My Big Muff mod

[Basstyra]

Hello !!

I'm new here, I introduced myself a little in the lounge. Here is my first DIY project (not really my first to be honest, but the first to be that big, and ton include the sound path). Finished this week-end, but there may be other improvement to make.

So, the object : a russian Big Muff, bought 35â,¬ shipping included, so quite cheap. A perfect ground to learn stombox diy...

First, I added, almost as soon as I got it, a DC input, Boss type. I power it with my Boss LS-2 and a daisy chain. Quite simple, but as I like to understand what I'm doing, I asked several question and inform me about how pedals are powered. I changed the jacks as I was there, they were horrible...

But recently, I wanted to go further. I'm student in electrical engineering, and theorical teaching is cool, but... I wanted to put my hands on real project.

The muff, as you know, eats all the bass frequencies, the presence and the attack, on a bass. I used my muff with the Boss LS-2, adding a unity gain // dry loop to it. My bass sound + the muff sound, instead of only the muff sound. It keeps my presence, my attack and so on. What I did is to include this function in the muff.

I started with the Moosapotamus page : http://www.moosapotamus.com/paraloop/paraloop.htm (thnaks to him. I also find this forum thanks to this page). But this looper wasn't what I was looking for, so I started from that but did my schematic by myself.

Here is my current schematic. It's working, not perfectly, but working. The input and the output are directly on the bypass relay.


Here is the circuit :


Rear view :


The bypass, with a relay :


The inside (in fact, some parts are missing there, I changed some things, because I had a terrible "POC !!" when I bypassed. It has been fixed with the final resistor (1M) on the schematic and a cap between the relay and output jack).


The Muff, finished. Notice the blue led, a "tuning" mod suggested to me by Fozzy, from Talkbass.com forum) :


Technical stuff : the caps are 100nF ceramic. The resistor to bias or ground 1M, the other 10k. I found the relay (5 volts, that's why I add a resistor on the switch) in a broken modem. the additional pot controls the volume of the dry loop, from 0 to unity gain. The opamps are tl072, not the best, I may change them later.

The sound : there is... hm, I don't know how to say that in english... In french, we say that  there is "blow" ("souffle" in french). There is noise when I don't play, what is the english word ? Noise, maybe ? We use the word noise ("Bruit" in french), but for musical applications we use the word "souffle".

So, there is noise. I don't really mind, the purpose of the muff is to do noise !!    :twisted: I had a "pop !!" bypass problem, solved with a cap and a resistor to ground at the output of the schematic. But now it works, I have my bass sound plus the muff sound, what I like, I'm quite happy ! The bypass isn't perfect, the cap I added is in the way even when I bypass, but well... Maybe I'll see this later.

So, this is my first mod. I'm very happy, I managed to do things from my hands, I applied the theorics stuff my school teaches me on a real project, and I modded my favourite pedal, it sound the way I want now !!      

Thanks or having the courage to read all this !    :wink:  Any remark would be apreciated !

[mrsage]

Wow, very cool mod!

Perhaps you mean there is "hiss" in the signal?

Looks like a fun mod, though!

[Basstyra]

Yes, "hiss" seems to be the word, thanks !  :wink:

[Bernardduur]

You can get a really nice cool "noise" effect (including octave up and down functions at random) by bending the Q2 and Q3 (don't know wich leg). I have also a mid boost mod somewhere. I'll search when people are interested.

[Bernardduur]

Found mid-mod fast:

Addition to my R5 mod: Replace resistor 5 with a 3.3k resistor, add a 22k (lineair) pot behind it (hot - 3.3k - pot - ground) and you can cut out the mid-drop the BMP has; for best results replace the 4000 pF cap (3900 pF to be exactly) with a 0,015 muF cap. The sound is awesome!

[Basstyra]

Hm, maybe I'll try this somedays. I have other projects fo now, but why not later...  

