maestro fz1-b info

[pinkjimiphoton]

hi guys,
got my friend glen's fz1b, it appears to be the model with the "squelch" control...
due to the fragile condition (it's deteriorating inside, i don't wanna break it) i didn't take it apart,
tried to take some pics but couldn't get anything even close enough to be worth posting...no zoom function on my camera,
and the phone shots are worse.

but.. i did manage with my jeweler's loupe  to read the trannys, which appear to be labeled 2298n.

without taking it apart, i couldn't really be sure which legs are which on the three trannies, but they all read 2298n

i THINK i got this right... i believe the transistors are e c b rather than ebc...caveats apply that i may have this wrong, the schematic inside isn't much help
with the pinout.

but this is what i got

q1
e 7,87
c 9.15
b 8.04

q2
e 0
c .84
b .53

q3
e 0
c .49
b .47

this would be looking at the schem with q1 left, q2 right, and q3 center.

hope it comes in helpful to someone.

peace

[LucifersTrip]

thanx for posting....though, I'm a bit confused.

I saved a few versions of the FZ-1B schematic. One has 2 transistors:
http://www.guitarpedalseffects.com/Maestro_Fz_1s_Fuzz.jpg
http://analogguru.an.ohost.de/001/schematics/Maestro_FZ-1B-v1.gif

and the one with the squelcher has 4:

[680K & 3.3M reversed on some schematics)

so,you posted the voltages of the 3 minus the squelcher, you reversed q2 and q3 on the schematic ("q1 left, q2 right, and q3 center") and how is it possible q2e and q3e both be 0?

the unit you are measuring sounds cool?

thanx again for taking the time to measure em

[pinkjimiphoton]

that's the schematic inside the bottom of the unit.
but there's only 3 transistors in it!
the thing sounds great, real fuzzy in a good way, not subtle.
i will ask glenn (who i returned it to last nite) if i can borrow again and if this time i can have permission to disassemble it ...
i had to kinda try and guess at which legs of the trannys were which cuz it's deteriorating some inside, and he asked me not to mess with it too much.
all the caps were ceramic, except for one bumblebee, also.

the voltages were recorded originally with the flat part of the trannys facing me,
left-right

7.87
9.15
8.04

0.0
.84
.53

0.0
.49
.47

sounds like a very classic old fuzz, tho kinda sputtery...could probably be cleaned up some, but he doesn't wanna add/change anything at all in it.

when i see him next week i'll see if i can borrow it again, and try and get permission to open it up and disassemble it enough to be more definitive.

the voltages seemed a little "off" to me, too..

it looks like THIS one had everything BUT the squelcher... absolutely 3 transistors. unless i am blinder than i thought.

EDIT: here's the better of the pics i tried to take...they pretty much suck, tho..

[joegagan]

the board looks identical to this


i think what you have here is a 4 trans.
if you can look at the underside, it might look like this (same pedal as above)

[pinkjimiphoton]

unless i was ridiculously stoned when i had this thing open, which of course is possible, this one has only 3 transistors.
and it doesn't say cmi on it, it says gibson inc....again, i didn't actually pull it apart, just peeked inside.

here's a couple other pics




here;s a shot of the gut, it's a terrible pic, but i've circled the three transistors. i didn't see a fourth.
i'll facebook glenn tomorrow, see if i can get it back over here.



i don't believe there is a 4th transistor, i don't see how i could have missed it.....but it's possible. i guess...

joe, i know the pics suck, but look closely at the board you posted and the one i did. they are NOT the same.

again, i could be wrong, but....

[joegagan]

hi jimi, please tell me what differs. i did not see a single difference.
since you were instructed not too disturb things, it is quite possible you could not see the 4th transistor. it would be tucked under that ceramic cap near the bottom of the board.
the exterior of the unit i photographed/restored/videod is identical to your photo as well.

[joegagan]

and yes, your pics DO suck

[Mark Hammer]

I'll once again openly confess my lack of knowledge about transistor circuits.  So this is a shot in the dark.

I'm wondering whether the squelch function (using the schematic that lucifer's trip posted) operates by D1 forming a simple rectifier that feeds the base of Q4 so that Q3 forms either a high or low resistance path to ground for the emitter of Q4, depending on signal strength.

