Fault on a Soundcraft Spirit Folio Mixing Desk

[GiggingAddict]

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 . 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 ) 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.

[Mike Stranks]

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...

[The Korff]

It might be worth checking the PSU voltages, if you've got a multimeter handy?

[Hugh Robjohns]

... 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.

[Mike Stranks]

Sorry! Should have been more specific in my previous post... I'm talking about the power supply connector and companion desk socket.

[Tomás Mulcahy]

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!

[GiggingAddict]

Hi all, thanks so much for your input, it's really appreciated. 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.

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.

[grab]

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.

[ChristopherM]

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?

[Martin Walker]

Hi ChristopherM, and welcome to the SOS Forums!

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).

Martin

[MartinTremor]

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 )

[ef37a]

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!

Dave.

[Mike Stranks]

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?

[ef37a]

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?

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?

Dave.

[Hugh Robjohns]

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....

H

[FabN]

Hello,
Had the same kind of issue with mine. It was one of the two symetrical voltage that failed.
Fixed by changing the voltage transformer.
My desk is 20 years old, appart from changing the input voltage transformer and potentiometers, is working like a charm, so far!

-FabN- from France

[swrbassamp]

Hi! I have the same mixer. I wanted to connect it to the computer via interface, to use it for some home recordings. When I connected it I couldn't see if there's any signal sent. I am not currently using any monitoring, so I cannot hear if there is anything sent, but when I turn the mic channel on I can see no lights showing signal flow, except when I press the pfl button, then it seems to get the signal and shows dynamic range and reacts to Gain. The Phantom power is on, all the connections seem to be right, cables as well, so I have no idea why there's no signal going through, unless the pfl button is pressed...

[ef37a]

Hi! I have the same mixer. I wanted to connect it to the computer via interface, to use it for some home recordings. When I connected it I couldn't see if there's any signal sent. I am not currently using any monitoring, so I cannot hear if there is anything sent, but when I turn the mic channel on I can see no lights showing signal flow, except when I press the pfl button, then it seems to get the signal and shows dynamic range and reacts to Gain. The Phantom power is on, all the connections seem to be right, cables as well, so I have no idea why there's no signal going through, unless the pfl button is pressed...

What is the make and model of the interface?
Which DAW are you using?
How exactly is the mixer connected to the interface?
Surely you at least have headphones?

Dave.

[shufflebeat]

As Dave says, a few more questions before answers but also, there's (sometimes, depending on model) a little purple "channel on" button at the top of the fader which is often the cause of such issues.

[Sam Spoons]

I've had a couple of Soundcraft desks over the years and, as Mr Beat says, they both had an 'on' button instead of a 'mute' button. I found this pretty confusing at times. It would have been much easier if they had stuck with convention and had 'mute' buttons

[OTE2020]

''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 ) 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.''

Lets be honest that bloody amazing ! There is a company called top hat electronics that have fixed some old kit of mine before at a very fair price & turned around without a couple of weeks, might help ( https://www.facebook.com/tophatelectronics if allowed to post - i have NO connection to this company for the record, just used them & had a super service from them)

Keep it alive

[shufflebeat]

That post was from the original (pre-resurrected) part of the thread but, to be fair, it was pretty amazing then.

[James Perrett]

Well I'm still using a 1981 vintage MM mixing desk for the occasional gig and the main studio desk was made in 1991 (as well has having a couple of others from the late 80's) so many mixing desks have a habit of lasting quite a while.

[shufflebeat]

Well I'm still using a 1981 vintage MM mixing desk for the occasional gig...

I have a vague memory of something Seck-like with MM on it, is that the one you mean or am I over-remembering?

I actually have one of the the Spirit SX desks stashed away in a hermetically sealed SKB case waiting for the time when it becomes vintage.

[fruit67]

Hi This is an oldish thead but I will give it a go. I have a Spirit Folio light, which has started to make noises, very similar to the ones described in this post. I tested the power supply, 18v on both sides. I hard wired it into the mixer to rule out any connector issues. When I press the phantom 48v button, its a sure way of generating the electrical noises, when i press it off, the noises continue, quiter and then after a few minutes they dissapear, but then will return with the irregularity of fire embers crackling. My question is what next? I can use a multi meter, couild someone point me what to follow, capacitors, and where would they be (any bad ones) Thanks for any help. (Been reading SOS since 92)