[hattori]

Nice, very nice ....

hatt0ri
(known as Fozzy on talkbass.com forum)

[Basstyra]

Hello guy !  :wink:

[hattori]

Still waiting for the sound clips

[Basstyra]

Yes... shame on me, I didn't make them last weekend, and now I don't have it there... I have to do this this coming weekend.

I think I'll do a comparative with the muff alone, the muff+LS-2 dry loop, the muff+ my dry loop (thoses two should be the same), and my dry loop compared to the bypassed sound, to hear the hiss. I'm pretty busy thoses times, but I can do this if I force myself to do it !! Several people asked for soundclips, I have to do them... I'll do, I promise...  

[Mark Hammer]

Bienvenue!

A-tu essayé d'utiliser deux paires de diodes (2+2, au lieu de 1+1) dans les étages du distortion? Ça pourrait augmenter la gamme dynamique, qui pourrait ameliorer le son pour un contrebasse.  C'est juste une idée.

Il me semble aussi que les fréquences choisies pour les deux filtres compris dans le controle de tonneur pourraient être mieux selectées.  Mais, honnêtement, j'ai aucun idée dans quelle direction.  Plus haut, plus bas?

Est-ce que le "souffle" et le "bruit rose" sont pareils?

Mark

[aron]

Very nice Big Muff mod! That case is so big so you can add additional circuits, no problem.

[Basstyra]

Salut !
Ca serait pas plus sympa pour les autres de parler en anglais ? Enfin j'en sais rien, j'imagine que tout le monde ne parle pas francais. Enfin je sais pas comment ca se passe ici pour les langues...

J'ai rien testé pour modifier le son de la muff en elle-même. Je verrais ca plus tard, c'etait pas mon but, la. Mais j'ai plein de pistes, pour plus tard si l'envie m'en prend.

Le souffle et le bruit rose, c'est pas tout a fait la meme chose. Un bruit blanc, c'est un bruit qui a la meme energie sur toute bande de fréquences (cas idéal, dans la pratique la bande passante n'est jamais infinie), en plus clair dont toutes les fréquences sont au meme volume. Un bruit rose c'est un bruit blanc avec une petite dominance d'une fréquence. Ce qu'on appelle le souffle, c'est juste du bruit, mais c'est le bruit qu'on capte sur le chemin du signal, amplifié par l'ampli, qui augmente plus ou pousse le volume.

In english :
I think it would be more kind for the others to speakin english, I doubt a lot of people here speak french. And we're here to share, no ?

I tested nothing to modifie the sound of the muff itself. I'll do some tests maybe later, I have a lot of ideas, but not right now.

The "pink noise" (bruit rose) isn't just a noise or a hiss. A "white noise" (bruit blanc) is a noise with the same energy on every frequency band (ideally, because practically, the bandwith isn't infinite). More clear : it's a sound in which every frequency is at the same volume. A "pink noise" is the same, with a little more of one frequency. The "souffle", I think the right translation is in fact the hiss, is the noise specially situated on the signal path, amplified by the amplifier, which increase in volume when you turn the volume up.

[Basstyra]

Ok, here is the end :

The final schematic :




The perfboard plan (the numbers are placed on the schematic just up there) :


And some soundclips :

My jazzbass dry. The muff without dry loop. With dry loop. With and without (I turn the dry loop volume while I play, the sound difference is obvious). Up the neck without. With, here it is the most obvious.

Settings : sustain at 3 o'clock, tone at 3 o'clock down the neck, and max (5 o'clock) up the neck.

The advantage of this mod is more obvious on a bass amp than on a computer. And with a drummer and guitarist, it becomes simply excellent.

Sometime I cut the dry loop during rehearsals, just to remember me how it was, before...

http://perso.wanadoo.fr/jumping-jack/autre/elec/modedmuff.mp3

With a pick, the attack difference is even more obvious :
http://perso.wanadoo.fr/jumping-jack/autre/elec/modedmuffpick.mp3