[2510] 9v Isolated Power

Date: February 7th, 2019 | Comments : [2] | Categories: DIY.

Details of my 9v isolated power converter now in the Lab Notebook.


[2500] What is a Preamp?

Date: February 1st, 2019 | Comments : [3] | Categories: DIY.

In the last year or so, I have noticed a number of new pedals being introduced that are being called preamps. So what is a preamp, and can a pedal serve as one?

In audio applications, a preamp is a circuit that amplifies very weak audio signals to a level that will drive a power amplifier to its rated capacity.



[2481] Amp In A Box

Date: December 19th, 2018 | Comments : [1] | Categories: DIY.

The concept of a pedal that sounds like an overdriven amplifier has been around a long time, and in the late 1990s, I contributed to the field with several designs. The most influential of them has to be the Booster 2.5 pedal, which was a derivative of my earlier Mini-Tubes Preamp.


[2470] Fake LM308

Date: December 13th, 2018 | Comments : [4] | Categories: DIY.

Fake LM308 in a Mooer pedal… well, not an original National Semiconductor chip anyway.

So, is it a fake if you mark a plain cheap op-amp that meets or exceeds the specs of the original LM308 with that part number but the internal circuit is not the same?

It will work in circuits designed for the LM308 and perform well. It does the job. But at the fringes and limits of the electrical characteristics where many fx pedals operate, it will not be the same as an IC with the internal circuit design of a real original NatSemi LM308. Is that a fake or just a poor substitute?


[2459] Hackspace magazine

Date: November 30th, 2018 | Comments : [2] | Categories: DIY.

A great resource about building stuff, including electronic projects, HackSpace magazine is packed with projects for fixers and tinkerers of all abilities.

You can get FREE issues at:




[2449] The Business of Making Pedals

Date: November 29th, 2018 | Comments : [5] | Categories: DIY.

Why are US-made pedals significantly more expensive than Chinese clones?

TL;DR: Chinese companies receive subsidies from China’s central and provincial governments. They also have an artificially low currency-exchange-rate, smaller profit margins, few worker safety programs, little environmental control, low taxes, low wages, long hours and few worker benefits, so the price of Chinese products will always be lower than similar products made in the USA.



[2435] Hum, Whine and Noise

Date: October 10th, 2018 | Comments : [1] | Categories: DIY.

I often see people post that their pedal is making a noise, but they fail to describe the sound adequately to allow anyone to decipher the cause. For example, a hum is low pitched and is often caused by a poor ground connection or bad cables. A hum sounds like this (you may need to turn down the volume):



A noise caused by power supply aliasing, as from a poorly designed charge pump, or from radio frequency interference will be higher in pitch and often sounds like this:



Another common noise is a random background hiss. All electronic components generate a very small noise voltage and high gain circuits can make the sound much more prominent, like this:



Recognizing the type of noise your pedal is producing is the first step to working out a solution to the problem!


[2419] PT2399 Analysis

Date: July 30th, 2018 | Comments : [1] | Categories: DIY.

PT2399 delay chip

ElectroSmash has published a thorough analysis of the PT2399 delay chip, which has been used in many echo and delay stompboxes.

For those who would like a copy to keep on hand when working offline, I have converted the article to PDF format and it is available for free download here.



[2423] Metro Songs Podcast with Janglebox

Date: July 26th, 2018 | Comments : none | Categories: DIY.

Steve Lasko, creator of Janglebox, is interviewed on the Metro Songs Podcast episode 5. It’s an interesting talk with plenty of behind-the-scenes info.

Near the end, Steve even lets the cat out of the bag that I designed the J-Gate pedal for him. Smiley

Check it out!


[2414] New Tariffs on Components

Date: June 21st, 2018 | Comments : [1] | Categories: DIY.

Bunnie Huang says that new tariffs coming July 6th will hurt educators and makers, and encourage offshoring.

“It taxes the import of basic components, tools and sub-assemblies, while giving fully assembled goods a free pass.”

New US Tariffs are Anti-Maker and Will Encourage Offshoring



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