AMZ-FX Guitar Effects Blog » DIY

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.

Simple Kill Switch

admin — Fri, 28 May 2010 03:09:25 +0000

This is a simple passive kill switch that can be constructed in a tiny box like the 1590A or even smaller. The circuit is symmetrical so either jack can be the input or output. The resistors were added to make sure that the output of the circuit driving the switch was not shorted to ground, which might cause a problem with some designs. Use a normally-open momentary switch.

A 5k potentiometer can be added so that the amount of signal reduction can be adjusted. In the first version, the signal will be cut completely off when the switch is closed but the version with the pot can be adjusted so that some signal still passes through when the switch is hit.

The circuit is non-critical but a shielded box is still recommended.

Selling Pedals that use AMZ PCBs

admin — Thu, 27 May 2010 22:58:09 +0000

If you buy a pc board from me, then you can put it in a pedal and sell it. No problem! If you buy 10 or more of the same pcb in one order, I’ll give you a discount.

Also, if you are a boutique pedalmaker and you need some design work or you want custom pc boards for your pedals, I can help you out. Minimum order is 50 boards of one design. Go to my email page to send a private message.

Thanks, Jack

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

Power Supply Cables

admin — Wed, 26 May 2010 00:56:12 +0000

I found a source for some really nice, ready-to-use power supply cables that are perfect for connecting to the AMZ Power Supply. They are available at a fair price and the ordering info is available on the support page for this project.