered "It's a GS1 " while I was typing.

 

The mono output on the GS1 is after the subgroups and you'd be controlling from the group fader..

 

Easier to run from Left Main Out (imho)