Big Muff circuit going to fab!

Here is my new Big Muff PCB!

Remember when I was telling you about PCB development? (yes, long time ago...) I finally finished one! It took me a lot of time, but now I am satisfied with my layout:

As some of you recognized, this is a Big Muff circuit! I decided to add an optional forth knob: the mid knob. I can decide whether I want to add it or not, simply by adding a jumper if not (and then, the tone potentiometer can be wired in the center of the pedal). Maybe I will add another optional feedback mod, allowing to connect Q1 emitter to Q3 emitter via a switch. It creates a nice noisy feedback, ideal for sound experimentations...

The circuit is exactly the same as a classical Big Muff, I just added the mid knob in the tone stack, and some components for polarity protection and voltage stabilization. (on the top-left part of the PCB) I will rename the components so their number will be the same as the one used on the Big Muff Page, so you can easily make any version of the Big Muff you like, or modify it with their great circuit guide.

Capacitors sizes were chosen bigger than needed, so they can be swapped with other value to fit any Big Muff model (Russian, Ram's Head, ...etc). Note the funky logo I made because OshPark is not able to use imported images...  Anyway, it is still nice!

I receive the first batch of prototypes:

It is a very compact build! It can fit a 1590B enclosure (well, I hope so...), or at least a 125B with top mounted jack. For now, I ordered a test batch of 3 PCB in oshpark, and I plan to test it as soon as possible! If it works correctly, I think I will produce a small serie of PCB.

As you may know, PCB are cheaper if ordered in large quantities. If you are interested in buying one PCB (or more!), send me an email, so I can adjust the number of PCB I will order! Price will be around 5-8 euros for the first batch (depending on the number of people interested), with a 1 euro shipping cost for France, and 3 euros abroad.

I first designed this PCB for personal use, but it can be a win-win situation if people are interested.

For now, I am thinking about the logo I will use, I thought of this:

I noticed that the "Pi" symbol, looked like a lot a Dolmen... Which is also convenient for a Fuzz that has been used by many stoner guitarists, including ones disguised as druids (Sunn o))), anyone ?). Maybe I will have it laser cutted in black or red (maybe purple for a "violet era" rams head), in order to have 2/3 different version. A bare aluminium version with the red logo that will be the "vintage correct" version, following a classic 73 ram's head fuzz schematic, and a black logo on a black or dark green (russian) box for a "doomy" version, very bassy and gainy.

Let me know what you think about it, post a comment!

LPB1 mini PCB !

The LPB1 (Line Power Boost 1) is a boost pedal that was commercialized in 1968 by Electro Harmonix. It is the first boost pedal using a silicon transistor. Indeed, previous boosts like the Dallas Rangemaster Treble Booster were using germanium transistors. Another novelty with this pedal was that it was boosting all frequencies and not only trebles, making it the first clean boost available!

 

The circuit is really the most simple one you can imagine for a boost:

First, there is a 0.1uF coupling capacitor that prevents parasitic DC current from the guitar to go in the circuit. With the R2 resistance, it forms a high pass filter : by changing its value, you can modulate the amount of bass going through the circuit. If you increase C1 value, more bass will go through, and vice versa.

Then, there are two resistors forming a voltage divider (R2 and R1), to provide a certain voltage to the base of the transistor. Here it is : R2/(R2+R1)x9V = 43/(43+430)x9=0,81V at the transistor's base.

The silicon transistor is a 2n5088 (originally a 2n5133 - same transistors that were used in the Big Muff later), wired as a common emitter. R4 and R3 will define the amount of amplification. If you increase R4, amplification will be larger. If you increase R3, there will be less gain.
A second 0.1uF coupling capacitor that prevents DC current from the battery to go out of the circuit. Finally, a 100k potentiometer wired as a variable resistor defines the final volume.

If you look carefuly, you can see that the last stage of the Big Muff circuit is exactly the same! A LPB1 circuit is used to increase the final volume.

