Maestro Fuzz Tone FZ-1B

[warioblast]

Hi,
I believe this schematic is wrong (so is the FZ1S one)  http://geocities.com/teleman28056/pictures/Maestro_FZ-1A-1B-1S_fuzzes.pdf
Does anybody have the correct one, or at least tell me what's wrong with the above schematic. I know some of you guys own the original pedal, I just hope you'll chime in.
Cheers,
Fabrice

[Mark Hammer]

Here's what I can see that is wrong:

1) The FZ-1B shows C3 connected to V+.  That's plum crazy.  The signal should go from C3 only to the junction of R9 and the volume pot.  This circuit is actually a sort of interesting variant of the Shin-Ei and Fuzz-Rite circuit in that is uses two fixed gain stages in series and allows the user to adjust how much of the feed it takes from the first vs the second (more distorted) stage.  The FZ-1B adds a single clipping diode into the mix which is sort of interesting.  Makes me kind of wonder how this compares to the Harmonic Percolator.

2) The FZ-1A looks fine.

3) The FZ-1S schematic is messed up in several places.  R14/R9/R5 are supposed to be tied to V+, not the wiper of the Balance control.  Conversely, why the heck is R7 skirting around the rest of the diagram and then connecting to V+?   That resistor is the one that should go to the wiper of the lower half of the balance control.  That balance control is a reverse-wired mixer knob that feeds the upper right "Q1", which is a mixer stage.  In one direction you get less of the fuzzed signal and more of the clean signal from the input stage.  In the other direction you get more of the fuzzed signal and less of the clean input.  I inheritted an original one of these and it has a nice sound.  Can't vouch for either of the other two.

[brett]

Hi
That schematic is quite odd.  If you're aim is to get that tone and not to build an FZ-1B specifically, you might consider building a Fuzzrite.  It has that trebly 1960s fuzz sound like the FZ-1A that you hear on "Satisfaction", but uses easy-to-get Si transistors, and doesn't have the bias and noise issues of an FZ-1A.
cheers

[warioblast]

brett
I have already built the fuzzrite 
http://www.diystompboxes.com/smfforum/index.php?topic=46573.0

Mark
Yeah that C3 connected to V+ totally killed the signal.
Once C3 is going to R9 & the volume pot, the sound of the pedal is more like a treble booster, with low ouput, unusable with a clean channel, but makes a nice boost to the dirt channel of my Marshall.
I also tried to connect the Connector of Q1 with the Base of Q2, breaking the connection between Q1s Emitter with R4 & C2. With C3, R4 & R5 removed, and only C2 connected between Q1 C et Q2 B, I had a fuzz sound, closer to "satisfaction" than my fuzzrite. But I'm just playing with the breadboard, swapping parts and wires, and unless Sir HC or any Fuzztone owners come in, I'm stuck 

[Sir H C]

That is the rarer version (as far as I can tell) of the FZ-1B.  Most that you see are a 4 transistor arrangement with squelch and the like.  A lot of these Maestro schematics seem to have errors in the supply rails.  I have wondered if it was scanning a long time back that someone then tried to "correct" or if they just flubbed it from the start.

Oh and the picture on the FZ-1A page is the FZ-1S.

What is misisng is the other schematic for the FZ-1B which is really cool sounding, it is very gated as it has a gate in circuit (squelch control).

[Mark Hammer]

Rick Lawrence send me a wad of Maestro schematics, or rather, photocopied service manuals a while ago.  There were a number of errors in these "factory supplied" schematics.

[Sir H C]

And not too many of my favorite thing in some Maestro schematics, very warped notes.

[Mark Hammer]

Listened to the Fuzz-Rite sample that Warioblast posted.  Great choice of material!!

[Mark Hammer]

Found a bit of time and perfed the FZ-1B, as per this "corrected" (at least according to my intuition) schematic: http://img.photobucket.com/albums/v474/mhammer/FZ-1B.png

It "works", and there is a wee bit of grit audible when I turn the Balance pot up all the way, use the neck pickup and slam a chord, but nothing you'd call a fuzz.

So, we have two successful builds that confirm something is amiss with this schematic, as shown.  Is it possible that R8 should be something different than 22k?  Or is there some other component misprint that would (if correct) produce more gain?

[Dragonfly]

Found a bit of time and perfed the FZ-1B, as per this "corrected" (at least according to my intuition) schematic: http://img.photobucket.com/albums/v474/mhammer/FZ-1B.png

It "works", and there is a wee bit of grit audible when I turn the Balance pot up all the way, use the neck pickup and slam a chord, but nothing you'd call a fuzz.

So, we have two successful builds that confirm something is amiss with this schematic, as shown.  Is it possible that R8 should be something different than 22k?  Or is there some other component misprint that would (if correct) produce more gain?

you might try a 2k2 at R6 and R8.

is c2 really a 47u...or should it be 4u7 ?

r9 could be smaller if output is low

also, a 2n3392 was IIRC, a pretty high gain silicon...if you didnt already, you might try 2n5088 or 2n5089's in there.

just some thoughts

AC

[Sir H C]

Is a picture of the board from one of these fuzzes.  I can try for better ones (these are off the E-bay auction), but you can't really open it up fully.

It doesn't have much in the way of buzz though.

[Mark Hammer]

The measured hfe on the pair of 2N3392 transistors I had left was in the 160-170 range, so not what you'd call high gain.  Perhaps something with a little more zip could be inserted for the Q2 position.

[PRR]

Dissection of Maestro Fuzz Tone FZ1B (4 transistor w/squelcher)

http://www.el34world.com/Forum/index.php?topic=11230.0

[LucifersTrip]

That's killer...nice to see it in it's original ragged glory...

Did anyone ever figure out what the 991-002298's were...or what the ballpark hfe's/leakages for this one were?