Maestro - FZ-1  [schematic]

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Re: Maestro - FZ-1

Postby lowbrow » 21 Dec 2012, 19:08

There is a lot of information on "optimal" voltages for the FZ-1a, but none on the FZ-1. Now, I figure its pretty straight forward to extrapolate from Small Bears notes on the 1a to arrive at voltage ranges for Q1 base and Q3 collector, but Q2 collector doesn't really fit this method.

I've spent a lot of time on the breadboard with this one tuning by ear and arrived at what I thought was a pretty optimal range for Q2 collector. But then I got curious if it could be calculated as well. Working backwards from the FZ-1a voltages, and knowing we are dealing with a 10k collector resistor, we know that roughly 125microAmps are flowing to the collector.

If we assume we want this current to be flowing into the FZ-1 collector (good assumption or bad?), and knowing its collector resistor is 1K5, we should see around 2.85 volts on the collector. Is this sound analysis anyone? Am I making some incorrect leaps of logic here? Coincidence or not, I found it interesting,if not gratifying, that my ear experiments lead to similar results.

So, does anyone out there have some hard data on this? Maybe measurements from a original pedal?
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Re: Maestro - FZ-1

Postby LucifersTrip » 21 Dec 2012, 23:18

lowbrow wrote:
If we assume we want this current to be flowing into the FZ-1 collector (good assumption or bad?), and knowing its collector resistor is 1K5, we should see around 2.85 volts on the collector. Is this sound analysis anyone? Am I making some incorrect leaps of logic here? Coincidence or not, I found it interesting,if not gratifying, that my ear experiments lead to similar results.

So, does anyone out there have some hard data on this? Maybe measurements from a original pedal?


I'm not sure if you can make that assumption since different transistors were used in the 1 and 1A. It's possible the 1.5K was changed to 10K because their stock of 2N2613's had different specs (higher or lower leakage) than the 2N270's....or they were altering the bias for an "improvement"
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Re: Maestro - FZ-1

Postby lowbrow » 22 Dec 2012, 00:23

Precisely. I don't understand just enough about this yet to make a truly informed guess. I've got actual 2N270s and 2N2613s to work with here. I can say the 2613s are much higher gain, leak less in general and are less temperature sensitive. They also spec out having better frequency response, which I suspect is part of the reason the FZ-1 sounds the way it did. 2N270s only had 400kHz frequency response. Less than half of most transistors.
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Re: Maestro - FZ-1

Postby lowbrow » 22 Dec 2012, 00:53

I meant to also say...I'm not sure the different transistor argument is valid though...mostly because it was argued by Small Bear and his brothers in research on this that model and gain of transistors mattered much less than leakage to the design. Now, they where speaking of the 1a, but I have to think its doubly true for the 1.
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Re: Maestro - FZ-1

Postby LucifersTrip » 23 Dec 2012, 03:29

The model of transistor doesn't matter. It is the leakage that matters. But that's a completely different idea than what I stated above.

If they knew one model transistor generally leaked more than the other, they would alter the biasing resistors to match the different transistor....that's if they were shooting for the same voltages...or relative voltages.

They did that with the TB MKII when transistors were changed in different models.
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Re: Maestro - FZ-1

Postby lowbrow » 23 Dec 2012, 13:54

So you're implying that the voltage on Q2 collector should be, more or less, twice that of what is optimal for a -1a?

I find it a little odd that, given the historical significance of this circuit, that there is so little analysis or information on it. The -1a is certainly covered well, but it was not the FIRST fuzz pedal. The one that inspired so many to come.
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Re: Maestro - FZ-1

Postby LucifersTrip » 23 Dec 2012, 22:12

lowbrow wrote:So you're implying that the voltage on Q2 collector should be, more or less, twice that of what is optimal for a -1a?


only if they were shooting for the same relative voltages...and remember, the fuzz pot biases Q2
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Re: Maestro - FZ-1

Postby lowbrow » 16 May 2013, 17:35

I've spent a great deal more time with the Fz-1 circuit since my last round of posts and have arrived at a place I'm pretty happy with sound wise, so I thought I'd share my conclusions here. Before I do, I'd like to state that my knowledge has not gotten to the point where I can mathematically explain most of this, or do a proper engineering circuit analysis (like a loop analysis?), so if anyone can shed some light from that aspect, please do as I am eager to understand as fully as I can.

