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Fault on a Soundcraft Spirit Folio Mixing Desk

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Fault on a Soundcraft Spirit Folio Mixing Desk

Postby GiggingAddict » Wed Dec 14, 2016 2:56 pm

Hi everyone.

I've been reading the forum for a bit now to help me with problems that I've had in the past, and also to build up my knowledge, but I've got a problem that I couldn't find a solution for so I thought I'd check to see if anyone could potentially be kind enough to help. :) I've got a mixing desk, a 20 channel Soundcraft Spirit Folio that has developed a recent problem. Yesterday it was fine, no problems at all, but today when I turned it on there was a loud 'feedback loop' style sound coming from it, even with nothing plugged into it . :thumbdown: Even with all of the gains and the faders turned down the loop is still there, with the LED's that indicate signal coming through the desk staying at a constant level of about 50%. The desk is old, bought brand new in 1993 so it has long outlived it's expected lifespan, and so I expect that the problem is that it has just hit the end of it's life, but I just wanted to check first as money is very tight for me at the moment, (typical musician :P ) and it would be great to not spend money on repairs that don't work, or on a new desk that I don't need.

Just for more background, it's used in a shared rehearsal studio between many bands so it gets used at least 30 hours a week, powering a PA system. So by my reckoning it's done about 25,000 hours in its life. I've tried the usual things, with compressed air and switch cleaner, but nothing has worked so far. The electrics in the building are all in tip-top condition too, as the studio owner has an electrician come in every 6 months to check them over, and we are given a plug tester that we are asked to use every week, and they check with us every week to make sure that we do use it, so I don't think that that is the problem.

Thanks again for any help that anyone can potentially provide. We are more than happy to return the favour if possible. :thumbup:
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Re: Fault on a Soundcraft Spirit Folio Mixing Desk

Postby Mike Stranks » Wed Dec 14, 2016 3:39 pm

Those Folio desks had a very idiosyncratic connector on the desk/connector. In my experience these have often been responsible for the sort of woes you're experiencing.

Don't know what your DIY skills are like, but a change of plug & socket might fix things.
'grab' of this parish has carried out such mods. He's not around here much these days, but he might respond to a PM...
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Re: Fault on a Soundcraft Spirit Folio Mixing Desk

Postby The Korff » Wed Dec 14, 2016 3:47 pm

It might be worth checking the PSU voltages, if you've got a multimeter handy?
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Re: Fault on a Soundcraft Spirit Folio Mixing Desk

Postby Hugh Robjohns » Wed Dec 14, 2016 3:58 pm

GiggingAddict wrote:... when I turned it on there was a loud 'feedback loop' style sound coming from it, even with nothing plugged into it .

A feedback loop can only exist if the output of some part of the circuitry is connected back to the input in some way, and with an overall gain of greater than unity. That doesn't seem very likely with nothing plugged in... so when you say "nothing plugged in" do you mean just the inputs, or the outputs too?

Check that anything plugged into the outputs is plugged into the correct places, and that all the routing and monitoring switches are in sensible places!

Even with all of the gains and the faders turned down the loop is still there, with the LED's that indicate signal coming through the desk staying at a constant level of about 50%.

If all the faders are down and the noise is still present, then it's likely that the noise is being generated in the main output or monitoring sections.

A failing power supply (or a missing mains earth somewhere) could put considerable amounts of hum onto the power rails and that might account for your problem -- but that would sound more like hums or buzzes rather than a 'howl'.

