Relay Bypass: final code

After the crowdfunding campaign, I decided to update the relay bypass code.

Indeed, this first version was nice, but one main drawback that was feedbacked to me is that the switch was activated on release, which was not always very intuitive or easy to handle. Moreover, I wanted to add a "temporary" bypass option in the Montagne Tremolo.

Montange Tremolo Relay Bypass

In this post, I am going to explain a bit the new code and to show you how I did it.

If you have not read my post about Relay Bypass, I highly recommend you to read it before reading this post. All the basics of microcontrollers are presented there.

  Tip! The full code is available on Github. With the relayonpress.c and header.h files, you will have everything needed to code or burn chips.

If you already have a GitHub account, you can Star the project for updates, or Fork it to modify it and make your own Relay Bypass code.

Lets go!

Development Hell: multiple fuzz pedal

Today, I am going to introduce the concept of Development Hell: it is a special place where projects stay when they need a lot of fine tuning before properly work. Unfortunately, I have a few projects that are still burning there, like the one I am going to present today.

It is a multi-fuzz machine! I always felt that a lot of Fuzz are quite a "one trick pony", they have a very characteristic sound that can be modulated by mods, but still sounds "like a fuzz face", "like a big muff"...etc. Moreover, fuzz are usually quite simple circuits, and I find that allowing one spot per fuzz on a pedalboard can quickly be space-inefficient.

So I decided to create a multi fuzz pedal, with no more than 3 different fuzz inside : a germanium Fuzz Face, a Muff Fuzz and a Companion Fuzz, which should provide the 3 main "flavors" of fuzz in this world: a classic warm, soft fuzz face, a "chainsaw", very raspy Companion Fuzz, and a compressed and heavy Muff Fuzz.

On top of that, I added an upper octave generator that allows to combine it with any fuzz, with a potentiometer to adjust the amount of octave. It is based on the Green Ringer circuit, which is a small, but efficient analog octaver circuit.

And of course, I made it fit in a 125B enclosure...

Here it is in its current form:

Hakko FX888D: a $100 high quality soldering station

Let's face it: your good old soldering iron is not always the best pal to work with.

I had some troubles with mine: no support to put it when I busy doing something else than soldering, which can be quite dangerous if it falls or burn something. Moreover, the power cord was quite short and not very flexible, so it was not always easy to find a good "spot" for it in order to be perfectly comfortable. Finally, it takes a long time before getting hot enough to solder, and 30W is sometimes a bit low to solder big potentiometer or jack legs.

So I decided to invest a bit in a soldering station.

After reading a lot on the web, I have found this little gem: the Hakko FX888D, a Japanese soldering station that you can find for $96 on Amazon

Here is mine:
Hakko FX888D

Vintage Maestro Fuzz-Tone FZ1-A (1966)

The Maestro Fuzz-Tone is simply the first fuzz ever! I felt a bit like an archeologist when inspecting this effect ! Someone gave me this one for repair, experiencing some issues with the built-in jack and the switch. Here it is:

Maestro Fuzz-Tone FZ1-A 1966

It is quite in good shape for a 50 years old guitar pedal! The pots allowed me to date it, from 1966. There is a serial number as well, but I do not really know how they work. I think each serial correspond to the number of the unit. Thus, the lower the serial, the older the pedal is. This fuzz is not that big for a vintage fuzz, especially compared to the 1973 Supa Tonebender that I had on my bench before.

At the front of the pedal, there are two controls: Volume and Attack (translate by "Fuzz"). It is the second version of the Fuzz-tone, the FZ1-A. The two knobs are also original, and are the same "reflector" knobs used on vintage Les Paul.

Maestro Fuzz-Tone FZ1-A 1966

Indeed, the pedal was made by Gibson in the same factory as the Les Pauls, in Kalamazoo, Michigan! Thus, a lot of parts are shared with vintage Les Pauls: the knobs, potentiometers and some low value capacitors. I believe that it allowed Gibson to lower a bit their prices, selling this pedal for $40 at the time (which should be around $300 today though...). Gibson even included it in some bass produced at that time, like the Gibson EB-0F, Gibson EB-SF 1250 and Epiphone Newport EB-SF!

