Posted on Nov 30 2019 06:37 AM
Hi Downed_Aviator, That is a great looking build! Welcome to the red toolbox reverb club. I'm especially excited to see that you are using a 5v to 12v USB step up cable to power your unit. You are the first person I've seen use that technology here at SG101 since I posted about it when I built my pedal board. I don't think a 12v USB adapter was available when I built my board. It looks like it was first introduced early this year, so thanks for bringing it to my attention. I definitely plan to work it into my Surfy Bear build.
What type of power bank are you using and how long can you power your Surfy Bear reverb with the Songbird FX's Birdcord 5v USB to 12v DC adaptor cable?
I have rather a lot to say about the power bank.
I use 5 volt power banks that I bought from Wish.com, they seem reasonably priced. For gigging I would advise having some fully charged extras on hand.
These arrive without any manufacturers technical specifications or conformity statements and no markings on the product whatsoever. So I have no idea what battery technology is being used or how many charge/discharge cycles they are capable of. On one of them I managed to break one of the charging points by applying a little too much sideways force and it fell inside the casing. Fortunately there are two charging points provided so I can still use it.
The marketing claims that they can deliver 900000mAh. Pinocchio has nothing on these guys! It also says fast charging, which is true and not true, which I will explain when I discuss battery discharge rates.
The marketing also claims 3 amps maximum output. I cannot verify this but they do the job and I have successfully run the Surfy Bear and some daisy chained effects simultaneously without a problem. For the BirdCord DC convertor cables Songbird FX say that the rated output current of your portable USB battery should be 2.1A or higher. The Songbird FX web site provides some good detailed technical information. They also manufacture and sell rechargeable effects pedals ;)
These are larger than most power banks and have four 5v USB outlets, 2 charging points, 1 micro USB and one Apple Lightning socket, which provide some flexibility for charging. They also have an LED lamp.
One very useful feature is a large LED display that shows the percentage battery charge remaining. The display automatically sleeps to conserve power.
I use 3 of the outlets. One to the Surfy Bear via a 5v to 12v step-up cable, and two to a double USB socket mounted on the toolbox lid as auxiliary power outlets. A single USB socket is also mounted on the lid as a charging point for the power bank. Some Velcro keeps the power bank in place.
WARNING: I found an issue when running on battery and trying to charge the power bank at the same time. The Surfy Bear lets out a loud squeal like a stabbed pig! Don’t do that.
When powered by an external power supply, the Surfy Bear operates normally while the battery is being simultaneously charged from a separate phone charger/laptop USB outlet or whatever without any problem. I mostly run it this way to keep the power bank topped up while it is being used just to provide power to some additional pedals via USB 5v-9v step up cables connected to the aux power outlets. A bit of a clunky arrangement, but it works for me.
NOTE: The Surfy Bear DIY Kit comes with a type of DC-jack that uses a switch built into the socket that will automatically connect the battery when no external power supply is inserted. The Surfy Industries FAQ states that this only works with center-negative polarity.
I have used these connectors before to add external power options to battery only devices. My power adaptor is center positive, so despite what the FAQ says I just reversed the way I would wire it for center-negative, therefore I am switching the negative side of the power rather than the positive. Doing it this way I still got a small residual reading of less than 1 volt between the disconnected battery negative and the positive terminal (why?). As I have no fear and like to live dangerously I proceeded anyway. No smoke, sparks, or flames, and I am still alive... so far.
Coming next... Power bank discharge rate.
Last edited: Nov 30, 2019 07:54:04