Sound Problems - Can You Help Please?

[treen74 0]

Hello all,

 

Well its been a while .......and since i came to New Zealand (from Manchester,UK) Ive had my fair share of ups and downs (which I wont go into of course).

 

I brought all my equipment with me and have used it a few times in the garage with no problems.

 

I've managed to get my first gig in NZ - a wedding in the New Year in Auckland. I'm really looking forward to it - I'm very uptodate with all the must have tunes from this neck of the woods - added to this all the latest stuff one should have ..................

 

Anyway, today I switched everything on and ...................I can only get sound out of one side . I have 2 sets of speakers (JB Systems Pro 12 ,12" mids with horns and JBsystem Pro 12 15" subwoofers). Theres no problem with them as I swopped the wiring over and they work fine.

 

I'm not a techy in anyway so i'll tell you what I know -..................

 

There are two channels on the Amp - A & B. Channel B seams to be working fine. So Its Channel A. Ive looked at the front and rear in great detail and cant find a solution to solving this frustrating problem.

 

Ive enclosed photos to try and give a bit of info - If you have any questions that may help me get to the bottom of this I will be grateful.

 

One thing I noticed when I turned off the CD player mixer before the AMP (I know you shouldnt do that and I usually do it the otherway round ) I heard the crackle that one hears through the speaker on switching the player ...through both sets of speakers - but that's all i get out of the problem side.

 

cheers

 

 

 

http://img2.putfile.com/thumb/12/34422513427.jpg

 

JB system Rhythm 11010 mixer with graphic equaliser and twin cd players in flight case

 

http://img2.putfile.com/thumb/12/34422351398.jpg

 

Front view of AX400/AX700 amps & SoundLab Professional SPCX23 inbetween

 

http://img2.putfile.com/thumb/12/34422351338.jpg

 

Rear of JB Systems DJ5000

 

http://img2.putfile.com/thumb/12/34422351419.jpg

 

Rear of JB Systems AX400 amp

 

http://img2.putfile.com/thumb/12/34422351447.jpg

 

Rear of 2 way stereo @ 3 or 4 way - soundLab professional SPCX23

 

http://img2.putfile.com/thumb/12/34422351471.jpg

 

Rear of JB Systems AX700 amp

Edited December 12, 2007 by treen74

[eazy 0]

just gonna state the obvious ones just incase

 

have you checked the master balance on your mixer ???

 

tried new leads

 

tried a different output from the mixer

 

you get the idea basically checked all the simple stuff just incase.

its surprising how ofthen its something silly like a button being pressed or a knob turned in the wrong place or just a good old dodgy lead but just thought id ask the obvious first before the real tech heads get stuck into it

[Gary 0]

One of the "rear" photos showed the back of the mixer - Whilst there are several Red (right) and White (left) audio plugs in several of the sockets on the mixer, I noticed that there was one lead where only a single RED lead was plugged in. The focus/detail on the photo isnt quite strong enough to see what the label by the socket is - if thats an input, you'd only get one channel (either left only, or right only) when playing from that source.

 

Try some things...

 

You've got several pieces of equipment there, with equalisers, several amps etc. etc... try things like:

 

*) Plug a stereo music source (like a CD player) into the mixer

 

*) Plug a set of working headphones into the mixer.

 

*) Play the CD player and listen to it on the headphones on the mixer - do you hear music in both ears? If so...

 

*) Try just plugging the outputs from the mixer straight into the inputs of one amp and running one speaker (out of Channel "A" on the amp.

 

*) Assuming that goes well, switch it all off, and plug the speaker into the other output channel (B) of the amp instead - see if that works.

 

*) Plug speakers into both output channels on that amp -see if that works...on both speakers.

 

If that goes well, repeat the process/steps above but with the other amp being used instead etc....

 

Gradually build everything back up, eg: the other CD deck, the other amplifier, the equaliser etc, etc...

 

If anything doesnt work on on side eg: (works on "A" (left) but not "B" (Right) ) then try swapping leads between left and right etc...

 

 

let us all know how this gets on.

 

[Dream Catchers 0]

The picture Gary refers to is this one.

From what I can see it looks like an input for 'tape' that has a single wire connecting it to chassis ground.

Should that be plugged in?

