Build Your Own Clone Message Board

I've redrawn this for a possible short-run group buy. Anyone who is interested, please have a look at the original schematic I worked from to double-check my drawing:
http://analogguru.an.ohost.de/193/schem ... neFuzz.gif

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Function f(x)
TightCamera - Gear Reviews

Only comments are that the values of the pots and the trim doesn't match excactly, but that's no problem. And then the stupid question: That + in the circle in the left top corner, does that say that it is positive ground? (I'm used to reading other symbols for batteries, you see...) If it does, everything looks fine to me.

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Forwards in all directions!

I just assumed that nobody in the US would be able to easily source 47K and 2K2 trimmers/pots.


The + doesn't necessarily mean anything, it's just part of the symbol. The power supply is marked -9V to denote that it is a positive-ground circuit.

Of course, you could just as easily build it negative ground with different transistors and by swapping the polarity of the polarized caps. But I wanted to set it up true to the original.

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Function f(x)
TightCamera - Gear Reviews

Yes, I think that the BC549 in the npn equivalent for the BC559. Because of that, I will build two for myself (I have plenty of both transistors.). The third one goes to the other guitarist in my band, he claims that he DOES NOT LIKE FUZZ But now he WILL HAVE TO

BTW are you taking the time to breadboard this? And will you try to find out what gain range the transformers should have if it does matter with silicon? I guess it's not as critical as with a Germanium FF, but I am just a novice, especially with transistors, maybe one should need to match silicon transformers too? I read somewhere that Roger Mayer handpicked transistors for this circuit, but that's not nescesarily true, what do I know

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Forwards in all directions!

Lol now add a voltage inverter charge pump deal in there!!!

......im no help. I dont get schematics.

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The Dude abides.

No. The circuit works. There's no need to retest.


Nope.

Google the datasheet for the BC559 and see what gain it says. Then find an equivalent with the same gain. Or you could just buy them from Mouser. They are 7 cents each.

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Function f(x)
TightCamera - Gear Reviews

It looks correct to my inexperienced eyes.

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MIL-TDD-41

Looks good to me. Not sure if it was intentional or not, but the vol pot on the original is log, you have linear specified in yours.
What's up with the GND(T) coming off of Q1? Lookin at the layout in the other thread everything looks good (everything that needs to be is connected to the ground plane), so I'm just wondering.

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-Mike

Nothing. I just used the (T) varient there (it has a pad for the net) because I have to put it somewhere. I usually stick it up in the power section (like on the ground side of the power filter cap).

I'll change Volume pot taper on the schematic. Thanks for looking!

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Function f(x)
TightCamera - Gear Reviews

Cool, got it. Thanks for explaining that.

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-Mike

I'm putting the build guide here for safe keeping.

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Function f(x)
TightCamera - Gear Reviews

Feeling less surly my friend?

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http://srceffects.com/

Custom knob sets and effects. Free shipping in USA.

I just loaded my two up with 549c's and reversed polarity of anything that gives a damn. Hope to have one tested tonight.

update: Low, clean output. I am thinking I need to check orientation of the transistors.

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http://srceffects.com/

Custom knob sets and effects. Free shipping in USA.

I got clean output when I had the in/out jacks grounded to DC ground instead of +9v.

Also make sure you reverse the +9v / GND connections on the PCB (error, per the build guide).

Also BC549 is NPN. You want BC559, which is PNP.

I tested with 2N5087. 2N3906 should also work.

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Function f(x)
TightCamera - Gear Reviews

I am trying for npn, rev'd the electros. That makes the board markings for ground and voltage correct.

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http://srceffects.com/

Custom knob sets and effects. Free shipping in USA.

Hmmm. Well, it sounds like you have everything right. But something obviously is amiss. You didn't also reverse the pinout of the transistors right? That ought to stay the same, I believe.

I really hate dealing with PNP/NPN conversions. I get confused every time.

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Function f(x)
TightCamera - Gear Reviews

I dropped them in the same as the shape printed on the board but I didn't check pinout at all. I yanked them this morning and put in sockets but hadn't gotten any farther. I figure a few other guys are going to go NPN so I'll keep you posted.

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http://srceffects.com/

Custom knob sets and effects. Free shipping in USA.

Actually, yeah. Double check the pinout for BC549. It might reverse of the "standard".

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Function f(x)
TightCamera - Gear Reviews

I tried some of the ole reliable 5088's and she sounds amazing.

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http://srceffects.com/

Custom knob sets and effects. Free shipping in USA.

Nice!

If you're up for it, you could write up "Sean's Awesome Guide to NPN Usage in the Stein Fuzz".

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Function f(x)
TightCamera - Gear Reviews

I am still playing with it, going to try a few diff transistors including a few mojo laden varieties to see what sounds best to my ears. I'll def report back.

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http://srceffects.com/

Custom knob sets and effects. Free shipping in USA.

I'm very interested in hearing about any discovery you make here. Especially what hfe values you put in there and how it turns out with higher gain values if you break the "rules" for a traditional fuzz face.

I will build mine probably after Easter, it's just too much to do right now, and I haven't even stocked up for this, except for a new soldering station.

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Forwards in all directions!

Here is what I've found and the transistors tested:
2n5088's, Hfe's around mid 400's
Mpsa06 Hfe around 180
2n3904 HFE around 215
MPsa18 hfe around 1150
MPSA13 hfe around 42k

The 2n5088's, MPsa06's, N23904's all biased easily and had low noise, same tonal character IMO.
The Mpsa18 was easy to bias and same tonal character but noisy.
The MPSA13's sound more like a Shin Ei and are not so easy to bias, but there are lots of oddball tones along the travel of the bias pot. Kind of noisy.

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http://srceffects.com/

Custom knob sets and effects. Free shipping in USA.

I can't believe I don't know the answer to this question without asking, but this is something I would never consider on a pedal… If I wire this up so it can only be powered by a battery (to avoid some dumbass by which I mean me of course plugging it in with the rest of the chain), where do the wires of the battery snap go?

I assume the black one can go to any ground point in the circuit, and the red one is soldered to the 9V spot on the PCB? Again, this seems like it should be obvious, but I want to make sure so I don't fry anything. This is the problem with being a solder-by-number hack.

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Scott

My band, Austin Hollow

If you wire the red lead straight to the board, the battery will always be in the circuit (ie - it will be pulling current all the time). You want to wire it first to a stereo jack (input jack, usually), and then on to the board. This will kill the circuit when the input jack is removed.

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Function f(x)
TightCamera - Gear Reviews