Inside, the circuit is dead-simple. Three pnp transistors, wire on an eyelet bakelite board create the saturation. They are Motorola 2n2614, old germanium transistors. The original FZ1 used germanium 1n270 transistors, whereas the FZ1-A version used Motorola 2n2614. It has also old carbon-comp resistors, from the sixties!

Maestro Fuzz-Tone FZ1-A circuit

The electrolytic capacitors had been replaced (very common, old electrolytic transistors tend to leak, and are often replaced in vintage builds like this one), the yellow Suntan capacitor is not original as well. Apart from that, all the rest is original! It feels quite extraordinary to discover a perfectly preserved circuit like this one when opening the pedal, it feels a bit like opening Toutankhamon's tumb!

Close up on one of the transistors:

Maestro Fuzz-Tone FZ1-A transistors

The fuzz has only one input, and a jack allows you to connect it directly to your amp. Well, it is one the first guitar pedals, so pedalboard were not really an option at that time!

History of the Maestro Fuzz-Tone

The Maestro Fuzz-Tone FZ1 was the first fuzz  pedal ever! In the early 50s, blues guitarists started to push their amps to make it distort and create a weird, unusual guitar sound: saturated guitar sound. Some players even made holes in the speaker to make the distortion even greater! In 1961, Grady Martin bought a faulty transformer creating a weird distortion, and recorded a song called "The Fuzz" with it. The name "Fuzz" was born!

The song became really famous, and many artists did want to use the same sound. However, the transformer died shortly after the song was recorded. Glenn Snody, the original owner of the transformer and Revis Hobbs, a radio engineer, wanted to recreate the sound of the transformer using transistors. And this is how the Fuzz-Tone circuit was created! Snody and Hobbs showed it to Gibson, who developed a prototype and commercialized a first batch of 5000 units in 1962, selling it for retail price of $40 at the time.

The original Fuzz-Tone advertisement is quite amusing, they say it can sounds like an organ or mellow woodwinds... I would rather say: a huge screaming dirty nasty sound that will crush your ears lol! Here is the record:

I do not know how they made the recording, I cannot reproduce any of these sounds at home! This record feels like listening to the really birth of rock...

The Fuzz-Tone was quite a commercial failure: besides the 5000 units shipped in 1962, Gibson did not sell any other fuzz pedal until 1965! Indeed, in 1965, the Rolling Stones issued "Satisfaction". Keith Richards did use the FZ1 on the records to make the main riff. It was used to emulate the sound of a horn, because the Stones did not have horns in their band at the time.

The Fuzz-Tone became then really famous (the hype for guitar effects was already there :) ), and Gibson sold more than 40 000 units later! It also inspired many other manufacturers that begin to create other fuzz circuits like the Tonebender, Fuzz Face...etc.

Versions and other models

The FZ1 was declined in several models. The FZ1 was quite a commercial failure, and Gibson did not make more of them... It is also the more collectible version fo the FZ-1, as only around 5000 units were manufactured (less than the Klon Centaur!). You can distinguish between these four version by looking at the front of the enclosure. Here are the four main versions of the FZ1 (spot the differences!):

In 1965, the Rolling Stones made it famous, and Gibson issued another model, the FZ1-A. It did not use the same transistors (2n2614 instead of the original 2n270), and used only one AA battery!
There was a few change to the circuit: the two 20uF coupling electrolytic capacitors were replaced by 1uF ones, and the second collector resistor was changed to 10k instead of 1.5k, maybe to compensate the lower voltage. The name of the model is clearly written on the front of the enclosure, with "FZ-1A" instead of "FZ-1".

It was first manufactured in the Kalamazoo factory in Michigan, and then, after 1968 (not so sure about the exact date though), FZ1-A were later manufactured in Lincolnwood, Illinois. The location of the factory is written below the Gibson logo. The serial numbers are also higher (see below).