There are a lot of places and layouts out there that advocate using a trimmer on the collector of Q2 with various arguments as to why. In my opinion, after much experimenting, this is a rabbit hole to stay away from. In short, it is possible to get decent sound using this method, but you more often than not end up with a pedal that is not as loud as it can be and a Attack knob that has extremely limited functionality.

I eventually came to the conclusion the best place to instal the trimmer is between the -3 volt rail and the base of Q2 or, put another way, in place of the 470K resistor. I have yet to find a instance where a 500K trimmer is not sufficiently large for the job.

A little about Q1 and Q3…all pretty much garnered from SmallBear's article on the Fz-1a and my own experiments.

Q1 is a emitter follower and therefor a input buffer and impedance matching device. Great little website that explains some of this:

http://hyperphysics.phy-astr.gsu.edu/hb ... cc.html#c2

The upshot of all the technical info is this…you want as close to 1 volt on the emitter of Q1 as you can get. You might be able to achieve over 1 volt, I have had some transistor selections that hit almost 1.4 volts, but the range you're really looking for is between 0.8 volts and 1.2 volt. Less than this and the current flowing into the base of Q2 is too small, more than this and you start to introduce a lot of highs that you really don't want in the sound. I have found, given the range of around 0.8 volts to 1.2 volt on the emitter, it's pretty easy to select a transistor to hit the marks and just stick with the stock resistor values in this stage. Someplace in the 60-80 gain range with around 150µA leakage (that's microamps in case in my little mu symbol doesn't translate on your machine). That's more a minimum leakage guideline…but too much over that and you might start introducing hiss and other white noise, so watch out. There is no real benefit to going over 60 on the gain in my experiments, BTW.

Q3 is, mostly, there to amplify. It can and does add to the sound and there is some distortion introduced there depending how you set it up, but it is not the major contributor to the fuzz effect. To get this stage to work you have to have leakage. It's way more important than gain. My preference is to find a transistor that has a good amount of both, however. I like to try to use something with at or over 100 Hfe and about 250µA of leakage. It's not necessary to mess with the original resistor values in this part of the circuit either, stick with the stock values and just try different transistors till you get about 2.5 to 2.7 volts on the collector (my personal preference and measured with attack on maximum). You can also go down to around 80Hfe, but I think they sound best with someplace around 100. It's the leakage that turns this on and starts to drop the collector voltage where you want it. Remember…as the collector comes down in voltage from the power rail, the amount of current flowing increases….you want to have a good amount of current flowing, but not necessarily the maximum amount that could flow. The reason is, if you keep it near saturation (which would be a collector voltage of 3 volts as I understand it, or equal to your power source), you get some cool clipping in the signal that adds nicely to the overall fuzz sound. Or, so my technically challenged brain seems to think. Am I wrong in this understanding? It sure does seem like what my ears hear.

OK, so that leaves Q2 and this is where the magic happens. Once I got away from trying to set this stage up by adjusting the 1K5 collector resistor, I started to get results I really liked. As stated, I prefer to use a 500K trimmer in place of the 470K from the power rail to the base. All other values in this stage stay stock. I have found that if I use a transistor that has right about 200µA of leakage and a gain around 90 or so (think 85-90 Hfe on up) I can get some kick ass sounds and sounds that match many of the known Fz-1 recordings out there. How I bis it is pretty simple too. I set the Attack pot on MAXIMUM and adjust the trimmer till I'm getting slightly over 0.2 Volts...try for less than 0.4 Volts on the collector, but it will be touchy and kind of difficult. When you do this, you should see in the area of 2.7 (+/- 0.2) Volts on the collector at the MINIMUM Attack setting.

It is my experience that if you're sporting around 200µA of leakage and set it up this way that the sweep of the Attack pot becomes a very useful tool in this pedal. At minimum the sound is akin to medium/strong overdrive kind of mild distortion…as you start dialing it up you begin to hear more and more fuzz, than more and more compression. Eventually, as you near maximum the signal becomes so compressed and fuzzy you start to hear a volume drop. There is definitely a sweet "range" (not spot) with this method and it's usually between (roughly) 8 and 3 on the Attack knob. Unity gain, no matter the Attack setting, is almost always around 1PM on the volume knob.