Have I got that part right?  And if I have, would that mean that the unit CAN function with 3 transistors if one omits D1 and all that other stuff south of Q4 and just connects Q4's emitter to ground?  Or would the unit simply be too noisy (hence why Maestro included the squelch)?

Alternatively, could a pot adjustment of one or both of the resistances feeding Q3's base serve to make the squelch function more "glitchy" for those who like that sort of thing?

Just curious.

[joegagan]

i have heard of 2 trans ( seen pics of board, totally different ), 3 trans and 4 trans versions of this iteration. it is not unfathomable that maestro skipped the 4th trans and built some with the same board and 3 transistors.

have not seen a schem for a 3 trans version tho. since maestro in this era was pretty religious on providing printed schems inside the peds, why does no one have a factory 3 trans schem?

[Mark Hammer]

For reasons I don't quite understand, Maestro factory schems can be iffy (note the comment in the post with the schems about where the 680k and 3M3 go).  At least the ones we collectively have access to.

But you're right that, unlike many of their competitors (Shin-Ei being a noteworthy exception), they put schems inside their pedals.  It makes no sense that they would deliberately put erroneous schems in there (the precursor to gooping?  I think not  ), so I'm more likely to just chalk it up to poor quality control.  But yeah, how come no other versions have surfaced by now if Maestro was so free with their technical info?

Incidentally, just to avoid any unintended suggestion that 3-transistor versions exist, I meant to imply that maybe those wishing to make a clone might be able to successfully do so without the circuitry around Q3.

[joegagan]

gibson absolutely would not have intentionally put erroneous info on their schems during this era. it would have led to much larger problems, they needed the repair community to have tools to prevent returns to the mfgr.

the errors we have seen are usually one  r value, nothing too serious.

the mention of 3 trans FZ1 B are on the net, prior to this thread. i have not seen any evidence other than these mentions.

[pinkjimiphoton]

joe, like i said, you're probably right.

i thought it was a two transistor until i found the third one lurking under the ceramics. good call. but here's the thing... i didn't disassemble the unit, but i DID
push caps out of the way so i could see the numbers on the trannys... like i said, i will contact glenn and ask to borrow it again next week (and maybe build him a fuzzface for his trouble
as our thanks for allowing it's disassembly).

but... it's a sputtery beast and tho it sounds good, it's more like a misbehaving ge fuzz sound than a more sustainy bmp or tonebender kind of sound.

maybe mark's right?

maybe you're right?

maybe it's some weird ass oddball..i do notice it had a single what i took to be a bumblebee cap...like, a black plastic liooking tube with colored rings on it.

so....if it's  4 transistor, i'll take the egg on the face. won't be the first time, won't be the last.

but if it's a 3 transistor, than mebbe they DO exist.

sending glen an email now. stay tuned guys.

ps...next round of photos i'll do with my phone instead. the dig camera i have is no good on anything closeup, sorry.

[pinkjimiphoton]

gibson absolutely would not have intentionally put erroneous info on their schems during this era. it would have led to much larger problems, they needed the repair community to have tools to prevent returns to the mfgr.

the errors we have seen are usually one  r value, nothing too serious.

the mention of 3 trans FZ1 B are on the net, prior to this thread. i have not seen any evidence other than these mentions.

gibson couldn't even keep it's guitar serial numbers together during this period....just sayin'...

[Mark Hammer]

gibson absolutely would not have intentionally put erroneous info on their schems during this era. it would have led to much larger problems, they needed the repair community to have tools to prevent returns to the mfgr.

Absolutely.

the errors we have seen are usually one  r value, nothing too serious.

Especially when you consider that these were pasted to the inside of the chassis at a time when no one would have even begun to think of using the information for cloning or competitive design.  In other words, if you were a repairman using the schematic to fix one (in between TVs and stereos), you could easily excuse the error on the drawing because, after all, you had a "real one" in front of you.  "Repairs" might be re-attaching wires that had fractured during battery changes or by virtue of jacks coming loose and rotating too much, bad pots, or maybe blown transistors.  All of those repairs would not likely be derailed by a few mislabelled components.  And of course, there was no requirement to be absolutely explicit about transistors because - again - as a repairman you had the darn part in front of you and could see what it was so you could look up the number of a replacement part in your HEP, RCA, or Allied/Radio Shack catalogue.  (hmmmm, just when did NTE/ECG come into existence?)