Finally, the FZ1-A was a reissue in 2002, exactly reproducing the circuit and the enclosure, with the same transistors! Fortunately for us, it was manufactured in Nashville, Tennessee, which is written just below the Gibson logo. Also, the reissues do not have a serial number engraved.

The FZ1 also had successors. Later on, Maestro issued the FZ1-B, which uses silicon transistors. The circuit is thus quite different, powered by a 9V battery, and the Fuzz does not sound quite the same. It is less saturated, and a bit buzzy. It is pictured on the left here:

Later on, the FZ1-S model was issued in a huge enclosure, with a very cool looking metallic circle. It has three controls, and a switch for the tone control: you have guessed it, it has almost nothing to do with the original Fuzz Tone! It is closer to a Fender Blender or an Univox Super Fuzz (no octave though).

Serial numbers of the FZ1: date your pedal easily

Sometimes pots have been replaced, and the pedal can be hard to date. I tried to decipher the year of each serial number. This is not an official statement, however, I have emailed Gibson about it, maybe they have more infos to give me. In the meantime, if you are the lucky owner of a FZ1, you can give me the serial number and the date of your pedal. Thus, we can complete the table!
Model Year Factory Units shipped Min-Max
serial seen
between ?
FZ1 1962 Kalamazoo, Michigan 5461 870-4628 1-5461
FZ1-A 1965 Kalamazoo, Michigan 3454 6174-? 5462-8916
1966 Kalamazoo, Michigan 20943 10665-21354 8917-29860
1967 Kalamazoo, Michigan 6625 22933 29861-36485
1968 Kalamazoo, Michigan ? 42276 36486-42276
FZ1-A Lincolnwood, Illinois ? 43762-44537 43762-44537
FZ1-B Lincolnwood, Illinois ? No serial number no serial
FZ1-A Reissue 2002 Nashville, Tennessee ? No serial number no serial
The easiest way to do it is to do these steps:
  • Find the name of the model (FZ1 or FZ1-A?)
  • Find the place it was made (Kalamazoo, Lincolnwood or Nashville?)
  • Read the serial number
  • If your pedal is not in the serial numbers indicated above, open it and look at the potentiometers. The date should be on it, like on vintage guitars.

Circuit analysis: how does it work?

As mentioned before, the circuit is based around three transistors:
Maestro Fuzz-Tone FZ1A schematic

Like usual, let's divide it in functional parts:

Maestro Fuzz-Tone FZ1 schematic

It has a negative polarity because of the PNP transistors, and use only one AA battery, so 1.5V only!

Input stage

The input stage is basically a small buffer that also cuts some bass.

input stage FZ1

First, there is a coupling capacitor of 0.01uF. It avoid parasitic DC current to enter the circuit, and also filter some low frequencies: you loose a bit of bass. A 1M resistor connected to ground prevents noises when the pedal is switched on.

The first transistor is wired in emitter follower (not really common in guitar pedals), in order to adapt the impedance of the guitar signal. The emitter is indeed connected directly to the power supply. Thus, it has a gain of around unity, and does not amplify the signal.
There is another electrolytic coupling capacitor after this capacitor.

Saturation stage

This is where the fuzz happens! A transistor is pushed beyond its limits and saturates because of the gain that it too high.
saturation stage FZ1
The bias of the base of the transistor is defined by R4, R5 and R6. The fuzz knob is wired as a variable resistor, in parallel to R6. So when the Fuzz knobs changes value, the bias of the base of the transistor varies. Basically, the more you turn the "Fuzz" potentiometer to the right, the higher is the current going through the base of Q2.

Basically, there is too much current going to Q2, which creates saturation: the fuzz is there!

Note that the emitter of the transistor is wired directly to ground to make the gain of Q2 maximum! 10k is also quite a high value for the collector resistor, and it helps increasing the saturation even more. If you replace it by a bigger value, you can increase the saturation even more!

C3 is a coupling capacitor that prevents any parasitic current from the collector to go in the circuit.

