Fuzz Face troubleshoot

[rtrags]

I realize there has probably been several (if not hundreds) of these posted from people who are new, but I have been unable to find any that answer my specific questions. I am trying to clone an dallas arbiter fuzz, based on this schematic http://fuzzcentral.ssguitar.com/fuzzface.php it seems easy enough but I am having issues and hope I could get some help.

I have breadboarded the entire schematic but I am confused about the power supply:

- What is the difference between the ground and the negative lug of the battery? According to the schematic the input jack sleeve is grounded and the input jack ring is sent to one of the terminals of the battery.

- Is the negative termanial of the battery not also ground? Also when grounding all the points that need grounding, is connecting them to the same bus on the board sufficient? I have also found a few places that send -9V to the 470 and 33k resistors to power the circuit. What is the difference between these two. I am using PNP germanium transistors I ordered from small bear. The final issue I have, and I believe is a result of my power supply problems, is that the base of Q1 is seeing 9V.

-Since i have been messing around with different power supply configurations, is there a chance that i have damaged any of the components by trying to push 9V in the wrong direction?

I have looked at countless fuzz face schematics online and the variations are confusing and sometimes in conflict. Any help would be greatly appreciated, thank you.

[rtrags]

I just measured the voltages for the leads of my transistors with a +9V going into the junction of 470 and 33K (powering the circuit)

Q1:
B=0.91
E=0
C=1.01

Q2:
B=1.01
E=0.67
C=1.13

According the sheet of paper that came with my transistors (from small bear) with a 9V supply, the Q2 collector should see 4.5V

[23]

you are using the positive ground schem, right?

[rtrags]

what do you mean by that?

[LucifersTrip]

what do you mean by that?

that you used the correct schematic:



where the ground is (+)

the 33K and 470 go to (-)

[rtrags]

then yes I am using positive ground. I guess I am confused as to the terminology of ground. since in this schematic the battery's positive terminal is being used as ground (connected to the ring of the input jack), how does this differ where the other grounds are (Q1 emitter, middle lug of both pots....)? should they all be connected?

[rtrags]

With the positive ground as you said i now get these voltages

Q1:
B= 0.11
E= 0.11
C= 0.09

Q2
B= 0.09
E= 0.10
C= 0.06

Im assuming i should not have any cables plugged into these jacks when i am measuring the voltages

[23]

Just make sure the orientation of the polarized caps are right and that the Trannies are oriented in the correct direction.

[rtrags]

I think I have tried every combination of of orientations between the caps and transistors. Is there a chance that they have become damage of the wrong orientation? When run my guitar thru it into my amp, I only get a dull crackling sound when a hit the strings quite hard. despite this all my solders on the jacks and pots are good.

[23]

Are you using a battery or a 9 volt wall adpter, usually when I would encounter this crackling sound when hitting the strings hard, the resistor that regulates the voltage was wrong (usually to big) or the battery was dead.
also if you using a 9 volt wall adapter it was the be center negative unless you have wired it the other way.
DID you install an LED? is it getting power?

[rtrags]

I have not installed an LED, where would i put that in my circuit? I am using a battery (8.6V). Which resistor regulates that voltage? With that battery and no guitar or amp plugged in, I am getting about 0.07V at every transistor terminal

[23]

led woul run off battery and left lower lg of 3pdt I think, been a while. Umm damn, someone chime in here..... Fuzz faces can be very fussy.

[LucifersTrip]

With the positive ground as you said i now get these voltages

Q1:
B= 0.11
E= 0.11
C= 0.09

Q2
B= 0.09
E= 0.10
C= 0.06

all voltages should be (-). remember, black of dmm on ground and red on lug you are measuring. regardless, these voltages are so far off, there's either a wiring error or bad/incorrect component(s) or you're measuring incorrectly.

did you breadboard first? what transistors are you using? gains?  leakages?  a closeup pic of your board?  

all of the above will help us help you.


edit: here're approx voltages you are shooting for

e   b    c
Q1:    0, -.1, -.6
Q2:  -.45, -.6, -4.5

[23]

THanks LUC......... coming off some meds mind is clouded

[LucifersTrip]

then yes I am using positive ground. I guess I am confused as to the terminology of ground. since in this schematic the battery's positive terminal is being used as ground (connected to the ring of the input jack), how does this differ where the other grounds are (Q1 emitter, middle lug of both pots....)? should they all be connected?

Q1 emitter, side lug of both pots (lug#1), + side of 20uF, grounds of both in/out jacks and + battery all to the same spot

but it is not good practice to have all leads going to one point. it is better practice to connect the points in a long line like a snake.

[rtrags]

I used one of the buses on the board to connect the 6 grounds on the schematic. Based on LucifersTrip's comment I also connected the + battery to the same bus and was able to get sound out of it when the ring of the input jack was connected to the - battery, but I'm pretty sure this shorted the circuit because the battery got hot. quick. I mis-spoke earlier when said that I grounded the middle pot lugs, (I had properly grounded the side lugs).

My transistors are two paired 3AX31C's from Small Bear. https://www.smallbearelec.com/HowTos/FuzzFaceFAQ/FFFAQ.htm contains the leakage information I believe.

When you say it is not good to have all leads going to a point, and it is better to have a "snake", is this to prevent a ground loop, which i rougly understand can produce hum? So the star ground is no good?

In the picures the top bus is -battery, the on just below it is the +battery. The bus in the middle I am using as the common ground.

My board: http://www.flickr.com/photos/84722452@N06/with/7756275274/#photo_7756275274 sorry I only used green wire.

Also I am not using a switch until I get the circuit itself down. Is the switch necessary?

Thanks for the help so far everyone.

[rtrags]

Got it. I had my collector and emitter leads flipped on both transistors. I was never confident about the pin outs for them. Thanks again for the help. Its way fuzzyier and over driven that I had expected, but now that I have a working circuit I can look up some mods. I think a tube amp would make it sound even better though, Im getting sick of my solid state line 6. Thanks again.

[LucifersTrip]

excellent...though, before mods, the next step is to re-check voltages and set the bias where you like it best

then mod til death.

[John Lyons]

Im assuming i should not have any cables plugged into these jacks when i am measuring the voltages
You need to have the input plug in the jack to get power to the circuit in order to test voltages.
The ring of the input jack (stereo 3 lug jack) makes a connection to the sleeve when you use a mono plug.
So if there is no plug in the jack you do not have a connection between battery ground (positive in this case)
and the grounding of the circuit.

[rtrags]

Good to know John thanks, and Lucifer what do you mean by biasing? how can I do this and what is it for?