Jimi,
If it has three leads, there's apretty strong likelihood its not a capacitor.

[joegagan]

i had a similar misconception. a few days after i sent the above unit back the customer, i could not find the diode that the schem listed in my photos. other people posted photos , other  FZ1-Bs where the  caps were bent out of the way , showing the diode under the sea of caps.

[pinkjimiphoton]

mark and joe, the thing i saw is absolutely not a transistor. it's a black tubular cap, two leads, and a cap style color code on it.
i just wrote glenn, and asked for him to give me permission to actually take it apart at least enough to see the bottom of the circuit board.

worst case, if i don't catch up with him over the weekend, i will see him at the jam i host on tuesdays. he only lives about a mile away.

if it DOES only have the three transistors, then that would tend to indicate there IS a 3 tranny version... cuz i've heard the two and 4 tranny versions...
to my ear,  the 4 tranny is slightly smoother and the 2 transistor more fuzzfacelike. this is very raspy, broken sounding fuzz...very cool for what it is, but not
an every day, go-to fuzz.

i've seen a lot of schematics where things are wrong...the schem of the ludwig phase II comes to mind, where there are blatant ommissions and absolutley wrong values on the schem
when compared to dino's and my original units.

like mark said, they were provided as a convenience...but back in the day, techs were mostly propellorheads, and they didn't necessarily even need the schematics.

no use monday morning quarterbacking this, as soon as i hear from glennjamin  i'll post here.

[Mark Hammer]

Again, just out of curiosity, are there any signs on the board that it may have accommodated other components?  For instance, are there holes visible?

I ask because, as you've probably encountered too, you can often find boards with unused pads.  The manufacturer may have come to realize that some issue they were trying to prevent did not need such a heavy-handed solution, or was perhaps less problematic than first thought, so the parts are omitted, the money and labour is saved, and the batch of boards they had made back when they thought they needed that fix...get used, with spaces left.

So, if you were Maestro, and you had all those boxes made, and the stickers with the schematic, and the boards, but then you thought "Meh, the 4th transistor is really more trouble than its worth", would you produce pedals that had the 4-transistor schematic glued to the inside, but ony 3 transistors on a board made for 4?

I'm not saying that's what happened here.  I'm just riffing on other possibilities that are within the perimeter of reality, such as we know it.

And yeah, there have been some weird-ass caps made over the years.  I bought an old Heathkit TA-17 last week, and the power supply cap looks like it was taken from an uninterruptible power supply for a 1970's mainframe; about 5" across the top.  When I replace it, I don't know how the heck I'm going to secure the new one, because its about 1/50th the size.

[pinkjimiphoton]

if ya look at my crummy pics, you can see there are indeed a couple holes in the pcb where nothing was mounted.

i believe the weird cap i describe is a sprague "black beauty" if i recall from my ancient collections of electronics mazagines.

these days, people call them bumblebees, and pay big bucks for them, thinking there's mojo in them. there isn't.
but they LOOK cool.

[Electron Tornado]

Not sure if this has been discussed before elsewhere, but looking at the schematics I have a couple of questions.

1. What is D1 doing without the squelcher circuit? Clipping half of the wave form?

2. Actually, I don't know what it does with the squelcher circuit, or what the squelcher circuit does, either.  

A few minutes later....

Well, after taking a look at it, does D1 change the base voltage on Q4 during one half of the wave cycle as some strange means of creating asymmetric clipping?

3. Looking at this schematic: http://www.guitarpedalseffects.com/Maestro_Fz_1s_Fuzz.jpg it looks like the output from Q1 at C3 is connected to V+. Why would it be connected to V+, or is that a mistake?

4. In this schematic again: http://www.guitarpedalseffects.com/Maestro_Fz_1s_Fuzz.jpg   Very strange way to do the bypass. Keep the signal that passed through the buffer and simply shunt the effect signal to ground. Strange. I wonder if some bean counter decided that a SPST switch was cheaper that a SPDT or DPDT.

[Mark Hammer]

if ya look at my crummy pics, you can see there are indeed a couple holes in the pcb where nothing was mounted.

I can look all I want, but while I'm at work, I can't see.     I'll look AND see when I get home.

Hmm, so maybe what I suggested is a possibility?