[Zelfbouw] Fuzz Face topic

[Toolshed]

test

[Toolshed]

Ok. Ik heb al een keer eerder gereplied in een ander topic, maar toen was die weg :S

Ik heb samen met een vriend van me besloten om ook een fuzzface te bouwen. Maar na een dag knutselen kwamen we toch op wat problemen uit. We hadden een stuk of 8 AC128 transistors, om ze te matchen, en nog wat 2n3906's om de hybride schakeling uit te proberen.
Na het selecteren van een aantal AC128's die in de goede gain marge vielen gingen we testen, maar het geluid was echt zwaar ruk. Een natte scheet geluid.
Wat opviel was dat de input boven een bepaalde waarde uit moest komen voordat er uberhaupt geluid uit kwam. Dus wij dachten dat de bias waardes van de 2 transistors niet goed is. Na veel gepruts met weerstanden kwam er een beetje een redelijk geluid uit. Zover zijn we nu dus. Klinkt nog steeds echt niet mooi, maar het 'gate' effect is weg. De hoge tonen komen er echt niet mooi uit, de bas klinkt dus wel oké. Nu is onze vraag: hoe komt het dat de bias-waardes niet kloppen, terwijl we het helemaal volgens het circuit gebouwd hebben, en de gains en leakage van de AC128's gemeten zijn. En maakt het uit dat er op de condensators die we gebruiken staat dat ze 60 volt zijn? Ik hoop dat er iemand is die onze problemen herkent.

[bigtonemusicbrewery]

Just because you matched the gain doesn't mean that it's the right gain for the circuit. What is the hfe of the transitors you are using? In my experience, AC128's are typically too low gain for the fuzz face. AC125s or AC126s are much better. 4.5v means nothing. It's just a guideline. You are probably going to want to raise the voltage to the collector. You can do this by increasing the 470 ohm resistor to 560 ohm or somewhere in the mid 500's. Also, the fuzz will sound much clearer and crisper if you change the 2.2uF input capacitor to a .047uF.

[Kjiratsiekoedel]

Just because you matched the gain doesn't mean that it's the right gain for the circuit. What is the hfe of the transitors you are using? In my experience, AC128's are typically too low gain for the fuzz face. AC125s or AC126s are much better. 4.5v means nothing. It's just a guideline. You are probably going to want to raise the voltage to the collector. You can do this by increasing the 470 ohm resistor to 560 ohm or somewhere in the mid 500's. Also, the fuzz will sound much clearer and crisper if you change the 2.2uF input capacitor to a .047uF.

why do you always talk english??

[birt]

Just because you matched the gain doesn't mean that it's the right gain for the circuit. What is the hfe of the transitors you are using? In my experience, AC128's are typically too low gain for the fuzz face. AC125s or AC126s are much better. 4.5v means nothing. It's just a guideline. You are probably going to want to raise the voltage to the collector. You can do this by increasing the 470 ohm resistor to 560 ohm or somewhere in the mid 500's. Also, the fuzz will sound much clearer and crisper if you change the 2.2uF input capacitor to a .047uF.

why do you always talk english??

maybe cos he's american? :D

[Javaca]

Bigtonemusicbrewery heeft gepost in het nederlands.
Dat was erg vertederend om te zien. Woorden als "Fuzzface" en "White room" werden ook vertaald naar Pluisgezicht en Witte Kamer.
Erg knap hoe puur hij eigenlijk met het Nederlands omging.

[birt]

Bigtonemusicbrewery heeft gepost in het nederlands.
Dat was erg vertederend om te zien. Woorden als "Fuzzface" en "White room" werden ook vertaald naar Pluisgezicht en Witte Kamer.
Erg knap hoe puur hij eigenlijk met het Nederlands omging.

vooral zijn vertaalprogramma dan :)

[bigtonemusicbrewery]

Bigtonemusicbrewery heeft gepost in het nederlands.
Dat was erg vertederend om te zien. Woorden als "Fuzzface" en "White room" werden ook vertaald naar Pluisgezicht en Witte Kamer.
Erg knap hoe puur hij eigenlijk met het Nederlands omging.

