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PSU for Elektron MachineDrum MK1

I'm so lucky to have met some lovely people over the years and got to know many customers on a personal level. One of them is Alex Simler. Alex is... well, kind of a bit geeky, eccentric, loves old gear and recently commissioned me to build a power supply for the Elektron MachineDrum Mk1.

Being a simple 6V ac supply, this wasn't a particularly challenging or even difficult project. Alex lent me his MachineDrum Mk1 as he was off to New Zealand for a couple of weeks and this would be an opportunity for me to knock something together. After a couple of days and in-between my regular stuff, I WhatsApped Alex a picture of the finished product.

Low voltage socket on my power supply for the MachineDrum Mk1
A detachable low-voltage cable, helps provide added reliability.

Yeah, okay, it's a bit more fancy than your average wall-wart but that's just me. While the power cable is integral, the low-voltage cable is detachable. Hey let's face it, these cables get mashed, right? Having a detachable cable means that when your cable does get müllered, you can just buy another one or even just have some spares. It's a standard 5.5mm x 2.5mm DC cable and available for a couple of quid, bucks, Euros or whatever from Amazon.

Cable Gland on Power Supply for Elektron MachineDrum Mk1
An extra tough cable gland ensures that the power side of the power supply, is very secure.

The MachineDrum Mk1 pulls about 1.6A from a 6V a.c. supply. This means that the current supplied from the mains into the primary of the transformer is about 42mA when used on a 230V supply. Here's how you work that out:

Supply  Voltage  =  230V
Secondary  Voltage  =  6V
Voltage  Ratio  =  6/230  =  0.026
Secondary  Current  =  1.6A
Primary  Current  =  (Voltage  Ratio  \times  Secondary  Current)A
Primary  Current  =  0.026  \times  1.6A  =  0.042A

So with a current consumption of 42mA from a 230V supply, a standard value 63mA slo-blo fuse should be fine. WRONG! You need to cater for transients on the mains supply and I would normally double this without compromising safety. Hence the internal fuse is rated as such.

Since power is the product of voltage and current, if the supply voltage is halved from 230V to 115V, you have to double the current to maintain the same power. Hence the fuse rating on a 115V supply, is 250mA (2 x 120mA). Hope that all makes sense.

Elektron MachineDrum MK! Power Supply Current Test
Despite its simplicity, the power supply was fully tested. As you can see, the MachineDrum Mk1 requires about 1600mA and pleased to report that my power supply only gets slightly warm. YAY!

This power supply for the Elektron MachineDrum Mk1 is offered with either

      • a 3-pin UK plug with the PSU configured to operate on 230V.
      • a 2-pin European plug with the PSU configured to operate on 230V.
      • a 2-pin US plug with the PSU configured to operate on 115V.
Common International Plugs
PSU-MDMK1 can be supplied with one of these three common power plugs.

Anyway, the main thing was that Alex returned from his New Zealand adventures and loved his new power supply!

Incidentally, this power supply for the Elektron MachineDrum Mk1 which I've christened 'PSU-MDMK1' (well I had to call it something), can also be used on the Elektron MonoMachine Mk1.

You can buy this power supply here...

And if you need something a little special, just contact me. 🙂

And finally...


UPDATE - 18th January 2023

I recently got a MachineDrum Mk1 in that had been damaged in the post. The display cover was cracked and the display itself was intermittently failing to come on. Read how I installed a replacement display here.

Elektron MachineDrum Mk1 with new replacement display