Road Rage question

[Matt Gnarly]

I've read the pdf a couple times now and I'm still not entirely clear on this, can the Road Rage be used to power multiple effects?

[JakeFuzz]

I asked this same question a while back. You are really limited on how much current your charge pump is able to deliver. I think the general consensus was that for a few effects (1-3) a single road rage would be fine but for many more devices multiple charge pumps are recommended. It also depends on the effects you are trying to power (even a single charge pump wont power something like the Warhead vibe!)

[Matt Gnarly]

Thanks for the reply, I ordered two PCBs so maybe I can house them together and power 4-5 pedals at a time.

[JakeFuzz]

Just to be sure you're using separate outputs for each road rage right? I don't think you can put two in parallel to double the current output and just daisy chain from one network, at least I've never seen anyone try that.

If you look at the data sheet (MAX1044) they have a set of operational graphs that show some of the output characteristics as a function of increased load current. It looks like the efficiency and output voltage drop off quite a bit after 10ma which is pretty small. Check out this site which lists the current draw for a number of popular effects.

http://stinkfoot.se/power-list

You'll see that most overdrive effects consume 10ma or more. I run my Fulldrive and Timmy on max1044's and they seem to be just fine. 

[shawnee]

If you want to run a lot of pedals, you may want to switch to the LT1054. It can put out about 100ma. Bean told me that the TC1044 is good for about 20ma.

[Matt Gnarly]

If you want to run a lot of pedals, you may want to switch to the LT1054. It can put out about 100ma. Bean told me that the TC1044 is good for about 20ma.

Thanks for the heads up, I'm completely new to this stuff.  So would I just run a daisy chain off the output?

[shawnee]

Yeah you can do that but it kinda defeats the purpose of having isolated power for each pedal (to reduce noise and eliminate ground loops). The LT1054 is about $3 each and the TC1044 is about a dollar. Since the Road Rage is only $2, you could use separate boards with a TC1044 for not much more. You don't even have to build the whole Road Rage board depending on what you are using it for. I agree with Jakefuzz about putting the road rage in the pedal. For less than $4 woth of parts you would be able to power the pedal with any normal negative tip boss style 9V supply and not have to worry about interaction with other pedals causing a problem. That being said, you can probably power several pedals and never have a problem. You really can't hurt anything by trying. If you have a buffer somewhere in the pedal chain, it helps with noise as well. So what voltage are you needing and what effects are you trying to power? Another thing is the TC1044 can take 12v in and the MAX1044 is really only good for 9V. I have used a TC1044 with 12v in to get +/-12V out which is nice.

[jkokura]

One benefit to using the road rage for multiple pedals is that you can power things different ways. So for example, you could run one at ~18v, one at 12V using a regulator, one at 9V using the jumper, and another a -9V, all without interfering with one another or causing any hum or other issues.

You could also run multiple pedals at ~18V or at 15V, or 12V, or -9V, which is a big benefit. For example, you could run a rangemaster and a fuzzface in one enclosure using -9V from one Road Rage while supplying the box with one Boss standard power supply. Huge benefit right? You could run an OCD clone and a Zendrive clone using 18V on both, again powered with just one 9V boss standard plug. All easily done, all a great benefit.

As mentioned, you do have to think about power draw though. Using an LT1054 for multiple pedals is a good idea, just make sure you find a way to deal with the problem with pin 1 on the LT1054.

Jacob

[Matt Gnarly]

Thanks shawnee and jkokura, I'm a complete noob when it comes to this stuff so I'll be asking for help when I get the pcbs and all the parts, probably won't get a chance to get started on this till December.  So realistically how many pedals could I run off of two of these pcbs?  I'm kind of looking for a DIY Voodoo Lab Pedal Power alternative.
Thanks again for all the insights.

[shawnee]

Glad I can help. By the way, if Jacob and I contradict each other on anything, ignore me and go with Jacob's advice. I haven't been at this very long either.

The best thing to do would be to pull up the mouser electronics website and do a search for the IC chips that are in the pedal to see what kind of current draw you have. Typically, transistors/FETs don't draw much at all so a dirtbox may draw less than 10mA. Some of the typical dual opamp IC's can pull 10ma each but are not all the same. The NE5532 seems to need more current than some of the other types. As a general rule, the more chips, the more current it will take.

Don't forget what Jacob said about the LT1054. Pin 1 and 8 should NOT be connected when using that chip and it is on the Road rage pcb. Bean suggested using 2 sockets and pulling pin 1 from the socket between the chip and the socket that is soldered onto the pcb.