Making a 9 Volt Pedal Power Supply / Old Radio Shack

[plexi50]

I want to build a regulated heavy duty 9 volt power supply for all my pedals. Sick of batteries and expensive alternatives

I have an old Radio Shack 13 VDC 2.5 amp regulated power supply to work with. Do i change the voltage chip value to get 9 VDC out?

The transformer secondary is 4 VAC to rectifier

I tried just using a pot in between the transformer and board to control the voltage but that does not work under load

I found a schematic online to build one and then i thought of my old CB power supply that i found new in the box at Goodwill 3 months ago

What to do? Where to start? There are (2) chips on the Radio Shack board and to heatsink.

[sluckey]

Do you have a schematic for that PS? If so, it's probably as simple as changing two or three simple components. If no schematic, throw the pcb away and build this simple regulated PS. I'm using this and a wall-wart to power 8 Boss pedals plus a '70s Crybaby. I wouldn't hesitate to hang a few more low current pedals on it.

The regulator chip is a TO-3 style and needs a heatsink. Chassis works, but you gotta isolate the chip case from chassis with a mica washer and appropriate mounting hardware.

[plexi50]

Thanks Steve, I always appreciate your help.  I have looked high and low but no go on a schematic for this. Too bad it isnt under the cover like in the good old days

You say adjust without a load / Wont 4-5 pedals draw it down a bit? Im not thinking clearly. It is regulated im forgetting so the 9 volts will be solid

( you gotta isolate the chip case from chassis with a mica washer and appropriate mounting hardware) I will remeber that!




I have a dasiy chain of 8 BOSS plugs to hook to this / I bought a bad small PS off Ebay and it was pulsating as soon as pluged it in
 
I will tackle it tommorrow when im fresh. Speaking of Cry Babys i bought this one last night. I couldnt resist.

http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=320559697641&ssPageName=STRK:MEWNX:IT

[sluckey]

That's the same one I have. Bought mine new in '71. It's one of the few things I still have from those days.

[plexi50]

Ya know i have read a lot of bad things about the TDK 5103 i believe inductor.  If it was good enough for Hendrix then it's good enough for me. I love the tone they have stock. I dont understand why a lot of people diss them with the TDK.

The Micronta PS board is too simple. I think i have it figured out. I dont need a schematic to figure this one out. I will just remove it and use that board to build from the schematic you provided.  Early in the post i was spending too much time looking online for a schematic for the Micronta and not enough time looking at the board itself

I got silly last night after the PS i bought off Ebay was dead. So i made 7 videos for youtube. Nothing better to do. Im not into the video crap much but i went all out on this. Just a big joker making light of my newly purchased and usless pedal power supply

[Shrapnel]

I got silly last night after the PS i bought off Ebay was dead. So i made 7 videos for youtube. Nothing better to do. Im not into the video crap much but i went all out on this. Just a big joker making light of my newly purchased and usless pedal power supply

Too bad that all your videos appear to be limited to 16 seconds. May that 9v PS rust in peace.

[plexi50]

I dont have time or really get into making videos. Too busy.  But i found time to kill. Yeah thats what suks about my camera
Great old Sony Mavica FD83 but only 15 sec of video. 144MB Floppy camera. Services were held yesterday at my garbage can at 3:30 PM. Boo Hoo hoo-ooo

[SLW]

You could go with a 7809 regulator.  It has a wide input voltage range, is non adjustable and rated for 1A.  It makes for a few less componenets in the circuit.  You can power several pedals with one amp.  There are other regulators out there that would work well also.  Building a supply for pedals is pretty simple.  Transformer-rectifier-smoothing cap-regulator.

[plexi50]

I ordered (2) regulators. One  7809 and one LM123K. I will figure out which direction to go when they get here

Also Steve the TO chips on the chassis mounted heatsink are isolated and have the rubber piece under the chip to the heatsink and a nylon screw and nut

I ordered a few NOS AC128 Tungram PNP germanium diodes from the UK and some other NPN AC128 germaniums from Bulgaria. They are already tested and matched

Will see if i have been taken or not later. Got to take a chance sometimes

[sluckey]

One  7809 and one LM123K

The 7809 is good for 1 amp. The LM123K is good for 3 amps. More amps means more pedals from a single regulator.

the TO chips on the chassis mounted heatsink

I believe those chips are really transistors, TIP31 and 2N3055.

