Dutch Power Fuzz (switchable octave up)

[~arph]

Hi all,

Being unsatisfied with the sound of most octave fuzzes I tried/listened to I decided to cook something up myself.
This is really nothing new, but just a 2+2=5.
I took the rectifier circuit from Gus Smalley's Octave Up Sick Box. (which is just an opamp version of the transistor version seen in a lot of the octavers). I fixed the gain to about 4.7x. And removed the diode clippers. I fed the output of this via a big muff style sustain control into a bog standard gain maxed out fuzz face topology. The biggest difference comes with the 33n cap to ground from the non inverting input of the first opamp stage. This mimics the tone knob rolled back on the axe. This cap is on the same switch as the diode lift to keep treble when the octave is off. (when it is on the octave produces a lot of extra high end). Furthermore I have a resistor across one of the diodes in the rectifier (the one that is switched) to keep some bottom end when the octave is engaged. This resistor is still subject. to tweaking.

Anyways, it is a GOOD sounding fuzz and a VERY GOOD sounding octave. I hope anyone will try it.
I've attached the schematic and a vero layout. (unverified, but checked)

(ps. yes on the vero I switch the other diode in/out as compared with the schematic. This was easier for layout purposes and does not matter soundwise)

https://dl.dropboxusercontent.com/u/1849818/published_images/dpf.pdf
https://dl.dropboxusercontent.com/u/1849818/published_images/schemo.png
https://dl.dropboxusercontent.com/u/1849818/published_images/dpf.sch



Wiring looks a bit messy   

Enjoy!

Arnoud

[Cozybuilder]

Hi Arnoud- I'm going to bread it in the next day or so, I love octave fuzzes! Thanks for sharing.

[mth5044]

Thanks for sharing! I'm a huge fan of how you displayed the vero - with the black traces. That looks great and makes it much easier to read, hope it catches on.

[~arph]

Thanks guys, I hope you like it.
It should be rather forgiving on the transistors and opamp used, so use what you have/like.

I like drawing the horizontal connections when doing vero. I use color too during layout, but that makes it very distracting when you are done. But good to see if you did not make any mistakes.

[~arph]

Hi,

I have made some small changes and verified the layout. There was a huge mistake (bottom left jumper went to 9V instead of GND)
I have added a treble bypass cap (C12) on the input of the fuzz. It needed some more punch. Also I lowered the input cap (C1) to 10n so it it tighter and less muddy. On the set of 2N5088s I used I had some oscillation which I fixed by raising the BC cap (C13) on Q2 to 330pF.

That's it. working like a charm and very happy with it.

[alfafalfa]

En nu een clipje Arnoud !

( And now some sounds , please Arnoud!)

[~arph]

I know.... 

Kids are sleeping.. not the right time to fire up a fuzz. Maybe this weekend

[~arph]

Allright b!thc#s 

I did manage to record a quick sample.. Microphone was too close to the amp, but I already powered everything off when I discovered this so it'll have to do. A bit extra clipping doesn't hurt a lot when we are demoing a fuzz. Gain is at max.

https://soundcloud.com/arrfx/dutch-power-fuzz

[aishabag23]

Would you mind re-loading the files? I'm almost done building this one but the D3 orientation is eluding me. I'd like to check the schematic, but I seem to have only downloaded the vero layout  at the time. Thanks if you are able to do it!

edit: I figured it out, but I still would love to peek at the schematic if you have a chance...

Hi all,

Being unsatisfied with the sound of most octave fuzzes I tried/listened to I decided to cook something up myself.
This is really nothing new, but just a 2+2=5.
I took the rectifier circuit from Gus Smalley's Octave Up Sick Box. (which is just an opamp version of the transistor version seen in a lot of the octavers). I fixed the gain to about 4.7x. And removed the diode clippers. I fed the output of this via a big muff style sustain control into a bog standard gain maxed out fuzz face topology. The biggest difference comes with the 33n cap to ground from the non inverting input of the first opamp stage. This mimics the tone knob rolled back on the axe. This cap is on the same switch as the diode lift to keep treble when the octave is off. (when it is on the octave produces a lot of extra high end). Furthermore I have a resistor across one of the diodes in the rectifier (the one that is switched) to keep some bottom end when the octave is engaged. This resistor is still subject. to tweaking.

Anyways, it is a GOOD sounding fuzz and a VERY GOOD sounding octave. I hope anyone will try it.
I've attached the schematic and a vero layout. (unverified, but checked)

(ps. yes on the vero I switch the other diode in/out as compared with the schematic. This was easier for layout purposes and does not matter soundwise)

https://dl.dropboxusercontent.com/u/1849818/published_images/dpf.pdf
https://dl.dropboxusercontent.com/u/1849818/published_images/schemo.png
https://dl.dropboxusercontent.com/u/1849818/published_images/dpf.sch



Wiring looks a bit messy   

Enjoy!

Arnoud

[Steben]

I concur: files are gone....

It sounds killer!

[~arph]

I will as soon as I get to my laptop! ( this evening or tomorrow )

[aishabag23]

I will as soon as I get to my laptop! ( this evening or tomorrow )

This is pretty gnar on bass, I love it. I changed the 10n input filter cap to 1uf (for the sludge doom  ). Gonna put a few values on a rotary since this thing is so responsive. I'm wondering if the non-octave part of the circuit could get the squeal tamed out of it a bit. Maybe a larger power filter cap? I boxed it and the noise is still pretty insane for my taste. OPA2134 seemed "nicest" to my ears of the three or four different chips I auditioned. Even if I can't get the noise on that dialed down, I'm just going to hard-wire it in the octave on position because IT RIPS!! 

Thanks for re-uploading, and for sharing the circuit. Much appreciated.

[~arph]

Glad you like it!

Here are the files again:

https://www.dropbox.com/s/wzc106zlxf3c7c2/dpf-vero.png?dl=1
https://www.dropbox.com/s/1rbardp4vxbvaqr/dpf.pdf?dl=1
https://www.dropbox.com/s/50rvuyk3x21zk8o/dpf.sch?dl=1

I see that there is no PNG Of the schematic, only the eagle file.. if someone needs that I'll make it.

I suspect that the noise mainly originates from the fuzz circuit, it WILL be noisy when you have it at max fuzz level, but its a fuzz  .
You can lower the gain of the fuzz by adjusting the 1K 22uF combination on the emitter of q3 (the second transistor in the fuzz) or replace it with a 1k pot. one side to emitter, other side to GDN, 22uF at wiper to GND.