Last, a couple notes. I have no idea why Gibson chose to go with the 470K. It makes the pedal almost impossible to bias to where it will work at all, let alone well. I went through a process where I held everything constant and only changed out the Q2 transistor (using all the same make and model) with leakages ranging from below 100µA to over 1000µA (that's 1 milliamp!). It wasn't until you get over 500µA leakage that you start getting good strong sound and you need to get near 1000µA to start to gain some functionality from the Attack pot. They must have had some seriously shitty RCA 2N270's in mind when they picked that 470K. I've found, using my method and RCA 2N408 transistors (the replacement for the 2N270) that my trimmer usually ends up around 100K. I have one old black can RCA 2N270 that has leakage so high, and it's so unstable, that I have never bothered to get a reading on it using RG's method. It starts off around 800µA leakage and just shoots up from there like a rocket. I put that in for Q2 and it produces some awesome fuzz sounds and gives the attack pot almost as much functionality as my method…but it's so damn hissy and noisy when you're not playing it's unusable.

Here is a clip of what mine sounds like. I basically play the same lick from 7PM (minimum) through 5PM (maximum). It was recorded with a portable Edirol digital recorder set in front of my Fender Champ 12 and using a Gibson SG on the bridge pickup. The compression and limiters on the Edirol are off and the amp volume is set very low.

[soundcloud url="http://api.soundcloud.com/tracks/86405311" params="color=ff6600&auto_play=false&show_artwork=true&show_playcount=true&show_comments=true" width=" 100%" height="81" iframe="false" /]

Here is a picture of one of my builds inside and out.

Image
Image
Last edited by rocklander on 17 May 2013, 22:35, edited 1 time in total.
Reason: op asked the text to be changed slightly, so I did

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Blues1911 (25 Aug 2015, 16:56), fuzzfiend (16 May 2013, 20:43), jrod (16 May 2013, 20:33), kzustang (02 Oct 2014, 22:35)
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Re: Maestro - FZ-1

Postby lowbrow » 16 May 2013, 17:37

I can't seem to edit the above post...to fix the soundcloud link I can't get to work. Harumph. Well, here is a direct link:

https://soundcloud.com/lowbrowindy/new-fz1-clip

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Re: Maestro - FZ-1

Postby fuzzfiend » 16 May 2013, 20:43

Lowbrow, that REALLY sounds fantastic (I think I drooled on myself a little while listening to the clip)! And THANX for sharing your insights! What are the TO-92 and 8-pin DIP in your build? Also, are you using the LM337 for extra regulation on a potentially shakey power supply?
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Re: Maestro - FZ-1

Postby lowbrow » 16 May 2013, 21:18

Thanks fuzzfiend! :D

The silicon transistor is a 2N3906 I use for power isolation (emitter follower again) and is part of a charge pump (7660SCL) and voltage regulator (LM337) circuit to give me -3 volts with respect to ground to power this beast. I dislike batteries so set up all my old positive ground germanium fuzzes this way. That way they can be powered off a regular Boss style power supply, One Spot or what have you....
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Re: Maestro - FZ-1

Postby lowbrow » 17 May 2013, 20:52

Looking at this again I realize I made a serious error I need to point out. Should have not relied as much on memory and more on my notes. Hopefully a MOD will fix it at some point. The fix:

"I set the Attack pot on MINIMUM and adjust the trimmer till I'm getting between 0.2 and 0.3 volts on the collector."

Should be changed to:

"I set the Attack pot on MAXIMUM and adjust the trimmer till I'm getting slightly over 0.2 Volts...try for less than 0.4 Volts on the collector, but it will be touchy and kind of difficult. When you do this, you should see in the area of 2.7 (+/- 0.2) Volts on the collector at the MINIMUM Attack setting. "
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Re: Maestro - FZ-1

Postby Masuto » 14 May 2014, 07:36

Hi brothers.. i built a maestro fz1 using this layout:

http://www.aronnelson.com/gallery/main.php?g2_view=core.DownloadItem&g2_itemId=10867&g2_serialNumber=2

And... erm it is not working. Last time i built a fz1 i seem to remember there were a ton of wrong layouts in the realms of webdom and perhaps this is one of them...I wouldnt like to start from scratch as it is pretty neat looking. Any one would like to chime in to tell me what is wrong with this layout and suggest an easy fix without having to tear everything apart?
Cheers
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Re: Maestro - FZ-1