 

Jim

Edited December 12, 2007 by JimBoylan

[treen74 0]

thanks for the replies so far guys. I finish work for a few days so can have a look at the equipment again tomorrow.

 

I do hope its something simple and nothing potentially expensive.

 

On a seperate note - do any of you get your amp etc serviced regularly ? I'd like to get my stuff given the once over by someone but cant find much in auckland that isnt run by a big company with big overheads.

 

I just dont want to envisage a situation where goes on me mid-gig. I'm not really into having 2 of everything either as it just wouldnt be cost effective at all.

[Andy Westcott 0]

Quote:

"I'm not really into having 2 of everything either as it just wouldnt be cost effective"

 

Until you have to abandon a gig half way through due to an equipment failure...

 

As for servicing amps, there is nothing to service, so don't pay out good money to a skallywag who tells you otherwise. One thing you can and should do from time to time is remove the finger guard from the fan(s) and clear out the accumulated dust from the fan blades and the heat sinks, as if you let this build up it will effect the cooling and in extreme cases could lead to overheating and eventual failure. This can be safely done using a half-inch paint brush - you don't have to remove every trace of dust, just the great big clumps of it that threaten to block the airways.

 

I personally like to spray a little contact cleaner onto the signal plugs and sockets occasionally, just to inhibit the build up of corrosion and to ensure a good clean connection. Probably not necessary, but it makes me feel good! smile icon

[Dream Catchers 0]

As for servicing amps, there is nothing to service,

That is not true.

The pots go noisy (pots = potentiometers = volume controls) also with age dry joints develop, also the sockets get loose.

 

Jim

 

[norty303 0]

The pots go noisy (pots = potentiometers = volume controls) also with age dry joints develop, also the sockets get loose.

 

Funny, I've got some aging amps that suffer from none of those problems despite lack of regular maintenance. Perhaps this is where buying better quality kit in the first place pays dividends in the future?

[Andy Westcott 0]

I would argue that a noisy 'pot' is more a case of the need for repair, rather than a subject for servicing.

 

My amps don't have pots - they are true slaves with no gain controls therefore the issue of worn pot tracks doesn't arise. Anyhow, how often do you alter the gain on an amp? I'd have thought that once you set it to match the mixer, that's it - it gets left alone, therefore a worn pot on an amp ought to be a pretty rare thing. smile icon

 

Also this dry joint business: (Sorry Jim! Not picking, just offering it up for discussion)

I'm not aware of a correctly soldered joint ever being able to 'go dry'. If the joint is correctly prepared, aligned, fluxed and wetted, it'll produce a stable solder joint.

A joint can fracture due to vibration or thermal stress, yes, but not otherwise become faulty. This would have to be a fault present from new, which raises again the notion of buying quality gear. And again, this would be a repair situation, not a service-curable issue.

Edited December 16, 2007 by Andy Westcott

[kenny wisdom 0]

By sheer coincidence I have had the same problem in the last fortnight with one channel having no output from a "cold start".

 

I checked all the wiring and satisfied that was in order I was quite perplexed - no knobs or buttons were in the wrong place. Then, just by playing around with the gain control to the offending channel on the mixer I heard some output struggling to get through. I turned the gain again, and the sound came through properly and stayed with me all night.

 

Back home, I tried again from a cold start and had the same thing, which the "gain" again sorted. This of course might be indicative of an impending equipment failure, but it serves to highlight one problem that can occur with leaving knobs in one position for long periods of time - occasionly a little dirt can accumulate on them and they develop "dead spots". I think it is worthwhile twisting all the knobs on a mixer regularly especially if you have a tendency to leave them alone most of the time.

 

 

[treen74 0]

:bouncy: Problem solved...........or identified for now.

 

It was the blue leads that comes from the mixer (DJ5000)into the Rear of the soundLab professional SPCX23 (both pictured above) - to be specific , it was the red coloured connection into the soundlab. I'm gonna need to get the connection soldered back on.......

 

I managed to find a set of leads (that dont look at thick as the blueys) in my box full of ....leads that do the job for now.

 

May look on Trademe (NZ's version of ebay) for a soldering iron - we''ll see..................

 

So I'm just about up and running - as suggested elsewhere I may have a look at the fans at the back of the amps and de-dust em

 

 

Thanks for your help guys :thanks: