Tuesday 8 September 2020

USB to 9V 'Pedal' Cable

Histories of Electronic Music often  concentrate on hardware, in an 'insider' code: TR-808, DX7, MPC, D-50, RC-505, EIV, etc., or on bands/perfortmers/artists, again very 'insider' in nature: NIN, Erasure, Daft Punk, Deadmau5, Kraftwerk, Bassnectar, BT, Mili, Fluke, etc. Another possible method of categorisation might be recording technology, wire, tape, multi-track, portastudio, DAT, CD, mp3, SD card, etc. 

But there's one pivotal hardware technology that most people assign to the sidelines...

Power cables. Yep, those IEC mains leads, USB cables, the often-unloved wall-wart adapters and their captive leads, and... guitar pedal cables. At the risk of sounding like a movie trailer (remember going to the movies pre-lockdown?): 

In a world where data seems to be going wireless and enabled by lithium-ion batteries, distributing power to gear is still physical wires. 

Allegedly, the world nearly had wireless power via Nikolai Tesla's Wardenclyffe Tower experiments funded by J.P.Morgan (yes, that J.P.Morgan!), and magnetic induction on the grand scale may now be impossible because of the way we have developed electronics, but applications like mobile phone charging are viable, albeit over very short distances. Instead, we have mains electricity, or batteries. Batteries are increasingly not the throw-away zinc-carbon et al cells, but rechargeable lithium-ion et al, and the current knowledge of physics suggests that there aren't any huge leaps in energy density - so significantly smaller/lighter batteries with huge power storage will require huge advances in physics. Lithium-ion batteries are increasingly used in power-banks that can power more than just phones, and USB has become a pretty ubiquitous delivery mechanism.

However, guitar pedals are different...

Unfortunately, guitar pedals come from an era of 9V batteries made up of stacks of six 1.5 Volt cells: PP9s as they were called before the modern obsession with renaming battery sizes every few years started, which sounds a bit like the way that USB connectors and video connectors get changed every few years. But modern pedals often no longer have any provision for a removable 9V battery, instead a centre-negative 2.1mm barrel connector provides the DC power. - from the mains! But that DC power is 9V, not the 5 Volts that you get from USB...

Up until very recently, that was the end of the story. Pedals were 9V, (not USB!) and you used a wall-wart power supply to convert mains to 9V DC, with daisy-chained connectors for pedal boards (or better, but more expensive: isolated outputs). However, the last decade has seen a lot of advances in Power Converter chips, and they have got smaller and lighter... To the point where you can put them into connector plugs. So it is now possible to convert the 5 Volts that you get from a USB charger to 9V with what appears to be just a cable.

A Deluge of Ideas

It was the Synthstrom Deluge FAQs that reminded me about USB-to-9V cables. The Deluge groovebox is quite unusual because it can work of an internal lithium-ion battery (Yep, it really is very close to the 'Novation Circuit on steroids, or Circuit 2' that many people have wanted for some time...). I've got a small 'classic' Boss BCB-30 pedal board that is mains powered, plus several pedals (An OWL, a Poly Digit and various other 'boutique' pedals that might get put onto a board eventually (none of which have 9V batteries!). But power has always been the problem, and it goes well beyond the usual 'serious' pedal board design advice:

'Don't daisy-chain one adaptor: Use a power supply with multiple isolated outputs.'   

Synthstrom Audible suggest that one way to power the Deluge is to use a lithium-ion USB power-bank with a USB-to-9V cable to do the voltage conversion. So I ordered a couple of cables from Songbird FX...

BirdCords from Songbird FX

Here's what I got: two bags (everything is in bags these days!) with the ubiquitous stickers! What looks like a cable with a 2.1mm barrel connector on one end, and a USB plug on the other end, is the USB-to-9V converter cable. It can provide a peak of 1 Amp, which means that as long as your USB power-bank (or USB charger/mains adaptor) can provide enough current, then you can power quite demanding devices. I tried my Deluge, and with my usual 'LEDs almost at lowest brightness' setting, the current consumption was just over 300mA, and with full LED brightness, it went up to around 425mA. The Default 'full brightness' LEDs on the Deluge is very bright, by the way:

Deluge LED brightness illustrated
The Deluge can be very bright!

I powered the Deluge through the USB-to-9V cable for just under an hour in an ambient temperature of 25 degrees Centigrade, and the plug only got slightly warm, so it looks like there's no problem with providing about half an amp continuously. 

The cable is disarmingly small and light - the plug isn't a big heavy blob at all! I then tried it with a pedal, captured here in an 'action' shot:

As you can see, the 9V connector is plugged into a pedal, and I'm just about to power it via the USB connector. Stunning cinematography, eh?

I'm very pleased with my BirdCords. They are small, neat, do what they say, and are useful gadgets to have around for emergencies, as well as a perfect way to reduce the proliferation of different mains adaptors. 10/10 from me.


Okay, so the Deluge already has a battery inside, but there's lots of gear that doesn't! And none of my boutique pedals have batteries inside! So having USB-to-9V cables means that I can remove my dependence on mains power, by using power banks, which is great for live performance - especially unreliable mains power.  Even if mains power is available, then having just USB adapters/chargers means that I have more interchangeability in case something goes wrong... Losing power mid-set isn't my favourite experience: the thumps and clicks in the audio are bad, but having a laptop still powered up when your synths, drum machine and effects are all rebooting to an unknown state is pure stress and embarrassment. 

So my aspirational mobile rig would have a high power (20,000 mAh or more) USB power bank to power USB-powered gear, with USB-to-9V cables powering my pedal board. But my 'ideal' mobile rig would be to have two power banks with auto-switching between them... I'm trying to find something that does this...


Songbird FX - BirdCords, including the USB-to-9V cable featured here.

https://synthstrom.com/product/deluge/ - The Synthstrom Audible Deluge web-page...

http://n.wikipedia.org/wiki/Lithium-ion_battery - Info about lithium-ion batteries...


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