Warhead Univibe: 2 Questions

[kinski]

I'm going to place an order for this pedal soon. Really looking forward to it!

Two quick questions:

1. Instead of the wall wart power supply, could I use a Y-cable with a Voodoolab Pedal Power?
2. For this buid, is it important for any of the components to be matched? I've read that some univibes, phasers, flangers need matched transistors, or something like that.

Thanks!

Also, going to build that Electric Mistress when it comes out! Thanks Madbean!

[kinski]

Also, is there an alternative IC that I can use instead of the LM7815T?

Thanks!

[madbean]

Using the y-cable should work okay. I've never tried matching transistors for a univibe, and honestly I don't recall seeing any mention of it before. I don't think it is very necessary. The main thing is choosing a transistor which has sufficient gain like the 2n508* or BC549, etc.

As far as other regulators: you don't have to use one necessarily. You can run the univibe at 18v, and since you are using a PP you already know the supply itself is well regulated. But, if you do use the 15v regulator make sure it is capable of supplying 100mA at a minimum. That's all that's really required.

[kinski]

Awesome! So would a 78L15 work instead of the 7815T?

Smallbear says the 78L15 is "+15 Volt 100 ma. regulator TO-92"

Thanks so much!

[kinski]

Okay, so instead of the LM7815T, if I use the 78L15, which is 15v 1000ma...can I still run the pedal at 18v?

[kinski]

Any help?

[DuctTapeRiot]

I am also looking for an alternative to the 7815T listed in the Road Rage PDF as I can't seem to find this at either Mammoth or Small Bear.  Mammoth has LM78L15ACZ which is a +15 v regulator good to 100mA, however the form factor is quite different, it is the same shape as  2N508* transistor, as opposed to the screw down bigger one that is shown in the document.  I am worried that the smaller package will mean issues with heat??

[jkokura]

Nah, the smaller package is what the old Road rage board used, and it's what I use pretty much all the time.

jacob

[DuctTapeRiot]

Thanks Jacob, you're awesome, I have been trying to figure this out for sooooo long.  I guess I am just a bit paranoid/nervous as I am still a bit noobish when it comes to going "off the map" so to speak.  Gotta learn to just go for it.  I also noticed that Small Bear has a 78T15 that seems to be the same thing as well.

[kinski]

So, I built this thing, and used a 78L15. Nothing happens. The lamp does not even light up. Any ideas? I have no clue where to start with such a big circuit.

[jkokura]

The size doesn't matter, the method is still the same. I would start with the "rules for getting tech help" thread, then post a tech help thread that will focus on your pedal. Get 'er going and we'll give you as much help as we can.

Jacob

[madbean]

7815T, ACT, ACZ are all pretty much the same. They are preferred over the smaller TO-92 size regulators in this case because they have better voltage regulation and more current output (1A vs. 100mA).

Your problem isn't necessarily the regulator. You need to provide some voltages first though, otherwise there isn't much to go on.

[kinski]

Alright. Well, I'll pick this thing back up after this weekend, as I'm out of town for the next few days. I'll start a new tech help thread. Thank you guys! Happy Holidays to all of you!