Yes. I made an attempt at Dutch. But since everyone here speaks English better than I can speak Dutch (with the help of a translating program) we decided that I should just speak English.

Zie. hier een kleine steekproef van mijn Nederlands. Ik heb werkelijk geen idee wat ik zeg. Ik moet enkel hopen dat de vertaler goed genoeg zal werken om mijn
bericht te vervoeren. Misschien na een tijdje wanneer ik te weten kom hoe de Nederlandse
grammatica letterlijk in het Engels vertaalt, Ik kan dit hulpmiddel efficiënter gebruiken.

[Antal]

Zie. hier een kleine steekproef van mijn Nederlands. Ik heb werkelijk geen idee wat ik zeg. Ik moet enkel hopen dat de vertaler goed genoeg zal werken om mijn
bericht te vervoeren. Misschien na een tijdje wanneer ik te weten kom hoe de Nederlandse
grammatica letterlijk in het Engels vertaalt, Ik kan dit hulpmiddel efficiënter gebruiken.

Maar dit is nog te begrijpen voor ons Nederlanders, ook al kloppen de zinnen niet helemaal. Ik heb wel eens vertalingen gezien van dat programma van jou die echt kant noch wal raakten. (kijken hoe je dat vertaald) :-D

[H.Manback]

Ok ik ben dus die vriend van toolshed die ff een fuzz face wilde bouwen, en vandaag ben ik met een schone lei begonnen aan een nieuwe fuzz. Na wat soldeer werk was ie dan eindelijk klaar.
Maar, dezelfde problemen waren er weer, hij deed niets met de standaard weerstand waardes. Dit is trouwens het diagram wat we hebben gebruikt;
http://home.zonnet.nl/osbruil/images/fuzzfacetour/schem_fuzz.gif

Omdat we al hadden gemerkt dat met de standaard weerstanden er niet veel gebeurt, heb ik voor de weerstanden van 33k, 470 en 8k2 ohm voetjes gebruikt en nu kan ik ze dus makkelijk verwisselen.
Na wat gepruts met de weerstanden heb ik wel geluid uit het circuit gehaald. Met potmeters heb ik de 33k op ongeveer 200 tot 400 ohm gezet en de 8k2 een beetje lager dan 8k2. Er kwam nog een redelijk geluid uit, maar nog niet echt goed.

Als transistoren heb ik geprobeerd;

Q1; AC128, hFE +/- 100, Q2; 2n3906, hFE +/- 230
Q1 & Q2; 2n3906, hFE +/- 230
Q1; AC128, hFE +/- 65, Q2; AC128, hFE +/- 100


De AC128's zijn getest op leakage, geen van beide kwamen boven ongeveer 250 mV

Wat ik me nu afvraag is hebben we het circuit nu echt zo zwaar mishandeld dat er 'per ongeluk' geluid uitkomt of klopt het dat de waardes zo erg moeten worden aangepast?

Edit: Ik heb nog even de voltages op de collectors gemeten met de standaard weerstanden, dus 33k 470 en 8k2, 100k op de feedback, en op Q1 is de voltage gemeten op de collector 1.3 V en op de collector van Q2 3.3 V. Dit is gemeten met 2n3906 (Silicium) transistoren. Met de 3e combinatie van de lijst hierboven waren de voltages voor Q1 en Q2 350 mV en 6.9 V.

Om het voltage op Q2 rond de 5 te krijgen moest ik de 470 ohm weerstand opschroeven naar 250 kOhm... :???: Toen ik hem daarmee testte kwam er wel geluid uit, maar heel erg clean, vermoedelijk omdat de Q1 een veel te lage spanning op de collector had. Ik snap er in ieder geval helemaal geen reet meer van...

Edit 2: Dat laatste was dus met de twee germanium AC128s

[bigtonemusicbrewery]

Did you wire the pedal for positive ground? People say there is no difference, but I've noticed that there is. Are you sure that you orientated your transistors correctly, ie. your emmitter is pointing in the right direction? You can put your transistors in backwards and it will still work, but it will sound flat. Are you doing this on PCB and if so did you build the board yourself?

I'd also put a 10k trimpot in place of the 8.2k

If you are 100% positive that everything is correct and it still doesn't work, I'd try some different transistors. AC128's never sound very good. And 2N3906's aren't the best choice either. If you wan't to go with silicon, try BC213 (PNP version of the BC108) or BC214 (PNP version of the highgain BC109). Any major electronics distributor should carry them. If you want to go with germanium, try AC126's instead. IMO OC75's are the best germanium transistors for the FF. Even better than NKT275. Phillips and Mullard had factories in NL. It sould be pretty easy for you to find some nice NOS transistors. Check out some old radio/tv repair shops.

[H.Manback]

To answer your questions, yes it is wired positive ground, the transistors are wired correctly, I've looked up the order of the legs by typenumber, and the silicons give a correct gain reading in my multimeter, and no I did not make a PCB :cry: I've wired it by hand. I'm sure that the wiring is correct, so I think I'll try those OC75's you mentioned, I know a shop that definitely carries them. Also I'll check the BC213, both to compare sound and as a reference.
Another thing I'm not sure about is how to measure the voltages on the collector. Does the device have to be connected (input on guitar, output on amp) or does the circuit only has to be closed (I wired it in such a way that it turns on when a jack is in the input). I measure different readings each way.

But I still don't understand, shouldn't the circuit give at least some sound when you use all the normal resistor values? Even with AC128's or 2n3906? I'm not talking about GOOD sound, I mean just some sound. With the resistor values from the diagram the circuit is dead.

Thanks for all your help

[H.Manback]

Ok, I've picked up some japanese transistors, the guy didn't have OC75's laying around. I tried those and a) they can get REALLY hot, and b) the same problems occur.
Somehow, the entire thing won't work with input that is too soft. I think that by lowering that 33k resistor the input just gets amplified so much that I can actually get some sort of sound.
What we experienced was that the effect does work if we put a proco rat in between the fuzz and the guitar, which amplifies the signal. Also when I lower the 33k resistor to 400 the fuzz does make sound, but as soon as I turn down the volume of my guitar to about 7 the fuzz stops.

I'm really running out of ideas here, and I don't want to quit now :-(

[bigtonemusicbrewery]

Ok, I've picked up some japanese transistors, the guy didn't have OC75's laying around. I tried those and a) they can get REALLY hot, and b) the same problems occur.
Somehow, the entire thing won't work with input that is too soft. I think that by lowering that 33k resistor the input just gets amplified so much that I can actually get some sort of sound.
What we experienced was that the effect does work if we put a proco rat in between the fuzz and the guitar, which amplifies the signal. Also when I lower the 33k resistor to 400 the fuzz does make sound, but as soon as I turn down the volume of my guitar to about 7 the fuzz stops.

I'm really running out of ideas here, and I don't want to quit now :-(

The way you are describing the sound makes me believe that you wired your transistors backwards. As I mentioned before, the fuzz will still work even if you put the transistors in backwards, but it won't sound quite right. It will not be very loud and the fuzz won't sustain for very long. It will crackle and break up very abruptly. It's an easy mistake to make. That's why I always try to use sockets. On the schematic, the EMMITTER is denoted by an arrow. Perhaps you are confused because they drew the arrow pointing in (collecting) instead of pointing out. On your actual transistor, there are several ways to determine which lead is the collector and emmitter. A red dot is always the collector. This is more common for glass housing or TO-1 housing. On "top-hat" style housing, they will identify the emmitter with a little tab sticking out to the side. The TO-39 silicon housing is a little trickeir to figure out. But about 90% of the time if you have the flat part facing you and the legs pointing down it goes EBC.

