freestompboxes.org

Maestro FZ-1S guts:

http://i1.ebayimg.com/07/i/000/db/2f/7de4_1.JPG
http://i5.ebayimg.com/04/i/000/db/2f/80ae_1.JPG

analogguru

Here's mine. I uploaded these to my photobucket account earlier this year and forgot about it:















Been a while since I plugged this in, need to dig it out and fire it up!

Very interesting:

The factory schematic I have states for Q1 = 2N 3391 and Q2 = 2N 3392.
Your schematic says for Q1 = BC 109C and for Q2 = 8393.
Inside your unit are for Q1 = 2N 5088 and for Q2 = 2N 5133.
For Q2 the transistors need only to be any junk, cause they are used as diodes.
So you can replace them with any transistor and sell the 2N 5133 for big money to a Big-Muff-addict.

BTW, whats up with the german warsteiner beer which can be seen in the third picture ?

analogguru

analogguru wrote:Very interesting:

The factory schematic I have states for Q1 = 2N 3391 and Q2 = 2N 3392.
Your schematic says for Q1 = BC 109C and for Q2 = 8393.
Inside your unit are for Q1 = 2N 5088 and for Q2 = 2N 5133.

Yeah, I have a couple Maestros that have different schematics vs the actual guts. I've got two FZ-1B's which neither match the case schematic.

So I'm assuming from my limited understanding of circuits that the two pairs of trannies are per fuzz channel, right. FZ-1B had three, so why the step backwards on this circuit? I haven't played through this thing in a minute, but I don't remember it being an especially powerful fuzz, my working FZ-1B is much stronger. Did Oberhiem design the FZ-1B as well?

analogguru wrote:For Q2 the transistors need only to be any junk, cause they are used as diodes.
So you can replace them with any transistor and sell the 2N 5133 for big money to a Big-Muff-addict.

Hah! I know a couple Muff Addicts, I've only got like 5 of them myself, hardly a collection.

analogguru wrote:BTW, whats up with the german warsteiner beer which can be seen in the third picture ?

That particular one? I drank it at least 9 months ago. Many others have come after it.

Sickle wrote:So I'm assuming from my limited understanding of circuits that the two pairs of trannies are per fuzz channel, right.

wrong... there is only one Fuzz-channel with a tone-switch like on an Ibanez Standard Fuzz, Fender Blender or similar units.
The circuit topology could be best understood as an Mxr-Distortion+ with a tone switch and a blend-control like on a Klon Centaur or Maxon OD-820.

Circuit description of the FZ-1S:
The upper left transistor is only an input buffer without any gain.
Then the signal is split and in the upper row the vlean signal feeded to a mixer/amplifier stage via one half of the balance pot.
The second path goes to the lower row. after the sustain potentiometer we havew a 2-stage high gain amplifier (like in an Mxr Distortion+ or Proco Rat).
The output of this amplifier is applied to a diode-clipper formed by the two transistors marked as Q2.
The Fuzz switch only selects between filtered and unfiltered nothing more - it´s a tone selector.
With the second half of the balance pot you control the volume of the distorted signal. Since this is a stereo-poti which works in opposite to the other half in the upper row when you move this poti to the left, more clean (and less distorted) signal is send to the mixer-amplifier and when you move to the right, less clean signal and more distorted signal is send to the mixer-amplifier.
The mixer-amplifier at the right upper row is there to compensate the signal loss of the balance-control.

FZ-1B had three, so why the step backwards on this circuit? I haven't played through this thing in a minute, but I don't remember it being an especially powerful fuzz, my working FZ-1B is much stronger.

It´s a complete different approach for a distorted signal. As I said, more like a Distortion+ with blend control.

Did Oberheim design the FZ-1B as well?

I highly doubt that Oberheim designed either the FZ-1B or the FZ-1S.
Oberhaim stuff always used epoxy-pcb and different resistors.
Maybe it was made by ATD (All-Test Devices Corp.) who built at least the Boomerang, the Octave Box and the Signal Isolators.

analogguru wrote:BTW, whats up with the german warsteiner beer which can be seen in the third picture ?

That particular one? I drank it at least 9 months ago. Many others have come after it.

"Georgia on my mind".....you really need german beer ? Don´t they have drinkable beer in "sweet home alabama" ?

analogguru

analogguru wrote:

Sickle wrote:So I'm assuming from my limited understanding of circuits that the two pairs of trannies are per fuzz channel, right.

Circuit description of the FZ-1S:

Cheers for that detailed explanation, it was a big help. I've had a slow, choppy progression learning hardware circuits. I think at least a part of the problem is I've used Reaktor for the last 5 years and I 'think' my circuits in Reaktor, so looking at a circuit I frequently find myself easily lost, which has been really frustrating. I'd really like to understand what's going on in hardware circuits on a much deeper level, but its taking me a lot longer than I thought it would. I'd like to be able to look at something and say, 'ok, this resistor is affecting the tone this way, that cap is doing this over here, etc'.

Slow going so far, but time works against me a lot.

analogguru wrote:you really need german beer ? Don´t they have drinkable beer in "sweet home alabama" ?

I sold one of these a few years ago....found it at a rummage sale for $5...couldn't find a decent sound in it.... got $180 for it......

8^)

ps I'm not hating exactly.....i'm just not a fuzz type of guy....having 0 experience with fuzzes made me wonder if it was just me or if that particular fuzz just ain't much good.....

wader2k wrote:I sold one of these a few years ago....found it at a rummage sale for $5...couldn't find a decent sound in it.... got $180 for it......

Couldn't find a decent sound in it? Maybe you should have tried this one instead.

marshmellow wrote:

wader2k wrote:I sold one of these a few years ago....found it at a rummage sale for $5...couldn't find a decent sound in it.... got $180 for it......

Couldn't find a decent sound in it? Maybe you should have tried this one instead.

I figured on catching flack for that......but really it was just too gated and finicky.... not my thing......

Can anyone see anything in that schematic that would lead to me getting only 1.4k across one half of the balance pot or does it sound like something's dodgy?

Hides-His-Eyes wrote:Can anyone see anything in that schematic that would lead to me getting only 1.4k across one half of the balance pot or does it sound like something's dodgy?

Not really following you. The balance pot is a 30k dual. You are reading 1.4k where?

Reading 1.4k across the "dry" half of my balance pot and wondering if I've fried it. (as in 1.4k between lugs 1 and 3)

hey y'all

i have a few questions about these schematics.
i read somewhere that the factory schematics had mistakes in them, like for the BB-1 brassmaster. are these correct?
and since 2N5133 are just used as clipping diodes, can they be replaced by any silicon transistor or do they have a specific Vce that can't be matched with any other silicon transistor? will 2N5088/9s do the trick?

thanks

I am going to build a clone and use BC109Cs. What gain would you recommend please?

Frances Rhodes wrote:hey y'all

i have a few questions about these schematics.
i read somewhere that the factory schematics had mistakes in them, like for the BB-1 brassmaster. are these correct?
and since 2N5133 are just used as clipping diodes, can they be replaced by any silicon transistor or do they have a specific Vce that can't be matched with any other silicon transistor? will 2N5088/9s do the trick?

thanks

It shouldn't make any difference so you can replace them with any silicon transistor and it should work fine....

Yazoo55 wrote:I am going to build a clone and use BC109Cs. What gain would you recommend please?

BC109C transistors typically have an Hfe (gain) of about 480 so they should have plenty of gain, you could even use BC549C transistors which are basically the plastic encapsulation equivalent of the BC109C, but they are low-noise types, they have Hfes (gain) as high as 860....

Long time no see fuzz freaks
Here is FZ1S trace based on vintage unit owned by Arcane Analog (big thanks men!).
PCB trace to follow.

PCB size is 92x46mm.

some gut shots!