Catalinbread - Merkin Fuzz  [traced]

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blanik
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Post by blanik »

Here are pics of the Merkin Fuzz to get the ball rolling, i really like this fuzz, specially the texture knob, it really dials all typical fuzz sounds, from farty gated sounds to really high gain FF/Fuzzrite or even muff type sounds without the sustain, here's some info:

three 2N222A transistors
input cap is 473 (so is the one right next to it, followed by a greenish 0.0022uF cap)
all peripheral electros are 47uF @ 50V, the central electro is 10uF @ 50V (the greenish cap right of the central electro is 0.0047uF
the output cap is 104
both volume at texture pots are 500KB, volume is at the end of circuit in the typical fashion
five 470k
one 2k2 (LED)
two 47k (one looks a bit like a 46k but most likely a 47k)
one 4k7
two 1k
one 22k
mf1.jpg
mf2.jpg
mf3.jpg
mf4.jpg
mf5.jpg
mf6.jpg
mf7.jpg

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salocin
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Post by salocin »

First pass. Unverified. Will breadboard it in the next few days.

I assume the transistors are 2n2222 not 2n222 ?
CBMF1.png
CBMF1.png (4.66 KiB) Viewed 4532 times

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culturejam
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Post by culturejam »

Interesting!

Help me out here. It looks like that Texture control is a hybrid gain/tone control. On one side of the sweep you'd get all the output from Q2 and more bass, and on the other side you'd almost totally bypass Q2 and have more low end rolled off from the smaller coupling cap (2n2 vs 47n).

Is that about right?

Also, are those resistors set up as voltage dividers on all three collectors?

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blanik
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Post by blanik »

oups, you're rite, they're 2N2222A (on the transistor it's written on two lines)

something like that:

.P2N2
222A

two more details, i've check the board outside (daylight is better than houselights) and the resistor i wasn't sure is indeed a 47k, the purple line had a different tint to it

and on the schematic, the filter cap is a 100, on the pedal it's a 47uF but i guess anything over 47uF will work...
:-)
Last edited by blanik on 21 Sep 2010, 14:17, edited 2 times in total.

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blanik
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Post by blanik »

culturejam wrote:Interesting!

Help me out here. It looks like that Texture control is a hybrid gain/tone control. On one side of the sweep you'd get all the output from Q2 and more bass, and on the other side you'd almost totally bypass Q2 and have more low end rolled off from the smaller coupling cap (2n2 vs 47n).

Is that about right?

Also, are those resistors set up as voltage dividers on all three collectors?

when playing with the pedal's texture pot, when fully counterclockwise the sound is a fuzz-overdrive hybrid, just a bit gated with lots of mids, as you turn it up, it becomes fuzzier and more gated but the mids go away a little, you have to compensate with the volume, a little past halfway the sound is less gated, more fuzzy but no mids left, scooped like a BMP, lots of treble, full clockwise the sound is really high gain, with lots of mids, "the stooges zone" lol

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Post by HEAD »

Hi,

Just for fun I made a quick vero layout for it at coffe and cookies.:) Still unverified as it is! Referring to blaniks schem. Tell me if you spot any errors - I'm pretty sure there are some... if not many.:D

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culturejam
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Post by culturejam »

This might a record. :lol: :mrgreen:

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blanik
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Post by blanik »

the texture knob arrow is the other way, when maxed the wiper is connected to the .0047uF (invert the lugs 1 and 3 on the vero), for the schem i've checked it with my pedal and except for the texture pot direction, it seems to be ok
Last edited by blanik on 21 Sep 2010, 16:00, edited 1 time in total.

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HEAD
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Post by HEAD »

blanik wrote:the texture knob arrow is the other way, when maxed the wiper is connected to the .0047uF
Ok, that will be quick fix. I'll gonna correct it tomorrow as I'm running out of time now - have some BBQ to prepare.:)

Edit: I also might put the trannys the wrong way in. But for my personal use it doesn't matter as I'm going to use BC549C. And I'm used to always check the orientation of the trannys and never trust a diylc layout!:D
Last edited by HEAD on 21 Sep 2010, 15:59, edited 2 times in total.