The resistor values allow for a wide range of gains. If you had to lower the 33k down to 400, then there is something definitely wrong.

To check the collector current, you don't need a signal, you just need power. It shouldn't make a difference if the guitar is plugged in or not. Touch one probe of the meter to the negative terminal of the battery. Touch the other probe to the collector. If you are getting a negative reading, just switch the probes around.

[Toolshed]

It's working!! H.Manback is now testing some different transistor configurations, to fin-tune the sound a bit.
The big problem was that the input jack wasn't wired correctly. We now get a proper sound with the original resistors, following the scheme!!! Big party now :D:D

[H.Manback]

Thanks for your patience, bigtone, but as Toolshed mentioned, it was a error with the positive ground. You already asked that, and I was stupid enough to answer that it was positive grounded :oops:. But once I started examining the voltages, I noticed that once my input is plugged in (necessary since the circuit is switched on by a stereo jack) on both sides, the voltages go crazy. Then I traced all the wires and found out that this grounding is incorrect. The problem is that we followed this schematic;
http://smallbox.zeonhost.com/projects/fface/fface.gif

Since this was the clearest picture we found that showed how to wire the jacks, we used this image, but as I now see, it is negative ground. Everything is now solved by wiring it positive ground and I can fuzz all day long! (as long as the batteries don't die:))
I'm not sure if the schematic is incorrect, because the input cap is turned around, and we thought that was wrong because all other schematics have the + side to the input. Maybe turning around that cap and making it negative ground does work, but I don't really want to try it now :razz:

[H.Manback]

doh

[H.Manback]

doh

[bigtonemusicbrewery]

If you followed that wiring diagram and used the orman schematic, then you built a NPN fuzz face. So if you had used BC108's it would have worked.

In the future, I find that the best way to figure out how to wire somethin is to just use the continuity test on your meter.

[birt]

i don't really get it.. negative or positive ground?? :-?
i'm about to wire mu fuzz in an enclosure but i'm not sure how to do it exactly

[bigtonemusicbrewery]

i don't really get it.. negative or positive ground?? :-?
i'm about to wire mu fuzz in an enclosure but i'm not sure how to do it exactly

As anyone who's ever used a pedal can tell you, you turn it on and off by inserting a cable into the "in" jack. When you do this, it completes the circuit's ground. In most pedals, one of the battery terminals is always directly connected to the circuit and the other goes to the stereo lug of the input jack. If you choose to use the positive current to be switched on and off at the input jack then that is considered "Positive Grounding". The opposite would be "negative ground"

Most pedals are negative ground. One of the major reasons is because most pedals use NPN (Negative Positive Negative) bipolar silicon transistors. The original fuzzface is designed for PNP (positive negative Positive) bipolar transistors. While it is possible to build a fuzz face with a negative ground, I would not suggest it. The "fuzz" will sound exactly the same as if it were positive ground, but there would be other problems. You would get a scratching noise when you turned your guitar's volume knob and you would get a loud hum when you turned your guitar's volume knob all the way off.

To wire your fuzz, you can use the diagram in this thread, but switch the red and black wires around...sort of. send the black wire directly to the junction of the 33k and 470ohm resistors. Send the red wire to the ring of the input jack. The white wire represents your ground. Since it is now positive instead of nagative you need to send that to the emmiter of Q1.

[birt]

i wired mine and it finally works :D

but when i turn the fuzz volume all the way up i get feedback allmost immediatly. and when i use the fuzz when my amp is set to it's maximum amount of gain is has some kind of 'broken-glas' sound with the normal fuzz. it also makes the sound if my pick very loud. and it sounds muddy when more then 2 strings ring. I guess i'll have to learn to work with it

i continued testing it and i'm not very happy with the sound right now, it's not smooth enough and when i turn the volume of the fuzz up there is a lot more hum then normal (that normal i guess)
the sound of the fuzz with the preamp of my amp all the way up is very bad, harsh, it rings

[H.Manback]

Me and Toolshed did some more work on our fuzz and we added a "brightness" switch, which toggles between the 2.2 μF input cap and a 0.047 μF input cap. Works great! As bigtone mentioned, this 0.047 μF input cap really brightens up the sound, much clearer. Since heavy power chord riffs sometimes sound better muddy, I added a nice toggle switch. It's a dpdt toggle switch I got from a old stereo from a flea market :).

