AMZ-FX Guitar Effects Blog

AMZ Power Supplies

admin — Mon, 23 Aug 2010 01:51:55 +0000

I built a couple of power supplies with the AMZ power pcb; one for a friend and the other for my own use. Those boxes are 125B size diecast aluminum, and painted with white spray paint. The one in the front (mine) has an overcoat of a strange clear color-changing paint that is difficult to photograph, and I did not care much for the finished look. The other was painted white then overcoated with a transparent Duplicolor yellow that gave a nice aged look. The effect is so good that I plan on using it on my next pedal build.
Power

Copr. 2008 by Jack Orman Visit my site to learn more about guitar effects, download free projects or buy pc boards and germanium transistors.

Sanyo Pedal Juice

admin — Wed, 18 Aug 2010 03:04:21 +0000

This is the Sanyo Pedal Juice, which is a rechargeable battery pack intended for guitar effects and music related hardware. The basic idea is to provide a clean stable power source for your pedalboard without having to worry about dead batteries or cumbersome power supplies.

The complete system includes a battery pack and a wall adapter (shown here) that is used for recharging. It takes about 3.5 hours to get a full charge on the battery.

The plug on the adapter is a smaller size than the power outputs, which will prevent accidentally connecting it to the wrong jack.

The battery pack is almost exactly the same size as a 125B aluminum box used for many booster pedals (4.7" x 2.56" x 1.65").

There are two standard 2.1mm power jacks that provide the 9v pedal power. One good feature is that the battery pack has a button that allows you to power down all of the pedals connected to it without having to unplug them.

The multi-color LED indicator on the battery pack glows green, orange or red, depending on how much life is left in the battery. The capacity of the power pack is specified as 50 hours at 10 ma., or 17 hours at 100 ma. Each power output can provide 2000 ma, which is more than enough for even the most power hungry pedal. It also has a current limit on the outputs which will break the connection if current in excess of the 2A rating is drawn from the power ports.

Another nice feature is that the power pack will automatically shut down after 10 hours, which prevents totally draining the battery should it be left on after use.

The battery is a 3.7v lithium-ion device, which means there must be a step-up regulator inside to get the 9v for the outputs. The voltage output is filtered so that it is clean and free of noise.

The only negatives that I see for this unit are that there are only 2 power outputs, though you could use a daisy-chain cable to provide more connectors, and you cannot use the unit to power pedals while it is charging.

The unit is solid and well made, and though it only has a 1 year warranty, it should last well beyond that time.

Copr. 2008 by Jack Orman Visit my site to learn more about guitar effects, download free projects or buy pc boards and germanium transistors.

Superhot Mosfet Boost

admin — Sat, 07 Aug 2010 13:03:02 +0000

This is a copy of a page from the Analog Music Projects Newsletter, that I first published over 9 years ago, which shows a high gain mosfet mini-booster type circuit. I saw something similar at DIYstompboxes and thought I would point this out to the purchasers of the newsletter to review if they are interested in the subject and would like to see more info.

The AMP1 newsletter also describes how to make bipolar silicon and germanium versions, as well as more than a dozen variations of srpp or mu amplifiers. Check it out!

The top transistor can also be a mosfet device, which gives you an all-mosfet mini-booster.

Start out with R3 = 1M and R4 = 2.2M to bias the upper mosfet. Try this with two BS170 transistors for a clean unique sound.

Boss DD-20 Gigadelay Power Problems

admin — Mon, 19 Jul 2010 15:02:27 +0000

The Roland Boss DD20 Gigadelay causes power problems for a lot of people on many different voltage adapters. It is most happy on its own power supply but with a few circuit changes, the AMZ power supply can provide the needed voltage to the pedal.

Since we don’t know what is inside the DD-20 on the power supply input, we can only guess about the design and what is causing the problems. It seems the pedal is creating instability with the regulators, likely by setting up a high frequency oscillation that causes overheating and eventual shutdown.

A few modifications can adapt the power supply to work with the Boss pedal and a complete description of the mods is included with the technical material supplied with the power supply pcb purchase.

The mod has been tested and verified to work with the Boss pedal.

AMZ Power Supply

Copr. 2008 by Jack Orman Visit my site to learn more about guitar effects, download free projects or buy pc boards and germanium transistors.

Cleanest Boost Pedal

admin — Tue, 06 Jul 2010 14:11:53 +0000

I often see this question on pedal forums: What is the cleanest and most transparent boost pedal?

One limitation of stompboxes is the 9v power supply. It sets a limit on the voltage swing that can be easily exceeded by a modest amount of gain (boost). The result will be distortion. There is an article in the Lab Notebook which goes into more detail about this.

The most common way to add clean headroom to a pedal is to power it with a higher voltage supply, such as 18v from two batteries. This will practically double the amount of signal available before distortion occurs.

So, if we decide to pursue clean, transparent output with 18v power, I would recommend these boosts in order starting with the cleanest:

(1) Opamp booster
(2) Mosfet booster
(3) Mini-booster or bipolar circuit

PC boards are available to make projects for these circuits on the AMZ order page. The mosfet and mini-booster selections are obvious and the opamp or bipolar are made on their respective multi-purpose boards.

Even at 9v, I would suggest that the order above is correct for finding a clean booster pedal.

Copr. 2008 by Jack Orman Visit my site to learn more about guitar effects, download free projects or buy pc boards and germanium transistors.

True Bypass with Relay

admin — Tue, 29 Jun 2010 19:57:04 +0000

This is a project that I developed about 2 years ago for a rack amp system I was working on that has been put aside for now, so I decided to adapt the circuit for pedal use since the programming for the micro had already been done.

This is a 1″ x 1″ pc board which holds an AVR microprocessor that is controlling a latching DPDT relay. The LED indicator on the pedal is also driven by the micro. The soft-touch momentary switches that are shown several posts below were bought for this project.

You can use the pcb to build a new pedal, or retrofit it into a Boss or Ibanez box to give them true bypass.

More info is available here.

Copr. 2008 by Jack Orman Visit my site to learn more about guitar effects, download free projects or buy pc boards and germanium transistors.

AMZ Un-Buffer

admin — Tue, 29 Jun 2010 15:15:36 +0000

Back in 2002, I published an article about pickup simulators in the Lab Notebook. The simple circuit can be built in a small metal box with in and out jacks and used as an “unbuffer”…

This means that the output of a buffered pedal can be converted to have the characteristics of a guitar pickup, and it will react with the circuit following it as if the circuit were being driven directly by the guitar – in other words, un-buffering the buffered pedal.

The article in the Lab Notebook has another version of the pickup simulator (unbuffer) that includes volume and tone controls. This will allow you to roll back on the volume to get the same interaction as from the pickups/volume.

It’s completely passive; no battery or power supply jack is required.

Put this circuit in a small metal box and remove the buffered effect of your pedals!

Copr. 2008 by Jack Orman Visit my site to learn more about guitar effects, download free projects or buy pc boards and germanium transistors.

AMZ Power Supply Project

admin — Wed, 02 Jun 2010 08:48:46 +0000

First pictures have been submitted of a completed power supply using the AMZ pcb. Thanks to Gordy for permission to post his pix. Nice job!

Note the small hole on the bottom of the enclosure. This allows adjustment of the sag trimpot without having to open the box.

Copr. 2008 by Jack Orman Visit my site to learn more about guitar effects, download free projects or buy pc boards and germanium transistors.

AMZ Tweed Stack PCB

admin — Wed, 02 Jun 2010 01:40:24 +0000

First look at the new AMZ Tweed Stack pcb. This project is an update of the classic Booster 2.5 combined with some of the features of the Mini-Tubes Preamp from the AMZ-CD. Several boutique builders offer commercial boxes that are based on this classic project, and this pcb will have plenty of mods to apply to the circuit.

Make a high gain stack-in-a-box or a smoother less distorted analog amp sim. Coming soon!

Copr. 2008 by Jack Orman Visit my site to learn more about guitar effects, download free projects or buy pc boards and germanium transistors.

Multi-Fuzz Update

admin — Wed, 02 Jun 2010 01:34:22 +0000

Here’s a sneak peak at the first project based on the Multi-Fuzz pcb. Some basic testing has been done and now it’s ready to mount in an enclosure.

Copr. 2008 by Jack Orman Visit my site to learn more about guitar effects, download free projects or buy pc boards and germanium transistors.