It might also be worthwhile checking and cleaning the master insert sockets.
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Re: Fault on a Soundcraft Spirit Folio Mixing Desk

Postby Mike Stranks » Wed Dec 14, 2016 9:10 pm

Sorry! Should have been more specific in my previous post... I'm talking about the power supply connector and companion desk socket.
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Re: Fault on a Soundcraft Spirit Folio Mixing Desk

Postby Tomás Mulcahy » Thu Dec 15, 2016 5:18 pm

Yes great desk, lovely eq and sounds like a didgeridoo when overdriven, really nice. Two faults as have been alluded to:
1. Replace PSU connector with anything else, even solder directly to board which is fine if the desk is installed and never moves.
2. The sockets are unreliable, as H says test the master inserts. Awkward to replace because you'd need to remove every knobcap and unscrew them all from the front panel. So hopefully a bit of exercising (plug in and out several times) will fix that!
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Re: Fault on a Soundcraft Spirit Folio Mixing Desk

Postby GiggingAddict » Mon Dec 19, 2016 8:24 pm

Hi all, thanks so much for your input, it's really appreciated. :clap: :thumbup: Apologies for the late response. To clarify, yes, the sound is present with absolutely nothing plugged into the desk, in either the outputs or the inputs, which is what threw me. It's strange, one minute it was working perfectly and sounding great, the next minute it had the loud sound in it. :cry:

I am quite limited with my knowledge with these things, but the guitarist in our band is a dab hand at electrics as he repairs electric guitars, (his job is building acoustic guitars and he has a sideline in repairing electric guitars), so I'm going to forward him the details now and leave it to him. I wanted to see if it was in my remit first, and it looks like it might be more complex than my capabilities will allow for. ;)

Again, thanks so much for the input, it's been a huge help. We're going to scour through the other threads on the forum over Christmas to see if there is anything that we can help other people with, to keep the good karma going. Hopefully there will be. :angel:
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Re: Fault on a Soundcraft Spirit Folio Mixing Desk

Postby grab » Fri Jan 06, 2017 6:29 pm

As Mike says, I modded the power connector on my Folio.

This isn't a fault I've seen with mine though. I've got several dodgy faders and an iffy panpot, which at some indeterminate time in the future I'll fix if I ever get out gigging again, but I never had it do howl-rounds spontaneously. I'd always had to cock up somehow to make it misbehave.

You say nothing is plugged into the outputs. This suggests you're listening on headphones. Do check whether the outputs are also misbehaving, because it may just be something on the PFL/AFL.

You say all channels are off and all gains down. Check you haven't got the "2-track return" switch on - I've done that, and been very confused why nothing is coming out! It may be those inputs have gone screwy and you haven't noticed until you've hit the button. Switch it back to "normal", and you may be OK. Also go round the whole desk and check your PFL/AFL buttons, because my normal cockup for failing to hear things correctly on headphones was having an AFL button pressed on one of the auxes/submixes and not realising.

In the "stupid questions" department, have you absolutely definitely checked that all the gain pots are turned all the way left? I don't just mean eyeballing them - actually physically turn them. Knobs do come loose, and pots shafts do come disconnected from the bit they're turning.
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Re: Fault on a Soundcraft Spirit Folio Mixing Desk

Postby ChristopherM » Sun Nov 11, 2018 3:14 pm

Hmm ... I have just experienced what sounds like a very similar fault. Working normally one moment, feedback the next. It's not acoustic feedback (howlround). The character is very rapid "putt putt" or buzzing. Meters are maxed out. Unplugging everything (including phones) does not stop the phenomenon, judging by the meters (although obviously you can't hear it without phones or the main outs connected). None of the controls affects the feedback at all, except that moving the "monitor + phones" level control changes the sound a little. I know this is an ancient thread, but was the cause of OP's fault ever found?
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Re: Fault on a Soundcraft Spirit Folio Mixing Desk

Postby Martin Walker » Mon Nov 12, 2018 2:27 pm

Hi ChristopherM, and welcome to the SOS Forums! 8-)

I'e just had a look back, and the OP (GiggingAddict) doesn't seem to have posted in the last year or so.

However, judging from my quick read through the thread the symptoms do sound suspiciously like a power supply issue to m.

