18V DC power...for guitar pedal...

[jkhuri44]

gday dudez...

just wondering if anyone knows where i can find an 18V DC (negative polarity) power pack for one of my Fulltone guitar pedals...i would like it to be regulated as well...

i bought one from an electronics store..in the city somewhere, it sounded good to start with then it starting humming....so...im guessing the voltage is not exactly 18V...or some other reason, but does anyone know where i can get power packs that actually match the specs on paper??

Cheers...

[Howard Jones]

Hi Jamil,

Can you explain more fully which bit is humming?

The very best solution in these cases is to assemble a custom power supply designed for the job, but I realise that this may not be an attracive solution for you.

Jaycar sell a regulated 18VDC/800mA plugpack - part # MP-3034. This is one of these wretched multi-voltage, multi-pronged things, so there are things to watch out for:

[1] Once the voltage switch is set to 18V, I would put a blob of silicone in there so that it never, ever gets knocked off position. Jaycar describe the switch as recessed so that it can't be knocked but I wouldn't trust that unless it looks very secure to you.
[2] Once you sort out the correct adaptor and polarity, you should heatshrink over the barrel so that no d*ckhead mate can borrow it and just "try the plug the other way round". I'm harsh on this because I've seen it happen. And putting positive volts in where the negative volts belong usually isn't pretty. If you can't heatshrink it yourself, bring it in here and I'll do it for you.

Jaycar also sell a dedicated 19V/3.16A laptop plugpack that may do at a pinch.

BTW, does this Fulltone pedal not come with the correct plugpack? Does the Fulltone importer sell something for this purpose?

And finally, the single biggest cause of trouble with plugpacks that we see is that the diameter of the connector that people use does not correctly match the diameter of the jack to which they are connecting. To most people, sticking a 2.1mm plug into a 2.5mm jack seems to work okay and the mismatch is barely noticeable. However, in use, especially in live work, the jack may not make a good connection (which made me wonder about yours humming). My experience of the typical Jaycar/Dick Smith shop assistant is that they can be very poorly informed on these matters and will be happy to sell you the nearest thing that seems to them to fit.

The other thing to check is the length of the barrel of the plug vs the depth of the jack into which you are plugging. It used to be that Jaycar/Dick Smith barrels were a bad mismatch for Sony portable devices, as Sony use a jack that is shallow compared to the plugs on a typical plugpack. I have noticed however that the Sony style plugs (distinctive yellow) are now available at Jaycar at least.

If you have a longer barrel than necessary you end up with some exposed metal that is not fully contained within the jack and this can touch other metalwork, short out etc.

Jeez, you'd think that nothing could be simpler than buying a plugpack...

Cheers,
Howard

[jkhuri44]

gday howard..

thanks for the extensive reply :)

the pedal in use with a regular 9V battery sounds good, however....Fulltone advertise that with the 18V powerpack, the pedal operates quieter, louder and with more dynamics....they sell 9V powerpacks with negative polarity, but thats just the same as using a battery and replacing it when it starts sounding shit.


i've already bought that multi plug, multi voltage powerpak from jaycar that you suggested...it sounded great, except it was givinga sharp BZZZZZZZZZZZZT sound in the background, which made it pretty unusable for recording in the studio..

this problem is pissing me off...the problem seems to be that the powerpacks , even thought they say they are putting out 18V...are not doing so, and the buzz is coming from that mismatch...

so yes, as you said, "you'd think this is a simple matter of going to a store"...but its not, and its pissing me off...whats worse is that Fulltone have bothered to make a high quality 9V powerpack with precise 9v output, but have not bothered to do the 18V version...

GRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRR!!!!

[Howard Jones]

Hi again Jamil,

If the plugpack is doing that, then it is not regulated (as claimed) or else the regulation is so poor as to be non-existent. Virtually all modern plugpacks appear to me to use some sort of switchmode power supply (the giveaway is that they are incredibly light) which don't tend to give good regulation in the face of highly-fluctuating loads i.e. music.

Of course, you can't rule out the possibility that the unit you purchased is actually faulty. I suppose it would be too much of a pain to drag the Fulltone etc into Jaycar and show them the problem?

Cheers,
Howard

[jkhuri44]

thats true,

any purchases are returnable, i bought it and returned it before, so i might just buy another one..

see if it works, if not...just return it again

thanks for that howard.

[Kris]

Hey Jamil,

Here's how I do it.

I have a T-Rex Fuel Tank power supply...you can use a Pedal Power or whatever... get yourself a 'Y' power cable from http://www.stompin-ground.com/products/sgpowerpp.htm and use TWO 9V outputs with the Y cable into the fulltone. I did this on a Fulldrive 2 and it was fine, no hum.

Kris.

[jkhuri44]

touche kris!

yeh, i read about these a while back, but i sorta forgot about em...

thanks for the reminder...hehe


: )

[jkhuri44]

just went to jaycar....and bought the 18v powerpack, and a 9v for another pedal...

which now leads me to ask...the pedal requiring 9v..needs 200mA current....the powerpack for it is rated as 1A current output, since its regulated, and "overload protected"...am i correct in assuming it should stop at 200mA??

(Kris...ill have to get that voodoolabs power supp in the future) :P

cheers,

JK.

[chris p]

JK

Yes. You always want the powerpack rating (1A in your case) to be higher than than the device current (200mA). The powerpack rating is the point at which it will go into meltdown, so you don't really want to be even close to that point.

The unit will still only draw 200mA current.

[jkhuri44]

thanks chris,

thats what i thought, just wanted to confirm :)

JK.