Birdcord: New Packaging and Technical Upgrade

Almost one year ago the Birdcord USB→9V Converter Cable has been released and as you can imagine I learned a lot of things and got a lot of feedback from you since then. I now integrated these lessons into the Birdcord to offer you an even better product.

new packaging birdcord pouch velvet bag drawstring output current usb 5v dc to 9v converter cable 5v center negative boss style effects pedals tip negative

New Packaging: It turned out that the acryl box is very unpracticable because it’s hard to put the cable back in (too small). I now replaced it with a beautiful drawstring pouch with the Birdcord logo on it.

Cable Length: Due to popular demand I changed the cable length from 50cm (19.7″) to 55cm (21.7″).

Soft Start: Powering bigger devices like the Boss RC505 or RC300 Loopstations or the Digitech Trio+ from USB power banks has been a problem before because these devices need a very high initial current/startup current. Even though the Birdcord could handle this current the power banks would shut down. Not anymore! I now integrated a soft start circuit into the Birdcord that allows starting up these devices without overloading the power bank. It works with any USB power bank with an output current of 2A or higher (small devices still work from any USB port of course).

More Output Current: The new revision of the Birdcord is capable of a maximum output current of 1000mA@9V. Having said that I still recommend not drawing more than 700mA for permanent use to have some margin left for short current peaks and to ensure a long life of the Birdcord and your USB power bank.

Thank you all for your support 🙂

P.S. I didn’t update the product pictures in the webshop yet because I’m going to release new voltage versions of the Birdcord very soon and will combine the photoshoot for all the different versions.

Great Reception Of The Birdcord | Product Of The Year

It has been about 7 months now since the release of the Birdcord USB to 9V Converter Cable and many musicians around the world already got one. Most use it to power their pedalboard, but there are also some who use it for powering synthesizers, drum machines, portable amplifiers and more. The feedback that I get is extremely positive. More than half of the sales come from recommendations. Thanks to everybody who bought a Birdcord, to everybody who provides me with feedback and product wishes and of course thanks to everybody who spreads the word online and offline, you are amazing!

Here’s an extract of the online reception of the Birdcord:


New Opto Tremolo In Development

After countless modifications and testing more than a dozen of different resistive optoisolators I am finally at a point, where my new Vactrol-based opto tremolo circuit sounds just awesome. I already sent a first prototype to Styrian guitar player “Sir” Oliver Mally, who confirmed my assessment: this is something big. I’m really looking forward to bringing this little sound monster to market in the next weeks!

scope tremolo prototype waveform rigol ds1054 stompbox amp style vactrol super reverb fender songbirdfx songbird fx

tremolo circuit developement songbird fx songbirdfx stompbox trem amp style opto optical waveform signal sound

Keep on  rocking!

How To Measure The Output Impedance Of Your Guitar

What Is The Output Impedance And Why Do I Even Care About It?

The output impedance or source impedance Ri of a perfect signal source is 0Ω. When talking about DC voltage sources it is also called internal resistance (That’s why I call it Reven though a guitar pickup is an AC signal source). A (passive) guitar pickup is by no means a perfect signal source (Ri > 0). This means that the output voltage will drop when connected to a load (effects pedals, amplifier). This effect will be more significant the higher the output impedance of your guitar pickup and the lower the input impedance of your amplifier/effects pedal is (voltage divider between Ri and RL).

guitar output impedance thevenin internal resistance effects pedal buffer voltage divider
voltage divider between output impedance Ri of the guitar and input impedance RL of the load

Recently I simulated the circuit of a Fuzz Face with LTspiceIV and realized that the output impedance of the guitar affects the final output waveform of the effects pedal.


Fuzz Face Schematic:

Fuzz Face Simulation Sound LTspice circuit impedance


Output Waveform Of A Fuzz Face With Perfect Signal Source (Ri=0Ω) At Input:

Fuzz Face Simulation with Buffer Pedal perfect signal source

Output Waveform Of A Fuzz Face With Realistic Signal Source (Ri=10kΩ) At Input:

Fuzz Face Simulation LTspice Output Impedance Guitar

You have to find out for yourself if you like the sound of those interactions or not. If you don’t like it you should reconsider the order in which your guitar effects are arranged in your signal chain. Buffer and booster/preamp pedals have a high input and a low output impedance. They can be used to preserve the original waveform coming from your guitar pickups when used as the first pedal in your signal chain. Active guitar pickups are even better than buffer pedals because the guitar cable is a (capacitive) load too.


How To Measure The Output Impedance Of Your Guitar Pickup?

For measuring the source impedance of your guitar you will need an oscilloscope. If you don’t have one you can use my results because it won’t differ that much. By the way the exact model name of my guitar pickup is a Seymour Duncan SH-4 JB in bridge position.

  1. Measure The Peak-Peak Voltage With Open Output:
    Turn your guitar up to full volume to make sure that the pots don’t influence your measurement. Then strum a note (I strummed the thicker E string).
    guitar source impedance measurement calculation output impedance

    peak peak voltage vpp guitar output e string signal waveform without load

  2. Measure The Peak-Peak Voltage With A Load (RL=1k):
    Strum the same note with the same intensity as before to get the best results.
    guitar internal resistor calculation measurement impedanceoutput waveform of a guitar maximum typical output with load measurement

  3. Calculate The Output Impedance Of Your Guitar Pickup:
    Finally we can take the voltage divider formulas from above and substitute the variables with our measured values.
    calculation guitar output impedance voltage divider formula
    Result: The output impedance of my guitar is about 10kΩ.

Note: The impedance changes with frequency. This result is only true for the lower E-string, however we can assume that it won’t change dramatically. To get a more detailed result you can repeat this procedure at different frequencies (different notes).


USB Rechargeable Guitar Effects

Are you tired of low 9V batteries in your pedals? This is now over! My company Songbird FX invented the world’s first USB rechargeable Overdrive pedal, the Bluebird Drive. Below you find a video of the Germanium version, produced by the great Mike Hermans.

Interested? Click here for more information!


Keep On Rocking!