Either your Spirit Folio PSU has ceased to work (you may be able to check this with a multimeter into that dreaded multipin plug on its output), or one of your power rails has gone short circuit inside the mixer itself (possibly a tantalum capacitor fault, which would involve rather more investigation by someone with a circuit diagram who knows what they're doing).


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Re: Fault on a Soundcraft Spirit Folio Mixing Desk

Postby MartinTremor » Wed Feb 06, 2019 3:19 am

I had the same issue so in the end I hard wired it and cured the problem straight away but if you are moving it about and not having it Installed in a venue use different connections (XLR/powercon/IEC et )
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Re: Fault on a Soundcraft Spirit Folio Mixing Desk

Postby ef37a » Wed Feb 06, 2019 10:10 am

I don't usually think it is necessary in most cases but "re-capping" could be indicated? At least in the output circuits. You can get a batch of bad capacitors.

BTW. Gone off Soundcraft a bit. Bought son in France a Notebook 8fx last year and he wanted some oprerational guidance. My first task was to find a signal flow block diagram. None in the handbook so an email to Soundcraft. (well, one of those blasted forms with a robot checker!! Why are the *^%&Y photos SO dark? Took me about 5 tries to prove I was F&B!)

To be fair they did come back to me very quickly but only to say they don't do such diagrams any more. I replied that Behringer used to do them and in fact, for all their faults, their user manuals were SO good I used to use them to explain things on forums. Then they dropped signal diagrams so Soundcraft are now in "good" company!

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Re: Fault on a Soundcraft Spirit Folio Mixing Desk

Postby Mike Stranks » Wed Feb 06, 2019 11:18 am

World's moved on Dave...

There's a continually shrinking number of people who purchase such products and are:

a. interested in such a diagram
b. able to interpret what it's saying

Analogue mixers at that end of the market are increasingly just commodities, People buy it to do a job; they aren't remotely interested in how it does it.

And in a fiercely competitive market-place where profits are cut to the bone then omitting such diagrams saves a few pence.

Nostalgia's not what it was is it? :lol:
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Re: Fault on a Soundcraft Spirit Folio Mixing Desk

Postby ef37a » Wed Feb 06, 2019 11:31 am

Mike Stranks wrote:World's moved on Dave...

There's a continually shrinking number of people who purchase such products and are:

a. interested in such a diagram
b. able to interpret what it's saying

Analogue mixers at that end of the market are increasingly just commodities, People buy it to do a job; they aren't remotely interested in how it does it.

And in a fiercely competitive market-place where profits are cut to the bone then omitting such diagrams saves a few pence.

Nostalgia's not what it was is it? :lol:

Sorry Mike but I can't agree.
First off, you can't really start to design such a device without a basic idea of where the signals go! After that there will be several drafts of PCB designs and several people will have a very clear idea of how the thing works. In short, the dignal flow diagram will already exist and it cost nothing to include it in the user manual .pdf.

The idea that "people are not interested in how a mixer works" does not hold water judging by the amount of questions I answer on forums!
I will agree that some people just buy such a mixer, plug in a mic and feed it to a PA on stage and never need to know more but the growth in home recording is phenominal and mixer are bought for one purpose (or often just on a whim!) and then the user wants to do something different with it but has littlec lue how to go about it.
A signal flow diagram can help show them how or, in some cases show that the function they want is not possible.

In these lean times (I will not bore you with why!) surely companies should be giving consumers all the help they can to KEEP customers, not less?

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Re: Fault on a Soundcraft Spirit Folio Mixing Desk

Postby Hugh Robjohns » Wed Feb 06, 2019 1:16 pm

ef37a wrote:A signal flow diagram can help show them how or, in some cases show that the function they want is not possible. In these lean times (I will not bore you with why!) surely companies should be giving consumers all the help they can to KEEP customers, not less?

I agree Dave. Really silly to not include a basic block diagram. A picture paints a thousand words... and all that.

Having said that, I frequently find errors in mixing console block diagrams.... ;)

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