Power Supply Project

[Willybomb]

Ok, I had a try at making a dual AC + DC power supply using this transformer:

http://www.jaycar.com.au/productView.asp?ID=MM2002

and this schematic, minus the 12v and 5v sections:

http://www.instructables.com/id/Build-A-Power-Supply-For-Your-Guitar-Pedals/

This was hooked up to the 0-9v tabs on the transformer which gave me a pretty steadyish 9vdc.

I hooked up a lead to the 0-15v tabs on the transformer to directly power the Blackstar HT-Dual.


Separately, when I hooked up the 9vDC to the 5 pedals (Berry tuner, DS-1, Bad Horsey, Berry FX-600, Biyang Baby Reverb) without the Blackstar connected, they all lit up quite nicely.  I didn't worry about playing through them - lets see the LEDs work first!

When I hooked up the 15vAC to the Blackstar without the DC pedals attached, it lit up nicely too.

However, the issue that occured was that when I hooked everything up (stomps to 9vDC and Blackstar to 15vAC) at the same time, my stomp LEDs started flashing (low volts?) and then the rectifier diodes on the 9vdc Verostrip let out their magic smoke.

What have I done wrong here?  The blackstar takes about 800ma-1.1a, so have I run too much current through the diodes in hooking the DC circuit up to the shared 0v tab?

[Willybomb]

Ok, I'm guessing it was a voltage mismatch or something as it was the diodes with their arses on the -ve rail that smoked. 

Anyway, we tried it by hooking both the the dc circuit and the blackstar lead up to the 15v and 0v tabs and again, the pedals worked fine if the blackstar wasn't hooked up, and vice versa.  The LEDs on the pedals flash and all the LEDs on the Blackstar light up (and dont respond to switch presses) if everything is connected at the same time.  So, I'm thinking there's too much current draw going on and nothing is getting enough off the one pair of tabs.

End result and conclusion:  Probably just easier although much less elegant, to stick a smaller dedicated transformer for the 9v stuff in there as well.

[bangerang101]

Isn't the power consumption of the blackstar ht dual, 22vdc at 1.1amps? If so, it doesn't have the proper output voltage/current.

[Willybomb]

No, mine's an older one from before they went to a DC supply - 16vAC, 800ma.

Trust me, I pulled apart the power supply that came with it and the only thing in there was a transformer between the mains and pedal.

[bangerang101]

Oh, ok... that makes sense. I just looked it up on google, thats why I thought it was that (22vdc at 1.1a).

Sorry!

Maybe its just something weird w/ that xfmr?

Like you said...pedals maybe pulling to much current when there all on or something, and the xfmr can't handle it...IDK, good luck!

[aballen]

Hey guys, sorry for the cross-post but I built a power supply recently and it turned out really well.  I thought I would share it.

I'm using the weber "spider" transformer.  One AC primary, to 8 11v(200ma), and one 9v(2000ma) secondary.

My layout converts all the 11v, down to 9vDC, and the 9vAC goes straight to a jack. 

You could of course change the output by playing with the resistors on the LM317, and I believe with a large input cap, you could get 12v out.

All 9 outputs are super clean and super steady, no trimmer necessary... I can post more pictures here if you would like... and no, its no longer cased in a spongebob lunchbox

here is a link
http://www.diystompboxes.com/smfforum/index.php?topic=97482.60

[Willybomb]

I'm seeing lots of different values for the filter caps in these PSU schematics.  RG's spyder uses a 220uF, one on instructables uses 100uF in the schematic but he actually used 10000uf in his project (!), and the one linked to earlier in this threas uses 2200uF.

I've built the instructable one on vero as per the schematic, and it works fine, but I also have some 220 lying around.  How much of a difference is it going to make?

[garfo]

+1 Great

[micromegas]

I've found this during my investigations on a new power supply:

http://n-audio.net/sites/default/files/Powerbox%20MK2%20Schematic.pdf

no values though

finally I got a Cioks DC10 for my birthday so... end of the story. But I would be interested on building another one for a second pedalboard...