[2187] Second Source Transistors

Date: January 25th, 2017 | Comments : none | Categories: DIY.

In 1957, Valvo-Berichte introduced the original OC81 germanium transistor (first source) which means that any other versions of the part are second sourced (Philips, Mullard, DSI, etc). It has long been a common practice for other manufacturers to offer their own version of parts, sometimes via a license but often just as an alternate work-alike.

Just because a part is second sourced does not mean that it is a fake, as mistakenly posted occasionally in online forums. Many semiconductors are made by companies other than the original producer, and more often than not, perform just as well.

Along that same line, in opamps, a Signetics NE5532 would be first source and the TI 5532 chip would be a second source. The 7660 charge pump is another example and there are numerous copies of it available. Also, the 4558 opamp is made by just about everyone, and no one says they are fake just because the specific 4558 is not produced by the company that first introduced it (Raytheon).

The spec of the OC81d is similar to the AC128, which is sometimes listed as a substitute.



[2197] Voltage Doubler Module

Date: January 20th, 2017 | Comments : [2] | Categories: DIY.

Voltage Doubler module

Voltage Doubler assembled module
The charge-pump voltage booster module. Fully assembled and ready for installation in your pedal or project. Boosts 9v DC to almost 18v. Also provides −9v for PNP fuzz pedals and other circuits that require a negative voltage.

Order the module from the AMZ Catalog Page.



[1665] Good Band Names

Date: January 18th, 2017 | Comments : [3] | Categories: DIY.

I’ve updated the page of FREE Band Names… check it out if you need a name for your rock-n-roll ensemble!

Good Free Band Names


[2190] Tone Report Weekly Issue 159

Date: January 11th, 2017 | Comments : [1] | Categories: DIY.

Tone Report Issue 159

Issue No. 159 of Tone Report magazine has an article on how to DIY my mosfet booster. The author was very complimentary of both me and the circuit, which I greatly appreciate. If you don’t like working with stripboard, as shown in the article, there are pc boards and completely assembled modules available on my catalog page so you can build your own mosfet boost.

The pcb and modules have a refined version of the circuit that improves performance slightly.


[2178] Passive Mixer

Date: December 29th, 2016 | Comments : [3] | Categories: DIY.

Passive mixer schematic

In many applications, A simple passive mixer can be used to combine signals. The resistors R1 – R4 are used to reduce interaction of the signals but they do not completely eliminate it. The values may be adjusted higher for more isolation; try 100k for the resistors.


[2165] Power PCB

Date: October 26th, 2016 | Comments : none | Categories: DIY.

Power pcb

There are a limited number of the revised power pcb that are available. [Now in stock]

The new pcb has several improved/advanced features such as increased efficiency and an isolated output.

Order one (before they are gone) from the catalog page and the latest instructions will be emailed to you.



[2152] Jfet Buffer Modules are back

Date: October 3rd, 2016 | Comments : [1] | Categories: DIY.

Jfet buffer pcb Jfet buffer modules are back in stock!


[2144] How to Mod FX Pedals With Arcade Buttons

Date: August 30th, 2016 | Comments : none | Categories: DIY.

AMZ dpdt relay pcb

DJ Tech Tools has a new article (and video) on How to Mod FX Pedals With Arcade Buttons using the AMZ DPDT relay switch. Check it out!

How to Mod FX Pedals With Arcade Buttons


[2132] Dual Op Amp Modules

Date: August 4th, 2016 | Comments : [6] | Categories: DIY.

Opamp buffer module

Buffer, or Booster, or Direct Box.



[2124] A-B switcher

Date: May 9th, 2016 | Comments : none | Categories: DIY.

A-B switch box

My new A-B switch box for comparing pedals. (more…)



AMZ Home Page

Guitar FX PCBs