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Post by phibes »

That kinda fuzz/gain control has been around forever ala the two knob Foxey Lady for example. I've messed around with it before and I didn't dig it too much. Makes for a fun Saturday on the breadboard though. It's kinda like you described, one side of the pot I'd have the good ol' horrible early Misfit's guitar tone (that ain't a bad thing!) and the other side was a od/fuzz boost. It's fun experimenting with different gain stages.
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blanik
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Post by blanik »

HEAD wrote:
blanik wrote:the texture knob arrow is the other way, when maxed the wiper is connected to the .0047uF
Ok, that will be quick fix. I'll gonna correct it tomorrow as I'm running out of time now - have some BBQ to prepare.:)

Edit: I also might put the trannys the wrong way in. But for my personal use it doesn't matter as I'm going to use BC549C. And I'm used to always check the orientation of the trannys and never trust a diylc layout!:D
both schem and vero are ok, the emitters all go to the cap/resistor to ground pairs and on the vero the orientation of the 2N2222A is correct according to the datasheet (TO-92)...

why the BC549C ? what could you expect soundwise? would they allow 18V? (since the Merkin is supposed to sound good on 18V (haven't tried it myself))

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Post by HEAD »

blanik wrote:
HEAD wrote:
blanik wrote:the texture knob arrow is the other way, when maxed the wiper is connected to the .0047uF
Ok, that will be quick fix. I'll gonna correct it tomorrow as I'm running out of time now - have some BBQ to prepare.:)

Edit: I also might put the trannys the wrong way in. But for my personal use it doesn't matter as I'm going to use BC549C. And I'm used to always check the orientation of the trannys and never trust a diylc layout!:D

why the BC549C ? what could you expect soundwise? would they allow 18V? (since the Merkin is supposed to sound good on 18V (haven't tried it myself))

Why? Simply because I have plenty of them at hand and I don't expect any noticable differences soundwise. 2N2222A are simple Si medium to high gain trannys as the BC549C also. That simple!;)

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Post by blanik »

HEAD wrote:
blanik wrote:
HEAD wrote:
blanik wrote:the texture knob arrow is the other way, when maxed the wiper is connected to the .0047uF
Ok, that will be quick fix. I'll gonna correct it tomorrow as I'm running out of time now - have some BBQ to prepare.:)

Edit: I also might put the trannys the wrong way in. But for my personal use it doesn't matter as I'm going to use BC549C. And I'm used to always check the orientation of the trannys and never trust a diylc layout!:D

why the BC549C ? what could you expect soundwise? would they allow 18V? (since the Merkin is supposed to sound good on 18V (haven't tried it myself))

Why? Simply because I have plenty of them at hand and I don't expect any noticable differences soundwise. 2N2222A are simple Si medium to high gain trannys as the BC549C also. That simple!;)

haha, ok i thought they where some kind of hi-fi version of the 2N2222 :oops:

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Post by roseblood11 »

@Helge: Kaffee, Kekse, BBQ... Machst du heute noch was anderes als essen? :D

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Post by HEAD »

roseblood11 wrote:@Helge: Kaffee, Kekse, BBQ... Machst du heute noch was anderes als essen? :D
Hihi, ja! Bier trinken! Hab die letzten Semesterferientage und die Sonne lacht, da kann man schon mal einen Tag so gestalten.;) Naja, und schließlich habe ich auch geroutet - und das nicht zuletzt nicht zu euren Schaden, oder?;) Das Merkin so so einfach aus, da war es mir ein Vergnügen. Hab so ne knappe 3/4h gebraucht dafür.
@ all: roseblood and I only did some off topic "kaffeeklatschi", to use this germanism.;)
I don't realy what to bash anybody at CB nor do I want to be a dick head. But man? A double layour pcb for that? :shock: This could be easily done even by me on a single sided pcb and it what even have or more "esthetic look" and I'm only a rookie with no electronical education background.

Helge

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Post by blanik »

HEAD wrote: I don't realy what to bash anybody at CB nor do I want to be a dick head. But man? A double layour pcb for that? :shock: This could be easily done even by me on a single sided pcb and it what even have or more "esthetic look" and I'm only a rookie with no electronical education background.
must be cheaper to use what they already have (materials and manufacturing process) than setting up single sided batches

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culturejam
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Post by culturejam »

What's wrong with a double-sided PCB? :scratch:

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Post by hbo »

I went over the screenshots and drew up a quick schematic. I got the same result as Salocin except the 47uF filter cap, and I have the Texture pot reversed. It looks to me the 2n2 cap goes to lug 1 of the Texture pot, not lug 3 (or I may be cross-eyed).

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Post by blanik »

hbo wrote:I went over the screenshots and drew up a quick schematic. I got the same result as Salocin except the 47uF filter cap, and I have the Texture pot reversed. It looks to me the 2n2 cap goes to lug 1 of the Texture pot, not lug 3 (or I may be cross-eyed).
you're right, i had the same results after checking it up (the schem, i haven't checked the vero), the filter cap and the reversed texture pot...

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Post by Hides-His-Eyes »

culturejam wrote:What's wrong with a double-sided PCB? :scratch:
Why, because every mass produced pedal should be a miniscule single sided PCB without any jumpers, of course! ;)

If they're already ordering square metres of double sided PCBs, I doubt they're any better off making one pedal single sided.
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