@birt, de meeste dingen die je noemt zijn best typisch voor zware distortions in het algemeen, het muddy geluid kan je denk ik een stuk verhelpen door een andere input condensator van 0.047 μF zoals ik heb toegevoegd. Het haalt een hoop lage tonen weg waardoor het geluid wat minder zwaar wordt. Over plectrum geluid, voor zover ik weet is dat echt typisch voor een distortion die voluit staat.

[birt]

ja dat dacht ik al maar het is wel vreemd dat ik een rinkelend geluid krijg als ik mijn preamp vouluit zet en de fuzz staat aan

[bigtonemusicbrewery]

ja dat dacht ik al maar het is wel vreemd dat ik een rinkelend geluid krijg als ik mijn preamp vouluit zet en de fuzz staat aan

Did you use positive ground. These are the types of problems you will have when you use negative ground.

[birt]

i checked the positive/ negative ground and i made a mistake, the only power supply i had right now didn't fit the connection in the stompbox so i wired another connection on the effect and accidentally switched the + and -
i'm gonna fix it right now

[birt]

ehm, i switvhed the wires and now i have no fuzz anymore, only hum and a litllebit the guitarsound :o

[H.Manback]

I'm not sure on this, so correct me if I'm wrong, but connecting it with the + and - switched might have blown up your electrolytic capacitors (condensators) since they are polarized.

Maybe you want to double check your circuit with the schematic next to you, you never know what you missed. Also check if you have really wired it positive ground correctly.

Do you have a 9V battery connection as well, and does it give you the same problems?

[bigtonemusicbrewery]

The capacitors should be fine. I really doubt they would be damaged under a 9v load. And having the capacitors in backwards doesn't make a difference. The polarity of electrolytic capacitors is really only an issue when they are being used as voltage conditioners or power filters, which there are none in the FF circuit. The problem sounds to me like you just didn't wire it correctly. Set it aside for a day or 2 and then take another look at it. If you take your mind off of it for a little while, the next time you look at it, the problem usually will jump right out at you.

[birt]

i still can't find the problem
here's a BIG picture
http://users.pandora.be/vandijckheffen/bert/DSC04297.gif
(don't mind the third pot, it's for the booster i'm gonna make)
the wires that go through that hole go to the power supply (the yellow one is + and the yellow/white is the -)
i wired the ground on the pots like the ground is wired in my guitar (and that guitar is silent as a cemetary http://users.pandora.be/vandijckheffen/bert/guildguts1.JPG http://users.pandora.be/vandijckheffen/bert/guildguts2.JPG )

[Toolshed]

Nou, ik heb m'n fuzz face (eindelijk) kunnen testen in bandsituatie. Groot succes! Ik gebruik in de oefenruimte een Marshall Valvestate 4040, en vooral icm met een beetje crunch van de versterker klinkt de fuzz heerlijk.
Ik heb hem eerst getest met m'n Dunlop wah voor de fuzz; toen hoorde ik de wah nauwelijks. Toen a la Hendrix de fuzz voor de wah, in 1 woord, geweldig. De fuzz en de wah zijn een hele goede combinatie, veel sustain, prikt heel goed door de mix heen, top!
Nou ik ga slapen, pfffff (http://www.asvuvolleybal.nl/html/smiles/39)

[H.Manback]

Ghehe, lekkere kick na een jaartje :wink:

Het duurde even, maar nu ging het maken toch een stuk makkelijker :lol: