Silicon Fuzz Face curse?

[bbr6704]

Hi there, pretty new here, even if I subscribed a long time ago...

I have some questions these days, as I'm facing some problems (a curse?) building a silicon fuzz face...

I already built some pedals (boosters, overdrives, a tremolo and fuzzes : a one knob colorsound, and a Black arts Pharaoh).

So, even if I don't consider myself as an expert, I have some knowledge and knox the topic a bit.

But I'm on my third circuit trying to build a fuzz face : first a solidgold fx 6 was 9 fuzz (didn't worked at all), an Analog man sunface (some fuzz sound, butt covered with a lot of unwanted noise (hum, hiss) and lastly a Creepy fingers silicon fuzz face. This one works, but as soon as I stop to play, I have a lot of noise (like an unplugged jack in an high gain amp).

I'm working on vero boards, taking my schematics form Tagboardeffects, so I trust them when they are verified, and guess the problem doesn't come frome there.

Here are the schematics I'm relying on :

https://tagboardeffects.blogspot.com/2017/12/solidgoldfx-if-6-was-9-bc183cc.html

https://tagboardeffects.blogspot.com/2013/03/analogman-sunface-bc108.html

https://tagboardeffects.blogspot.com/2013/04/creepy-fingers-effects-si-fuzz-face.html

I've checked my circuits, components, trannies orientation, ground... Everything seems to be fine.

So, I don't see no explenation,

The only two things that still can be an explenation are :

1. My soldering Iron may be too hot, and so my solders aren't top notch (I've recently changed, but I'm afraid I bought a too powerfull iron),

2. My trannies are all from the same batches, so have similar Hfes. So I can't respect the rule of Q1 Hfe < Q2 Hfe.

Have you got any other ideas? things I could check before I get mad?

Thanks in advance!

[Plexi]

Fuzz Face isn't as simple as it seems. There's many things to check to get this circuit sounding right. The main and most important is transistors bias. Then which transistors are you using w/which hfe.

Did you check the voltages?

[bbr6704]

Fuzz Face isn't as simple as it seems. There's many things to check to get this circuit sounding right. The main and most important is transistors bias. Then which transistors are you using w/which hfe.

Did you check the voltages?

Thanks for your reply,

Not yet... I stil have to find for what voltage to find where...

I'm diggin this subject. So surprising the "simplest" circuit to build seems to be the harder to make right...

Can I follow the GGG indications on Q1 and Q2 voltages as a guideline?

Q1 Collector 1.4v, Base 0.6v, Emitter 0.0v

Q2 Collector 4.5v (if you use a trimmer, you can set the voltage), Base 1.4v, Emitter 0.8v

[pinkjimiphoton]

first off, welcome to the forum!

your iron being too hot won't give you worse solder joints. but it COULD be melting your transistors. and caps.
you gotta be really quick.

silicon fuzzfaces SHOULD be rather easy, usually they are.
noise is likely from fried components. damaged transistors will get horribly noisy.
but it also sounds like you may have some reverse beta issues on the transistors from the description.
all of these are npn, so shouldn't be too hard to get going.
the sunface i'd go a 10k for the sunpot. i always thought that mike's version with a 5k doesn't allow enough tone. ok for fuzz, but... 10k will give you more ability.

do you have any way to read the gains on your transistors? if so, put the weaker one in q1.
if they all read the same, no big deal.

you BIAS from the collector to b+

you set GAIN by small resistances between emitter and ground. so you can "limit" the gain of a transistor to
get it more in the "ballpark". for q1, that means if both transistors are the same gain about, would get a slightly larger resistor than q2.

add say, 47 to 220 ohms between e and ground on q1... bigger resistor, softer the gain. smaller? more gain.

for q2, approximately halve the value of the resistor you used on q1. so say ya go 220r on q1, try 47 or 56 or 100 or 120 r on q2. put it between e and pin 3 of the fuzz pot. boom. now ya got approximate gains to work with.

