Check over Maestro FZ-1 Circuit

[robschmidt]

Hi all,


I'm about to start my first build after I've been experimenting with some parts. So I want to make a Maestro FZ-1 build following

this schematic provided by turretboard:

http://turretboard.knucklehead.dk/wp-content/uploads/2012/04/fuzztonefz1v1.pdf


Since I'm just a beginner with basic knowledge I'd like somebody to check the circuit before I start to solder everything.

I have some doubts about the correctness of the wiring but like I said...I'm just a beginner.

Thanks for your help!

[duck_arse]

welcome, rob.

no one has ever posted bad info on the interwebs, have they? many people will have built this circuit from this doc, but they may not see this thread. so, it might be more helpful to you if you tell where/why/what is causing your doubts, then someone expert can give you guidance and reason.

[robschmidt]

Thanks for the answer.


I assume the circuit board ist correct.

But what wonders me is the wiring of the switch and the potentiometers. It might be completely right but I'd like to sure before starting the build.

As a noob I can't point out anything specific.

[duck_arse]

ahh, I should point out that what you linked to was a layout, not a schematic. if we had the schematic used to produce that layout, we could then cross check. otherwise, we would just be assuming.

[mcknib]

Rob,

As a beginner I'd suggest there are far easier builds to start with this is a positive ground -3v circuit which even those of us that've built a few pedals sometimes struggle with.

There's an easier layout for vero here which also includes a small daughter board for the voltage inverter circuit that would allow you to use it with your normal negative ground pedals:

http://tagboardeffects.blogspot.co.uk/2014/08/maestro-fz-1-fuzz-tone.html

and some info here:

http://www.diystompboxes.com/smfforum/index.php?topic=94695.0

[robschmidt]

Thanks for your help and the links! I think the vero layout is for very helpful for understanding this.

Sorry for the question but what is the difficulty about a -3V positive ground circuit? Can't I just use a 2x1,5V Battery Box and connect the wires

as seen in the layout?

[mcknib]

Yes you can wire it as per the diagram but you couldn't daisy chain it with negative ground pedals which most modern ones are even using batteries the polarity of the circuit's reversed i.e your + is negative and your negative +

as I said not the easiest thing to wrap your head round or explain I think RG's idea to look at it as negative power supply is a better way to think of it

And negative power supplies don't play well with positive ones

[idy]

Yes you can use a battery like in the layout.

Positive ground is a little confusing because we are used to doing things the other way, and so our usual methods (red wire from battery to voltage, black to ground) don't work. Often we use black wire for ground inside a pedal and so it's a constant struggle against habits and intuition...

Secondly when you get to putting it in a box and putting that box on a  board with all your other pedals....you can't just "daisy chain" it to the rest as you will be shorting the power out! The simplest solution then is to use a voltage inverter. Or just a battery like you want to.

[robschmidt]

Thanks guys you helped a lot! I'm looking forward to the build!

[mcknib]

Idy's explanation is much better that's what I was trying to say anyway good luck with it and enjoy

[smallbearelec]

Hi--

I second what mcknib told you, and with emphasis: This is a horrible choice for a first build; there is way too much that you need to pay attention to concerning selecting transistors and proper biasing that the Vero diagram does not tell you. It's not that the author is looking to mislead; it's that he presumes that you are an experienced builder who knows certain ins-and-outs of working with leaky germanium transistors. Do Not attempt to commit this to solder until you can get it working on a breadboard. For information on how to select the transistors and line up the stages, see my article:

http://diy.smallbearelec.com/Projects/FuzzE-One/FuzzE-One.htm

I did it with NPN devices but 1.5 Volt supply like the FZ-1A. However, the idea is the same with PNP and 3 volts. I say again: If you want a better chance of success with your first pedal, pick a simpler, less finicky design! Even then, breadboard it first!  Happy construction!, and please hit Reply if you still have questions.

[robschmidt]

Thanks for the info.

I still think that I'm going to try it and just take my time with it.

I already have 3 transistors especially for a FZ-1 restauration with Q1 being a NKT275, Q2 being an AC128 and Q3 being an AC125. The gain

and leakage values should match the circuit. So is there anything special I should know about biasing the FZ-1?

[mcknib]

Steve's link provides some good general information obviously for an NPN version but can be used to get an understanding of the circuit.

So worthwhile having a read through the article and getting an understanding with regard to biasing
in the Tweaking it section.

[duck_arse]

if you search this forum for combinations of fz1, maestro, bias, leakage etc (I'm not saying it will be an easy search), you should turn up a number of threads containing info on gains and leaks and volts from real builds.