Double Bass Power bank for PJB Double Four

[Barry Cohen]

Hi. I have PJB Double Four amp for small “acoustic” D/Bass gigs. (It’s the earlier Double Four with an external mains power supply and a small DC plug going into the top of the amp.)
I’d like to use an external power bank to play outdoors. I understand it needs to provide 19V. Does anyone have any experience of these? (E.g. with this Krisdonia -
https://www.amazon.co.uk/Krisdonia-25000mAh-Portable-Charger-Projector/dp/B078XPYH4R )
Thanks,
Barry

 

[kkenda11]

I have not used that that power bank, but I have run my PJB double 4 off of a generic USB-c battery pack using the PD Buddy. I bought the PD Buddy, wired up a 9v power connector, connected it to my computer once to set the proper current and voltage needed by the Double 4 and voila, it worked.

PD Buddy Sink by Clara Hobbs on Tindie



So, I can attest that the double 4 runs fine off of a battery pack that is providing the correct voltage and current.

 

[pit lenz]

The Double Four works very well with a power bank!

I am using the Power oak K2 constantly attatched to my double four.
It delivers 19.5 V plus usb power and holds 50000 mAh. On top of the D4 there’s a Line6 wireless reciever. It’s been powered through a small stepdown circuit that turns 19V into 9V. Being able to play wirelessly, I just drop the amp just somewhere and don‘t think of it anymore.
When I first took it to a festival I was surprised that it easily held more than three days of jamming (a lot). Now, when I go to a gig, I don‘t even bother to take along the original psu. Very happy with it.
Laptop PowerBank K2 185Wh / 50000mAh - PowerOak B.V.

 

[bassically_eli]

I'm curious what people are using in 2025.

 

[WRM]

I have the Double 4 Plus, use this for power via USB port, and it works fine (not sure if it works on non-Plus).

Amazon.com