make the c resistors trimmers. 10-20k should do fine. this will make your life MUCH easier.
to start,  turn each trimmer to half way. then you can dial 'em both in a little at a time til it sounds good.

the bane of vero builders everywhere is solder bridges and tin whiskers that seem to grow sometimes in inconvenient places. before wiring stuff, take a single edge razor or similar and run it between the rails on the vero with a bit of force to  clear any stray solder bridges.

check for bad joints. sometimes you gotta reflow. in that case, suck the solder out with a solder sucker, or if you don't have one, desoldering braid (which is for cleaning up, not for desoldering, btw)... if ya don't have either, a scrap of copper shielding from an old guitar cord and a bit of electronic flux will work.

odds are, its a combo of solder bridges/bad solder or too much heat. try to keep all connections under 1 second.
how? well, the best way is to pre-tin anything that's likely to get damaged, like lugs on switches, caps, or transistors.
just a tiny bit of solder is all ya need. then when ya stuff it in the board and solder it, all you have to do is kiss it.

no worries. you WILL figure this out.

but first

we need pictures of the problem builds. front and back of the veros, and the more detail you can get us, the better.

next, we need voltage readings for the transistors. connect your black meter lead to the - terminal of your power supply, then on a 20 volt range or so, use the red meter lead to E B C of both transistors, and write down the voltages. that will help us help you.

for the mating buffallo noise when ya turn your guitar off, its ALWAYS bad ground somewhere... well, 99% of the time. if it's NOT, then you may have to dodge and put a @#$%in huge cap across the power rails... think 2200uF or so should nuke just about anything.

you also wanna add a power supply to these pedals... they usually aren't added to a lot of tagboard projects.

very generally, if you put a small resistor...47-100r or so in line with the + power supply will help as a "choke" to keep noise down... then put a 1n400x (1, usually, but any of the 4000 series would do), a 100uF and a 2.2nf cap between the rails in parallel,  that will give you a solid power supply section where your power will be filtered by the resistor and big cap, the diode will protect the circuit from reversed polarity or overvoltage, and the tiny cap will send rfi to ground for ya.
make sure the band on the diode and the plus side of the big cap go to +.

hang in there, hollah back. you'll get this. i got faith in ya, and we've built millions of these suckahs on this here board!

peace
PjP

ps no, you can't follow the ggg recomendations for voltages, those are for pnp circuits. npn tends to be quite different.

[bbr6704]

Thanks pinkjimiphoton,

I'll check that tonight! (some thing allready have been, some other don't, so I'll continue...)

I want to, and I will (we will, all of us here) sort it out! 

[pinkjimiphoton]

i gotta gig tonite bro, so will check back when i see the next update posted. no worries, we WILL get you a fuzzface working. promise

[Mark Hammer]

As grateful as I am to those who put in the work to provide tagboard layouts, I personally loathe the stuff, primarily because strip-board/veroboard/tagboard obliges layouts that do not visually correspond to schematics very well.  I find that makes troubleshooting substantially more difficult.  But that's me.  If you prefer them as a construction method, more power to ya.

Have you verified that the transistor pinouts assumed by the posted layout are identical to the pinout on the transistors you used?

[Fancy Lime]

I, too, must admit that my "doesn't work and I cannot seem to debug it" rate on strip board is embarrassingly high. Like, nothing ever works right away and 50% or so cannot be salvaged, ever. I never had that with perf board or point to point. So if I had the same problem you are describing, first thing I would do is try and find a perf layout and see if I could get that to work or if it has the same basic kind of problems.

Andy

[pinkjimiphoton]

dammit jim, we need voltages!!

we're doctors, not mind-readers!!!

[bbr6704]

Thanks for all your kind replies.

Here are the voltages I get :

Analog Man Sun Face (with BC547 in Q1 and Q2) :

Q1 E : 0v, B : 0.61v, C : 1.18v

Q2 E : 0.71v, B : 1.18v, C 9.13v, and the Sun face (bias) knob doesn't change thongs that much, from 8.90 to 9.20v approx, I guess there is a problem somewhere with this knob...

