[2314] Decapping the LM308

Date: October 19th, 2017 | Comments : none | Categories: DIY.

LM308 die shot

If you are a fan of the LM308 for use in the ProCo Rat, then you probably will be interested in reading Ken Shirriff’s blog where he strips away the layers of the integrated circuit and shows the chip’s internals.

Die photos and analysis of the LM308 op amp


[2222] Good Free Band Names

Date: September 23rd, 2017 | Comments : none | Categories: DIY.

Okay, maybe "good" is subjective, but they are FREE!

I have updated the band names page for the second time for 2017. Check it out!

AMZ Free Band Names Page

I encourage everyone to pronounced the names on the list out loud… especially if you are reading them in a public place!

Updated: Sept. 23, 2017


[2303] Modeling the Stringz-n-Thingz Synth

Date: September 14th, 2017 | Comments : [2] | Categories: DIY.

I bought the Native Instruments Kontakt sampler a while back (when it was on sale) as I wanted to use it as a multi-functional instrument. However, I soon discovered that it is also really good for creating your own sampled instruments, quickly and easily.

In fact, all you have to do is drop a sample into Kontakt’s rack and it instantly becomes a midi-controlled sampler, all created from a single sound. It is so cool.



[2299] Why Bypass Switches Pop

Date: September 12th, 2017 | Comments : [1] | Categories: DIY.

Why Bypass Switches Pop: updated to dispel the myth of static electricity.

Lab Notebook: Why Bypass Switches Pop


[2296] Emitter Follower Clipping

Date: August 17th, 2017 | Comments : none | Categories: DIY.

Electronic Design magazine has an interesting article on clipping caused by simple transistor buffers:



[2241] Mod Box Distortion

Date: July 12th, 2017 | Comments : [5] | Categories: DIY.

Mod Box schematic

I found this old distortion project while searching through a magazine archive.

Back in the late 1990s, Thomas Henry and I collaborated on a number of articles for consumer magazines. One of those projects was a distortion pedal that was published in Radio Electronics in May 1997.



[2233] Boss SD1 More Mids

Date: July 7th, 2017 | Comments : [1] | Categories: DIY.

SD-1 tone control

This is the basic tone control section of the classic Boss SD-1 distortion pedal.


[2227] SD-1 vs. TS-808 Response

Date: June 10th, 2017 | Comments : none | Categories: DIY.

SD-1 and TS-808 response

After reading a recent forum post, I got interested in the basic frequency response of the SD-1 compared to the classic TS-808.


[2213] Effects Pedal Circuits Can be Patented

Date: April 11th, 2017 | Comments : [4] | Categories: DIY.

For about the third time in less than a week, I have seen someone post in an online forum, the erroneous information that pedal circuits cannot be patented.

Yes, they can be patented, and many classic circuits started out being protected by patents. Tom Scholz, for example, had numerous patents related to his Rockman devices.

Here is a page with some pedal related patents:

50 Audio and Effects Pedal Patents


[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.




AMZ Home Page

Guitar FX PCBs