Showing posts with label Theory. Show all posts
Showing posts with label Theory. Show all posts

Relay Bypass: final code

After the crowdfunding campaign, I decided to update the relay bypass code.

Indeed, this first version was nice, but one main drawback that was feedbacked to me is that the switch was activated on release, which was not always very intuitive or easy to handle. Moreover, I wanted to add a "temporary" bypass option in the Montagne Tremolo.

Montange Tremolo Relay Bypass

In this post, I am going to explain a bit the new code and to show you how I did it.

If you have not read my post about Relay Bypass, I highly recommend you to read it before reading this post. All the basics of microcontrollers are presented there.

  Tip! The full code is available on Github. With the relayonpress.c and header.h files, you will have everything needed to code or burn chips.

If you already have a GitHub account, you can Star the project for updates, or Fork it to modify it and make your own Relay Bypass code.

Lets go!

Ground loops and guitar pedals

Yesterday, I received an email from a beginner that decided to make his first guitar pedal. I always enjoy this kind of emails and answering questions is part of the game. This time, he asked me a question that I had several times: "my circuit is noisy, could it be a ground loop?"

Ground loops are part of the legends and myths around DIY guitar pedals. When asking about noise in a setup, it is the most common answer, and is supposed to be the main cause for hum, hiss or other noises that you can have on your first circuits.

Montagne Tremolo PCB

So I decided to write a post about it, starting from the begining:

Tonebender MKIII clone (Aion Electronics Phobos)

Here is my last build: a Tonebender MKIII clone! The tonebender was initially a derivative of the Fuzz Face, a bit closer to an amp distorsion than a fuzz. (read my post about the different types of fuzz) It became quickly famous thanks to a lot of guitarists like Jimmy Page or Jeff Beck.

The MK2 version used two germanium transistors to get fuzzy tones. However, due to the nature of the circuit, the quality of the fuzz was very dependent on the transistor's gain and characteristics, just like in the Fuzz Face. In order to avoid the selection of transistors, the Mk3 version used 3 transistors, so that the quality of the sound is less dependent on the germanium transistors used. Here is my version:

Tonebender MKIII clone Aion Electronics Phobos

Relay bypass with anti pop system: noiseless and clickless true bypass

Did you like my post about relay bypass? At least I did, and now I use it in almost all my pedals! Thus, they are longer lasting, and we avoid the mechanical noises of a 3PDT. However, I noticed something annoying: the relay bypass makes more "pop" noises than the 3PDT, especially with high gain circuits...

Indeed, relays tend to switch from one state to another much quicker than big mechanical 3PDT switches, which causes the "pop" noises to appear. The gainier the pedal, the more it will amplify the pop and make it louder.

So I adapted a system that I have found on Stompville that suppresses all these noises. Here is the result, with a (very) simple "before and after" video:

Tap tempo tremolo DIY: a complex project!

I am currently prototyping a tap tempo tremolo that I conceived. It is quite a big project, and I have been working on it since nearly 6 months now! Like many guitarists, I really like the warm vintage sounds that you can achieve using tremolo (like in "Bang Bang" from Nancy Sinatra), but also the choppy madness that you can get with square waves, like in "Know your enemy" from Rage Against The Machine, or even weird stuff with high speed tremolos... A really cool effect!

I play regularly in a band, and my point of view is that tap tempo is just absolutely needed for rhythmic effects like delays for instance. Thus, I decided to add one in my tremolo. It is not easy to implement a tap tempo, as you have to use digital circuitry, as we will see later... Here is my current prototype:
DIY tremolo with tap tempo
That is a lot of knobs! You can already notice that there are two footswitches: tap tempo (right side), and the true bypass footswitch that is a clickless relay bypass system! I used the relay bypass system that I conceived, which is completely silent, and more reliable than classic 3PDT true bypass. Indeed, 3PDT footswitches are the main reason for guitar pedal failure. The little switch in the middle of the two LED (bypass LED, and tempo LED) allows you to switch the pedal temporarily. This is nice to add some choppy stuffs while you play!