Alto mixing desk issues

Dixon2000

New member
Hi all
I'm a newcomer and slowly putting a studio together with resources available.

The mixing desk I have (Alto PM12 Dragonfly) has given up the ghost and I'm finding it difficult to get someone to repair it.
I'm told the switch mode power supply has gone and is irreparable.

Anyone know anything about these ?
 
It may be a blessing in disguise.

Instead of spending money on repairs, invest it instead on an audio interface.

If you are getting into recording, that would be a more worthwhile investment.
 
Who told you the PSU cannot be repaired? Not the makers I bet, more likely someone who knows jack S about them and doesn't want the job!

That said, SMPSUs often "cook" and the complete unit need to be replaced, hopefully for a better design! (personally I would build an outboard AnneLoggy 50Hz supply but I suppose that is beyond your capabilities?). There was an otherwise excellent Soundcraft mixer that had a notoriously feeble PSU in it.

As stated, for home recording an interface is the usual and best choice but if you have a real need of the mixer I am sure it CAN be fixed. Going to cost though!

Have you contacted Alto?

Dave.
 
Thanks for your comments Dave
Yes been in touch with Alto who tell me they don't make replacements for this model any more and my best bet would be to search the web for spares or repairs.Appreciate if you could send some details on the Anneloggy 50hz supply maybe I could put something together !
 
Thanks for your comments Dave
Yes been in touch with Alto who tell me they don't make replacements for this model any more and my best bet would be to search the web for spares or repairs.Appreciate if you could send some details on the Anneloggy 50hz supply maybe I could put something together !

There is an excellent schematic for a dual 17V* supply with regulated spook juice in Douglas Self's t'riffic book, Small Signal Amplifiers. If you cannot easily get hold of a copy PM and we will sort something out.

*In case you are wondering, not a typo! Dropping the supply to chips such as Nee's and TLs by 2x1V reduces headroom by a paltry dB or so but apparently boosts reliability to near zero failures!

Dave.
 
If you didn't already, it might be worth asking Alto if a service manual is available for that board, which should include schematics. I took a quick look at my most common places I find service manuals and didn't find any.
I've a feeling that replacing/fixing may not be too straight forward as that board also has digital effects which may run off a different set of voltages than the analog part of it.

Good point Mark. However I have tended to find that the B'stds that discontinue products very quickly do not keep spares are the same b'stds that take a Dog in Manger attitude to supplying service data! When Behringer (who else!) told me the BCA2000 was ceased production I said "ok then, sell me a couple of spare boards and a schematic if you are not making it any more" Would they bollox!

Did not know of a digital side! Not likely too big a problem. If the digital juice demands is fairly low a 7805 off the LT supply should suffice. If a bit heavier OP can investigate DC-DC converters that "uptransform" current. There is almost always a way!

Dave.
 
It also looks to be a powered mixer, 300 watts per channel at 4 ohms, that's just got to complicate the power supply? I wouldn't use that mixer in a studio/recording situation even if it was working fine.
 
Alto have been good enough to send me a service manual with schematics (must feel guilty) Yes checked all fuses. Anyone know any good spares or repair sites maybe I can pick up an old Mixing unit I can take parts from ?
 
Alto have been good enough to send me a service manual with schematics (must feel guilty) Yes checked all fuses. Anyone know any good spares or repair sites maybe I can pick up an old Mixing unit I can take parts from ?

I would be obliged if you could PM me and send a scan/photo of the power supply schematic at least. I would not post it here because if Alto were good enough to send you it it is a bit of a betrayal IMHO to make it public? Breach of copywrite anyway.

DO NOT! Search for second hand mixer parts! Especially for power supplies. Components need to be new and of the correct rating, most of them will be "safety critical" and the grade might well have changed during production. It make no difference to the operation of the mixer WHAT the components are (must be safe) so long as the correct volts and amps can be supplied.

I did not pick up that this is a powered mixer? If so the PSU will be MUCH more powerful, an analogue, 50/60Hz version might be impractical. Mains fuse rating?

Dave.
 
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