Postby jrod » 14 May 2014, 14:53

Masuto wrote:Hi brothers.. i built a maestro fz1 using this layout:

http://www.aronnelson.com/gallery/main.php?g2_view=core.DownloadItem&g2_itemId=10867&g2_serialNumber=2

And... erm it is not working. Last time i built a fz1 i seem to remember there were a ton of wrong layouts in the realms of webdom and perhaps this is one of them...I wouldnt like to start from scratch as it is pretty neat looking. Any one would like to chime in to tell me what is wrong with this layout and suggest an easy fix without having to tear everything apart?
Cheers


Hey Masuto...One thing wrong with that layout is it's missing the 470K from Q2 base to +3V. I've never build this one, so I don't know if it will work without it, but I would imagine the bias of Q2 would be way off without it.

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Re: Maestro - FZ-1

Postby jrod » 14 May 2014, 15:10

Also, the 56K is in the wrong place. Looks like this layout is based on the incorrect schematic on Fuzz Central.

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Re: Maestro - FZ-1

Postby Masuto » 16 May 2014, 07:11

Ok...any chance for you to point me to a verified layout for veroboard?
I built the Grrrunge one and it isnt working. I built the aforementioned one and it is not working. How about the Renegadrian (it sports a trimmer instead of the 1k5 resistor...!? Google is not helping. I hope you will.
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Re: Maestro - FZ-1

Postby modman » 25 Nov 2014, 14:00

from a current Ebay auction:
All operational parts of pedal are original with orig switch and pots working perfectly, plus orig cord and untouched circuit board, only non-original part is the battery holder, replaced with identical NOS part. Enclosure has some rust, but all screenprinted graphics are clean. Original knobs in good condition, minor wear.”
These come up on ebay very rarely, and never in the UK! Behold the father of all fuzz pedals, the first ever stompbox of any kind, the sound of Grady Martin and Keith Richards - fuzzy Satisfaction and primitive proto garage punk glory guaranteed!

I don't need to oversell it - it's a first (and only) run Maestro FZ-1 Fuzztone, made in 1962, 52 years ago, it probably sat gathering dust in a music store somewhere in the USA until the summer of 1965, when the Rolling Stones released Satisfaction and guitar music changed forever. It's in good condition and 100% as it should be, all original apart from the battery holder, which is an NOS replacement part, identical to the original - See condition box for the detail.

There were only around 5000 of these little monsters produced in '62; Maestro issued the 2nd version, FZ-1A, with one AA battery instead of two, in the autumn of '65 after the first batch sold. Still a cool fuzz, but not the same muscle as the FZ-1.

Yes the opening bid is high, but rather than setting a reserve and have everyone wait around for a week playing games, the first bid could be the winner. Have you ever seen one for sale in the UK before, ever? Think about it. Compared to what you'd pay in a shop, it's a good deal, and it won't be back. There's also FREE SHIPPING in the UK.

Other locations - please wait for confirmation of shipping in my invoice before paying - please note that the rates given are NOT INSURED, and insurance is expensive - see http://www.royalmail.com/price-finder - we can discuss options at auction end /if and when.

Thanks!
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Re: Maestro - FZ-1

Postby ljn » 30 Nov 2014, 01:02

Hi there. Very interesting stuff here. I've been wanting to build one of these, myself but can't find parts to do it. These old fuzz circuits sound way better than what's being produced these days. How does it respond to having a wah placed behind it?
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Re: Maestro - FZ-1

Postby Masuto » 25 Mar 2016, 13:19

My latest clone.. How does it sounds to you?
Fender strat>pedal>ac4tv>iphone mic

https://www.dropbox.com/s/odzftcbdcp2mi ... 1.m4a?dl=0

Q1 hfe 79 lkge 0.12mA

Q2 hfe 168 lkge 0.53 mA

Q3 hfe 131 lkge 0.70 mA

I tried inverting Q3 and Q2 but the distortion was oscillating..
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Re: Maestro - FZ-1

Postby ljn » 05 Apr 2016, 08:32

I've been experimenting with this circuit and have found that it's kinda like the Tone Bender MkI. What I mean is that it can be tuned in similar ways. For example, the 470k resistor on Q2 base can be tweaked to either increase or reduce the distortion. If your transistors don't have enough leakage, you can sorta "cheat" by adding resistors to the B-C junctions of Q1 and Q3. Not really a "purist" approach, but it will work. If the transistor has too little leakage, it won't pass signal.
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