Creepy fingers Si  FF (with BC107B in Q1 and Q2)

Q1 : E : 0v, B : 0.58v, C : 1.27v

Q2 : E : 0.68v, B : 1.29v, C : 3.59v.

Pictures are coming soon!

[bbr6704]

According to this page : http://www.home-wrecker.com/sili-face.html

the voltages on the Creepy fingers, as on Analog man's Q1, seems ok.

There is a problem on the Q2 of the Analog man, for sure.

Anyway, here are the pics :

Analog man :





Creepy fingers :





Maybe not the best pictures of the forum, but I hope they can help... 

[pinkjimiphoton]

getting ready to leave for my thursday gig, i will take a peek in the morning

[mac]

Sunface
Pinout is ECB and EBC. Double check this.

Others,
In my experience a pf cap to cut highs at Q1 can make funny things. And if there is another cap at Q2 you have a positive feedback path from Q2C to Q1B.

mac

[duck_arse]

As grateful as I am to those who put in the work to provide tagboard layouts .......

sometimes the layouter just doesn't do enough work on his/her layout, and posts a BC108 fuzz for example with non-BC transistor pinout layout.

Have you verified that the transistor pinouts assumed by the posted layout are identical to the pinout on the transistors you used?

and in both the sunface and the creepy fingers, the laid-out pinout requires the builder to twist leads to fit the lay-outers whim.

[bbr6704]

Yrs, I double checked the pinout orientation, and twisted the legs. To me, it's ok...

As you say (or write), I've looked at the perf board thing.

I've been in vero for years because of the availability at Tagboard, and the verified thing, but perf board don't seem that much complicated.

I think I'll try those circuits on perfboards.

I'm also waiting for a lower watt/temp soldering Iron, I've orderded this model : https://www.kurtzersa.com/electronics-production-equipment/soldering-tools-accessories/ersa-soldering-irons-sets/micro-soldering-irons/produkt-details/0910bd-1.html

It should be easier to work with this one.

So I guess I'll give perf board a try, always thought it was harder, or "less good" than vero, but I could have been wrong... (and the more compact layout plus on board pots seems a good thing to me!)

As we're talking about that, any "reference tutorial" on perf board populating/soldering?

[pinkjimiphoton]

to me, it looks like ya may have a solder bridge here on the sunface




try running a blade between the rails on the vero.

to me, it looks like the bias knob smoked on the sunface. you didn't post the +  voltage coming in, but if it's the same 9.13 that pot is shorted and that's not only what your problem is, but also why the sunface knob isn't working.

did ya get pots from tayda by chance? i've been seeing a LOT of pot failures lately in all kinds of circuits. i don't think the alpha's that are so prevalent are legit, and suspect they're being knocked off in china.

i've had brand new pots out of the bag die from there. either go open, or short internally some how. sometimes they let out a puff of magick smoke, sometimes not...
the pot may even test ok with a meter, until ya put it on your wiper and pin 1 or 3 and watch as you sweep the pot... and suddenly it freaks out. what happens is too much current draw will obliterate the carbon track in a spot, and the pot will seem ok until ya reach the damaged area, then BLAMMO. dead circuit... and usually you'll go nuts before ya find it.

i had this happen with a couple pea%^&*s i built for MLA. i got blamed for shitty builds <ha!> and it was the damn pot failing. in each case, the a1m gain pots would have a couple dead spots in them... where you could turn it all the way down and it would kinda work, and let you turn it up about half way... then above a certain point, it would cut out or turn back down again! replacing the pot solved the problem. i've built hundreds of them without the problem, so i doubt its the circuit,  less likely me <tho possible> and most likely faulty manufacturing with substandard carbon tracking... too thin? missing? broken? beats me.

try replacing that pot and see if it will fire up. making popcorn and rolling another one...