Problem with DIY builds/switch-mode power supply

[jomaco]

Hi

 

I'm new to these forums but have searched around a bit without finding an answer so i'm wondering if you can help me on a few things.

 

I built a green ringer and a rangemaster (npn) based on diagrams from general guitar gadgets and fuzz central. They work fine with a battery however when I connect them to a 9v DC power supply they produce an unacceptable loud squeal in addition to the modified sound from the guitar. I'm pretty sure they are wired up correctly so i'm not sure what's going wrong. I have been using this power supply http://benfleet.abcmusic.co.uk/product.php/32864/52/. I thought that perhaps this is the problem?

 

Has anyone built either of these pedals? Is there a pedal supply that you know works with these devices?

 

Although I would like a voodoo labs supply and it would likely solve my problems they are quite expensive considering I only want to power a few pedals. I decided if i was to purchase anything less than the PP2 (i.e. a pedal supply with isolated outputs) I thought I might aswell just buy a 9v adapter.

 

Can anyone tell me if this 9v switched-mode power supply will work in a similar fashion to a 1spot/godlyke power-all? (I'd rather buy from a local stored than to buy onnline in case it does not work)

 

http://www.maplin.co.uk/Module.aspx?ModuleNo=48484&OrderCode=L46BL

 

Thanks for your help

 

Jon

[WRGKMC]

Chanceds are the noise is coming from the power supply either because the voltage/current is wrong or too high or it has insufficiant filtering. Try a zero hum adaptor like a Boss or Dan Electro. These wall warts have additional filtering and are very good for pedals that lack any additional filtering.

 

You can alos try using a 9v zenar diode on the pedal power input that will prevent damage from any AC ripple, limit the pedals input to 9v and prevent reverse polarity accidents. You could also add some chokes and caps to smooth the power input, but I think the zero hum adaptor should work. i knoe the Rangemaster was never designed for a power supply so getting an adaptor that mimicks a smooth battery input is very important.

[AMZ-FX]

Chanceds are the noise is coming from the power supply either because the voltage/current is wrong or too high or it has insufficiant filtering.

 

It's not the power supply, it is the pedal that has inadequate filtering Many builders will clone vintage pedals that were meant to run on battery power only, but they add a power jack and no extra voltage filter capacitors. The result is that there is noise or hum, which is as much due to the pedal design as to the power supply used.

 

Preventing hum: http://www.muzique.com/lab/hum.htm

 

regards, Jack