This is the AMZ Power Supply pc board. It filters and regulates a DC voltage input and provides multiple 9v outputs that are suitable to power a full pedalboard.

It can also provide a negative 9v power supply for PNP devices, and has an 18v and multiple 9v connections. Read more about this pcb that can be used as the heart of your pedalboard power supply.

Convert the noisy voltage from your wall-wart into a smooth clean source of power for your pedals!

There are a limited number of these pc boards available.

I’ve modified the instruction page for the pcb to show how to use it to build the Tillman. The instructions and parts list are on the site that is emailed to everyone that buys one of the boards. Ordering info:

AMZ MultiPurpose PC Board

The Rat is designed to have a large amount of gain and a significant treble boost. This is part of what gives it a characteristic sound, but also makes some players dislike the tone it produces.

The resistors R6 and R7 along with the capacitors C7 and C6, are the main determining factors for the low frequency rolloff.

The C6/R7 pair has a 60.5Hz cutoff.

We can see that the first easy mod is to remove C7, which will leave only the C6/R7 network determining the frequency response and gain. R6 is not in the circuit once C7 has been removed.

The capacitor is easy to find. Locate pin 2 of the opamp and follow the trace to the 47 ohm resistor. It will have bands of yellow-purple-black.  The 2.2uF will connect to it. Desolder the connections and remove the capacitor.  You could also remove the resistor.

Gain is now lower and the frequency response is flat across the band of guitar frequencies. This will give it a tone with much less treble boost, and somewhat like a Big Muff.

If the Rat has now lost too much bite for your rig with this mod, then it can be fine tuned by changing the value of C6. Remove the 4.7uF (C6) and replace it with a 0.47uF capacitor rated for 25v minimum (50v, 63v or any higher rating is acceptable too). This will give it a low pass corner of about 600Hz.

Make C6 smaller to roll off more bass – 0.22uF will have a 1292Hz corner. Use the AMZ Filter Calculator to work out a combination that you like.

Customize your Rat pedal for the best sound with your guitar and amp!

More custom mods for the Rat are available in the AMZ Muff-Rat eBook.

Update: You can apply these mods to the BYOC Mouse kit. Here is the parts cross reference:

• RAT : BYOC
• R7 = R4
• R6 = R5
• C6 = C5
• C7 = C6 (remove this one)

Make Magazine Issue 15 features DIY music projects and circuit mod information. There’s plenty of interesting info in this issue, including an article about stompboxes. They even mention me by name a couple of times

If you saw my previous post about the V-Dub circuit, then you know what these boards are all about. They are 9v to 18v charge pump converters that will power a single pedal. I have a limited number of them to sell – you get a single populated pcb as pictured above which you can wire into a suitable enclosure or pedal. They are approximately 1.9″ x 1.03″ and will fit in the small Deltron diecast box, Mouser part no. 400-4590.

The updated and revised pc boards are RoHS compliant and now available for purchase.

Thanks!

Double your voltage, double your fun!

Here is the completed AMZ voltage doubler in a mini-box. To give you an idea of the size, a 9v battery is a little bigger than the green foam pad in the bottom unit.

The camera flash reflected off the metallic particles in the paint and made the finish look weird – it’s not really sparkly like that. There are a few bubbles in the decal, probably because I did not let it dry long enough before going to the clearcoat step. Or maybe because my decal paper is a bit old.

Anyway, the unit accepts a 9v input on one side and outputs 18v on the other. It goes inline between your power supply and any pedal that you want to run off a higher voltage. It is a basic charge pump circuit with a few extra frills that help keep the output voltage clean and hum-free.

Using one of my switching power supplies, I measured 9.0v on the input side and 18.03v on the output under no load.

I did live tests with several pedals in my studio and really got some great new sounds. An 18v power supply can make a simple booster pedal run cleaner and with more oomph… send your amp into interstellar overdrive!

I have a handful of these boards on hand and I may sell a few or even organize a giveaway. I haven’t decided.

The updated pc boards are available here.

Edit: The photo below shows the doubler next to a TS-9 for size reference.

They are for an inline voltage doubler that will convert 9v to 18v for powering your effects pedals. The circuits on the two boards are actually identical but I ran out of the miniature capacitors used on the bottom board and had to go with the slightly larger blue ones shown on the board above.

More info when I get them mounted in an enclosure.

AMZ goes solar – Part 2!

Shown above is my $12 solar battery charger, which was previously mentioned on this blog, connected to a 12v rechargeable battery.

I salvaged the battery from a backup power supply from my office. These cheap backup power units go bad with alarming frequency and they are too cheap to repair. However, the battery usually has a lot of life left in it. I saved 3 or 4 of these batteries and now have cheap power that can be renewed at virtually no cost with my solar charger.

The battery is 12v rated for 7 amp-hours. This is more than enough to power a pedalboard for many hours.

I made a simple voltage regulator box to convert the 12vdc to 9v. That is a project for another time once I get it finished and have some pictures to show.

Check with your company IT department; they will probably give you a similar battery from their salvage pile.

Here is a shot of my new solar battery charger connected to a rechargeable 9v battery. I’m using these special batteries for all of my pedal testing.

The charger came from Harbor Freight and cost $12.

The rechargeable 9v was found on Ebay.