Output stage

This stage amplifies the signal and can even boost it a bit to get a nice volume output.
maestro FZ1 output stage

It is very simple : the Q3 transistor amplifies the signal a lot (and saturates as well : there is no emitter resistor, plus a high value collector resistor = very high gain!).

The C4 capacitor is a coupling capacitor that prevents parasitic DC current to go out. C4 also cuts some bass, as it is quite a low value (10nF). If you use a bigger value, the pedal will be more bassy and muddy. I actually like it with a higher value, it really changes the character of the fuzz.

Finally, a volume knob sends more or less signal to ground. If you turn the potentiometer to the right, the resistance increase, and more signal goes out the circuit instead of going to ground: higher volume output! It is the same control that is used in the Fuzz Face.

There it is! I hope that this post was helpful and fun to read! If you have any remark or question, post a comment below!
If you liked this post, thank me by linking Coda Effects Facebook Page! You can also follow Coda Effects on Instagram and Twitter.

To go further

14 electronics suppliers for guitar effects (with pros and cons)

Finding good electronics suppliers is a key issue when building guitar effects professionally. Indeed, they play a huge role in traceability and quality of the components (where the components come from and what they are exactly), and also the price of these components. Sometimes, they can also add delays if they are bad with handling orders and shipping it quickly.

Goods electronics suppliers are the root cause of a good build quality for a pedal builder.

With my crowdfunding project, I have an intermediary position. I cannot order directly from manufacturers (because I would have to order thousands of units at least), but I can order from electronics wholesalers!

Already 95% of the components have been ordered, and I already received quite a lot of parts! Here is a picture of the switches I got this morning (more pictures will follow in a next post):

End of the crowdfunding campaign: what's next?

Here it is! The crowdfunding campaign is over, with a lot of success!
Thank you all for your support, Coda Effects is on the good tracks thanks to you!

crowdfunding ended

Let me show you some numbers:
In this post, I want to present you how I am going to schedule everything. As mentioned on the project webpage, I will write blog posts about the perks and pitfalls of making a series of pedals. One the pitfalls if to make an impossible-to-follow delivery schedule for sure!

Here is my schedule:
  • Receiving the money (one to two weeks): I will be then allow to see how much is left after the Ulule, Paypal, and French state taxes are off the collected amount of money. Indeed, almost 23% of the money will go to these different taxes. (No worries, I made the calculations before :) ). It should take one to two weeks to get all the money ready for ordering the parts!
  • Ordering the PCBs, enclosures and components (one to two months): one of the most crucial step! Thanks to the prototypes I have already made and my experience, I already selected a list of reliable suppliers. However, the delays can be quite long due to their localizations (USA, China for the PCBs, which can cause delays due to customs). At this step, some "surprises" can also happen and delay the shipping of the PCBs / kits / pedals. Everything should be fine with the suppliers I selected, but you never now! One to two month seems like a reasonable delay for ordering and receiving all the parts.
  • Drilling the enclosures, making the kits & effects (two weeks to one month): the fun step! I will do my best to make it as quick as possible, but always with great care about the project. I will have 27 pedals to make, and everything else will be kits (which implies only drilling). I already thought about tips to make it easier and quicker, which I will share with you in a next post.
  • Making videos and build doc (one to two weeks): before sending the kits, I really want to make a tutorial video to show you how to assemble your kit. It will prevent a lot of mistakes I think, so I think it is worth the wait! 
  • Shipping everything (one week + shipping time): I am currently evaluating which shipper I should use, for now I am considering the French post offices, which are quite good regarding tracking, delays and costs.
There it is! It is quite a lot of work to do. The maximum delay time is around 4 month (February 2017). I know it is quite a long time, but I hope to make it as quick as possible!

You will of course be informed about how it goes on a weekly basis.
If you have any suggestion or comment to make, do not hesitate to post a comment!

Finally, in order to follow the project daily, like the Coda Effects Facebook page, or follow Coda Effects on Instagram or Twitter.