Indeed, this circuit can be used in a lot of different effects to boost the entry or final level. A fun thing to do is to add a LPB1 boost before a saturation effect to increase the gain. It is very fun on a Big Muff (like in the Musket Fuzz or Supercolider fuzz), or on a Tube screamer (like in the Fulltone Fulldrive)!

In order to be able to add this little circuit when I want, or to test it on several pedals, I decided to make a small PCB that allows you to add a "boost" knob on every pedal you want. There is a "in" and a "out" pad that allows you to place it anywhere in a circuit:

I will test it on a Big Muff or a Jan Ray! I could also try to see if it can fit a Hammond LB enclosure (super small squared enclosures like the one I used for my Strymon Favorite switch) Note that there is no voltage stabilization or polarity protection system on this board (too small, not enough space for it!), so do not hesitate to wire a 100uF capacitor between the two lugs of your power supply input.

I should receive all the parts to test it soon...

Klon Centaur buffer boards

Today I just received my first PCB conceived by me! A really simple Klon Centaur buffer.

I never really used a buffered pedal before having some boss pedals or my EHX soul food. I want to try whether it really changes something when placed at the beginning of the chain. But the main reason why I choosed this circuit is because it is a really simple one.
I am really satisfied with my layout, a lot of geometry going on here, every component just fits! It is really a small PCB, I wonder whether it can fit in a 1590LB enclosure... Seems possible! 
For now I am planning to use it in a patch box for my pedalboard, to use it as an optional buffer at the begining of the chain.
I did all the work on eagle, so maybe I will write down a short tutorial soon.

PCB development

I am currently working on conceiving PCB with Eagle software.
It will allow me to have some backup PCB of circuits that I make often or for specific projects. Also, PCB are really easier to work with than veroboard, and look much more professional!
And what a satisfaction to have something that you made up from scratch!

Will you manage to recognize on which circuits I am working on?

 

There are still a few changes to do to be sure that everything fits, components in the PCB, and PCB in the enclosure!
To do that, I will have to order the components and enclosure to test with printed PCB glued on cardboard.
If everything is OK, I send it to fab and cross fingers !

Laser engraved plates

I recently ordered some laser-engraved plates with the Coda Effects logo. I have ordered through HPM laser, a french company, which was affordable, and people there were really helpful and patient ! (not easy to know exactly what you need in some cases !)

Here is the result before cutting everything:

Ink was projected with the laser on a stainless steel plate. The result is really neat and with 3M double-sided tape, I can stick it to any pedal enclosure I made for a really professional looking stompbox !

Dead Astronaut FX Chasm Reverb PCB

Today I received a PCB from Dead Astronaut FX, the Chasm Reverb!
Dead Astronaut (alias Robert Henry) is an effects builder based in the United Kingdom. He builds a lot of different effects (fuzz, distorsion, tremolo, delays...), with beautiful etched enclosures.

I recently had a crush on the reverb he makes, the Chasm Reverb. It is a beautiful, deep sounding reverb that can auto-oscillate to create great sounding "waves" of sounds, ideal for post rock or prog rock. It is based on a Belton Brick, an IC allowing builders to make digital reverbs. Moreover, it has interesting options compared to other reverbs: a mix potentiometer to choose the amount of dry and wet signal, and a bypass system that let the reverb ends when you turn the effect off. It is called "trails". There is also a "damp" setting and volume.

You can find demos on youtube (chasm reverb or prismatic reverb) that are really great sounding!

Dead Astronaut can make the Reverb for you, or you can order a PCB to make it yourself. As being a DIYer, I ordered the PCB for a reasonable price of 11 pounds. If you want to make one, you can buy the PCB here. Robert is very helpful and replies quickly to emails, he gave me a lot of useful informations. The PCB is of very good quality, double sided with a nice ground plane. The Chasm reverb layout is quite nice, and not too compressed:

We can see the big space necessary for the Belton Brick

(Digital Reverb IC)

 

The circuit is nice seen from the bottom too!

I started to populate the board. I could add every resistance, but I miss some diodes types and capacitors values. And of course the Belton Brick!

I am really looking forward to hear it!

Dead Astronaut's website:
http://deadastronaut.wix.com/index