I ordered a few NOS AC128 Tungram PNP germanium diodes from the UK and some other NPN AC128 germaniums from Bulgaria

Surely those are not related to that 9V PS.

[plexi50]

One  7809 and one LM123K

The 7809 is good for 1 amp. The LM123K is good for 3 amps. More amps means more pedals from a single regulator.

3 amps is the way to go. I ordered the other one just to have one if i need it later for some thing else

I ordered a few NOS AC128 Tungram PNP germanium diodes from the UK and some other NPN AC128 germaniums from Bulgaria

Surely those are not related to that 9V PS.

No the germaniums are for other pedals i may want to build. I should have left that out of the issue at hand


To regulate the supply from 9-12 volts am i going to use a trimmer pot to accomplish this?

Ok i see. The 500 ohm is a trimmer pot right?

I found this site online. Full of DC PS Schematics: http://www.circuit-finder.com/categories/power-supply/dc-power-supply/page-1

[simonallaway]

The LM123K is good for 3 amps. More amps means more pedals from a single regulator.

I'm thinking of building this device. Is this the link below a good equivalent to the LM123K? Mouser has a ton of them and the differences seem to boil down to 'line regulation'.

http://www.mouser.com/ProductDetail/STMicroelectronics/LM350K/?qs=E0mHVHmM7ubGALVugtICYQ%3d%3d

Thanks,

Simon

[sluckey]

That LM350K is adjustable 1.2-37V at 3A. It should work fine for the LM123K circuit I drew above, but just to be sure, look at some data sheets for the 350. The data sheets often include several application circuits too. Mouser thinks the LM123K is obsolete, but that ain't so, at least for FAA and DOD. BTW, that exact circuit is used in one of my radar systems, except the pot was adjusted for 10v rather than 9v.

I suggest a TO-3 mounting socket and mica washer and heat sink grease if you will be operating near rated current. The socket will simplify mounting since it has the shoulder washers built into the socket.

[simonallaway]

Thanks!
The data sheet...
 http://www.st.com/stonline/books/pdf/docs/2162.pdf
... does have some application circuits. A simple adjustable regulated circuit, similar to the middle section of yours, and another one that includes diodes to protect the regulator from damage if the caps discharge into it.

That 350K is a TO-3 but at ~25mA per pedal I don't have enough pedals (or indeed a big enough stride) to exceed even 1A. I might get away with a simple internal heatsink. I used this for that wild-ass guess:
http://www.stinkfoot.se/andreas/diy/power/list.htm

I thought it was odd that Mouser didn't have it, but that's how I arrived at the 350K...their 'find equivalent' link.

[sluckey]

I might get away with a simple internal heatsink.

Yes. I just mounted mine on the chassis without a dedicated heatsink.

If you don't think you'll exceed 1 amp, just use a Fairchild LM7809, 40 cents at Mouser. Very simple, bridge, 2 caps, chip.

[simonallaway]

If you don't think you'll exceed 1 amp, just use a Fairchild LM7809, 40 cents at Mouser. Very simple, bridge, 2 caps, chip.

I think that's definitely an option. Meanwhile, I found another variant using the LM7* "family". Looks simple enough for me and it has multiple outputs:

http://img.photobucket.com/albums/v321/mattthegamer463/Schematic.png

...and the guy built it in the spirit of a tube amp..kind of 

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

[plexi50]

Thats a pretty cool looking power supply! I got the 7809 chip yesterday. But the LM123K is on backorder from the same source and original order. Lucky me. Im too busy at the moment to build the PS anyway. Soon /

[simonallaway]

Im too busy at the moment to build the PS anyway. Soon /

Me too. This amp addiction has left me with several cool projects to do and no ability to pick which one to do next! We need a separate section in the forum as an 'addiction support group' or something 

[plexi50]

Got the power supply almost finished. (2) small caps i ordered were not in the order i recieved this week. I went to Radio Shack and picked up the LM 123K. I was surprised they even had one.  Almost there.

[simonallaway]

I realise this is a very old thread, but I finally got around to making my own power supply (well, for a family member) as inspired by this post.  There are some photos in this page:

http://hotbottles.wordpress.com/2014/05/05/a-real-effects-pedal-power-supply/