I just got my Syntakt and wanted to try out with my Ripcord USB to 12V DC power cable Anker Powerbank). It worked always well with my Digitakt and Digitone.
After some minutes the Syntakt is turning off all the time.
with ST rated at 2A, the old ripcords are forced to work over specs (I think is rated 0.750 A). You should get a USB-PD battery and a PD 12V ripcord which works even at 12V 3A IIRC
I used a ripcord Anker powerbank absolutely fine with a DT/DN together, but it couldn’t handle an OT MK2.
I think even if the powerbank has a high current output, you don’t get a lot from the ripcord (you love current when the voltage is upped).
As others have said, the DT/DN only need 1A, whereas the OT/ST need 2A.
I’ve used only Birdcords, I can recommend them, tested them with DT and DN and working fine.
For ST, you would need smething lik this and a USB-PD compatible battery Birdcord PD→12V (USB PD Voltage Converter) | Songbird FX
I think Ripcord doesn’t offer a compatible adapter yet, of PD type (12V, 2A)
I had issues with a ripcord on my Maschine+ Because it was under powering it, it was misbehaving. I got a bulky Omnicharge battery with a DC cable and you can set the Volts & Amps on it so Maschine+ runs smoothly now. But it’s big and heavy.
But I can most definitely power Syntakt too with it.
BTW, PD batteries and a 12V PD Adapter should be able to power any Elektron machine without issues, including the Analogs that didn’t work with the old USB batteries. PD seems like a good invention.
The bottom line is that the current consumption peak at about 1.15A and stays just around 1A on average so anything that is rated just 1A will likely not work or it will be near it’s over-current cutoff point.