Making battery pack for pedal board

Hi,

I'm tired of the hum in my daisy chain setup with a 9V DC-adapter and I'm going to make a batterypack for my pedalboard. I will use 6 AA batteries in series in a batteryholder and a 2.1 mm DC plug. That will go into the daisy chain cable and further on to the pedals.

Anyone suspect that this will work without hum?

If this works out I will get myself a charger and rechargable AA:s too...

See if I can put up some pictures of the contraption if and when it works.

I think it will improve the "hum". I am worried it won't last all that long, which depends on how much current your pedals are pulling. I wonder if anybody has tried doing something similar with a small motorcycle battery or a UPS battery. Or imagine plugging into a big Sears DieHard on stage...that would be awesome!!! You'd have to just bring the DC voltage down to 9 volts.

You might consider this project:

http://www.geofex.com/article_folders/spyder/spyder.htm

I used one of these for years

www.guitarbits.com.au (http://www.guitarbits.com.au)

The first thing I would do is to add up the current draw of all the pedals that I had on my pedal board to see how much current I actually needed.Then I would have a picture of what is realistic.Seeing that you live in Sweden we could probably get hold of the same stuff.I think I was looking at a project like yours (AA-cells instead of power supply).At that time it simply wasn´t a good idea.You are welcome to drop me an e-mail anytime! Meanwhile,good Luck!

I'm wondering if the rechargeable 9.6v accumulators for RC cars would be any good in this scenario as an alternative?

I'm wondering if the rechargeable 9.6v accumulators for RC cars would be any good in this scenario as an alternative?

That sounds like a great idea! Those things probably really pack a charge. I'm guessing 9.6 V would work for most garden variety stompers, though that would need to be investigated. What's the voltage on a fresh out of the package (nominal) 9 volt battery? 9.2 or 9.3 volts? I can't remember.

That sounds like a great idea! Those things probably really pack a charge. I'm guessing 9.6 V would work for most garden variety stompers, though that would need to be investigated. What's the voltage on a fresh out of the package (nominal) 9 volt battery? 9.2 or 9.3 volts? I can't remember.

Several months ago I ran some life tests on different 9V batteries. I don't have the data in front of me, but I believe that some were around 10V, and some in the 9.2V range. A 9.6 battery would probably be fine.

I daisy-chained my pedals from the 6xAA battery pack yesterday and it worked fine so far. No hum. I will probably make a pack from 8xAA 1.2 V rechargeable NiMh batteries instead now.

There's five pedals on the board, btw: In front, Morley Power Wah, Korg Pitchblack, Danelectro Transparent OD

In the loop: Fame Sweet Tone Delay, Fame Sweet Tone EQ.

The wah is the only pedal w/o true bypass so it will be the first input where I can easily unplug the cord to avoid any current draw when not used.

I made a battery pack from 8xAA NiMh. The open terminal voltage was high, around 10.8 V , but I felt the force was strong with me yesterday so I plugged it in and the pedals seemed to like it just fine ;)

I made a new pedal board also I will show some pics in another thread

Edit:
http://www.tdpri.com/forum/burnt-fingers-diy-effects/311717-my-first-pedal-board-build.html

Pedaltrain is coming out with one. Seems like this is something that would have been commercially available for years.

The wah is the only pedal w/o true bypass so it will be the first input where I can easily unplug the cord to avoid any current draw when not used.

I am kind of a noob, so take that in mind when you read this question:

What does true bypass have to do with current draw? If you are making the assumption that true bypass means there is is no current being drawn even though there is a plug in the input jack of an effect, I think you're wrong.

If I am not mistaken, you will have to unplug each effect to avoid current draw, true bypass or not.

Since you are building your own power supply, your best bet would probably be to put an on/off switch on it.

Cool...that turned out really nice!

I am kind of a noob, so take that in mind when you read this question:

What does true bypass have to do with current draw? If you are making the assumption that true bypass means there is is no current being drawn even though there is a plug in the input jack of an effect, I think you're wrong.

If I am not mistaken, you will have to unplug each effect to avoid current draw, true bypass or not.

Since you are building your own power supply, your best bet would probably be to put an on/off switch on it.

Yes, you could be right about this. I just read it somewhere on the web and it made some kind of sense. As you said an on/off switch would be the best so I wired one up.

I can easily break the power to all of my pedals by removing just one plug.
Since I always have a BOSS TU-2 stage tuner first in the pedal chain which
have one 9 volt input and one 9 volt output jack in the front of the pedal
I put the plug from a 9 volt adapter or a battery pack into the first jack and
daisy chain the rest of the pedals from the tuners 9 volt output jack.
I can switch all pedals on and off by plugging and unplugging into
the tuners 9 volts input jack.I feel silly explaining such a simple thing but maybe
it was something like that you read explained even worse than my explanation.

http://us.sanyo.com/pedal-juice

http://us.sanyo.com/pedal-juice

That's really cool Roman. Their spec's don't specifically say, but looking at their examples it's about 2A/Hr = ~50Hr for one pedal or 4 Hr for one that takes ~1/2A. Should be good for most gigs - or buy two.

I once thought of putting several rechargeable 9V in parallel, but using several rechargeable AA's or other battery pack would get you there too.

I haven't tried that specific pack - but I'm very familiar with Sanyo Eneloops for my digital camera and other stuff - those are great, because they hold their charge very well; "regular" rechargeables lose their charge after a couple of weeks, even if you don't use them, the Eneloops will still deliver most of their power even a few months after charging...

The NiMh 1.2 V re-chargeable batteries I used for this project are rated at 2700 mAh each vs 250 mAh or so for a single 9V. Essentially this means that the batterypack is equivalent to 10 -11 9V normal batteries if I understand it correctly. For a five pedal board it would be like having a fresh battery in the pedal and one spare on tap for each pedal. An added benefit compared to regular batteries is of course that power hungry pedals will be able to use more of the total capacity as needed instead of being limited to its own single 9V cell.

It will certainly be interesting to see how long it lasts.

http://batteryuniversity.com/learn/article/serial_and_parallel_battery_configurations

The Sanyo Pedal Juice seems to be using LiIon technology and have 7350 mAh capacity roughly three times more than the 8xAA pack above.

The Sanyo Pedal Juice seems to be using LiIon technology and have 7350 mAh capacity roughly three times more than the 8xAA pack above.

Look at the specs again - that 7350mAH @ 3.7V
The unit puts out 9V, so there is some conversion there.

Their examples are pretty clear: "Current used about 1,000 mA: Approx. 2 hours" - That's 2000mAH (@ 9V)

Look at the specs again - that 7350mAH @ 3.7V
The unit puts out 9V, so there is some conversion there.

Their examples are pretty clear: "Current used about 1,000 mA: Approx. 2 hours" - That's 2000mAH (@ 9V)

Ok, so apparently they use one of those Li-ion cells and boost the DC up which reduces the mAh?

Ok, so apparently they use one of those Li-ion cells and boost the DC up which reduces the mAh?

That would be my guess, though 27W in and 19W out would indicate pretty poor efficiency (70%). For low voltage conversion 80% is a pretty common number, so 70% might be realistic. Using higher voltage cells or putting them in series like AA cells so you don't have to convert would reclaim some of that efficiency.

That would be my guess, though 27W in and 19W out would indicate pretty poor efficiency (70%). For low voltage conversion 80% is a pretty common number, so 70% might be realistic. Using higher voltage cells or putting them in series like AA cells so you don't have to convert would reclaim some of that efficiency.

At least it looks pretty though ;)