SFX-6 power external power supply modification

My beloved SFX-6 internal power supply has always hummed mechanically, it does not affect the audio output at all and as it has got older it has got worse, I have had it from new as I was a beta tester, so it is well outside of warranty anyway.

The humming has always bothered me, because when monitoring at low levels it becomes very distracting, so I looked into various ways to eliminate it, I tried mains filters but they did not work, I read up on transformers and found that this kind of hum is caused by the laminations of this kind of transformers core vibrating.

To cut a long story short I contacted Elektron and spoke with Olle, he told me that spares were no longer available direct from Elektron but that the transformer part is still available from the manufacturer, I also asked what the rating was and asked about the possibility of using a mk1 sfx60 psu, but again these are no longer in stock, he advised me that a compatible part was made by Mascot in Norway so after a few emails eventually managed to get an external psu with a UK plug from one of Mascots UK stockists, the cost was just over £35.

Anyway fitted it today and all working fine, I made a small plate and removed the IEC socket and internal PSU, I used the internal wiring and switch, and only had to drill 1 3mm hole to fit the plate.

Now my SFX-6 is no longer humming :smiley:

If anyone is interested I will post some pictures and further details.

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Oh yes, very much so!
MY SFX-6 has never had a detectable hum, but a high-pitched whine at about 10khz.
I’m actually not sure this is the PSU, but possibly the CPU noise.
Still, I wonder if a new transformer would help.

Oh, the noise-floor is pretty bad on my unit, too! I remember that they improved this aspect in the MK2s, but that’s a completely different machine.

Anyway, congrats!

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The 10khz whine could be coming from the backlight inverter, mine did that until I replaced the screen a few years back. I have still got to finish up, so I will take some pics and give part numbers at some point over the weekend.

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Very much appreciated.
That whine has been a common characteristic in many of my tracks, but sometimes it ruins everything.

Yeah, my backlight flickers from time to time, but the sound doesn’t cut out along with the flicker. Still, I’d like to fix that, too.

Thanks!

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It is a bit of a pain to fix the backlight, basically you need to replace the whole screen assembly sadly, the good news is that the newer screens look much better.

Main things to be careful with are removing the knobs without breaking the encoders, and removing the old screen - I highly recommend to use a heated solder sucker and take your time (allow at least an hour) fitting the new one is easy once you have the old one out and all the holes clear.

Hi - do you have the part number for the replacement Mascot sfx6 power supply? I’m going to attempt to fix my poorly board. If that doesn’t go to plan I’ll need an external.

Thanks

I looked at the invoice and I ordered a Mascot 8810 Transformer in 13A style case – output 6V 3.2A AC You will also need a Mascot 3630 2.1mm female plug, and a 2.1mm socket for the sfx6 chassis. Those are UK part numbers so depending where you are they might be different but it should be enough for them to cross reference. :thup:

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Excellent thanks

Hello,

I may need to do the same on my MnM someday, I had problems to boot and been told by the customer service to check the connectors on the boards and reseat them. So far it worked but I saw that the humming PSU is connected to motherboard only, not the keyboard, and there is the AC connector of the SFX60 which is unplugged… so I guessed I could do this mod, plug the SFX6 to a 6V AC adapter… Can you show some pictures of your mod ?
Thanks a lot :+1:

Sorry I no longer have it and I looked for the pictures but I don’t seem to have them anymore either. @petitprofesseur
It is very simple to do though, the external PSU connects to the spot where the internal one does, I removed the internal PSU and kept the connector which I connected to a socket that I added to the chassis.

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Ok thank you for your answer :ok_hand: