I bread boarded a FF that has worked before, and no matter what transistors I use, it has that dying battery sound.
If I lightly hit a string, the sound doesn't even come through the "fizz". I've tried multiple different types of both SI and GE transistors.
I even redid the entire breadboard ( http://diy.smallbearelec.com/HowTos/BreadboardSiFF/BreadboardSiFF.htm) and still the same result.
I'm goin nuts
And there's no voltages in there?
Wrong bias or dying battery. :)
Hard to tell if you do not supply us with the voltage readings of the collector, base and emitter of both transistors.
Pretty much all the resistors in that circuit affect the bias but a quick and dirty way to change it and get rid of the dying battery sound is to replace the usual 8k2 resistor on the collector of Q2 with a pot wired as a variable resistor.
For safety(?) measures it might be best to put a 1k series resistor in case you turn the pot to zero.
Question for the experts: is that 1k resistor in series really needed or will the 470r or 330r (and 1k on the emitter) be enough to limit the current?
(https://i.postimg.cc/j2KZbjWf/fuzzfacebias.png)
Quote from: j_flanders on April 09, 2020, 04:36:57 AM
Question for the experts: is that 1k resistor in series really needed or will the 470r or 330r (and 1k on the emitter) be enough to limit the current?
Definately I'm not any kind of "expert" but elementary maths & Ohm's law call for a current of 19mA (with 470R) when Q2 fully saturated..
Quote from: j_flanders on April 09, 2020, 04:36:57 AM
Wrong bias or dying battery. :)
Hard to tell if you do not supply us with the voltage readings of the collector, base and emitter of both transistors.
Pretty much all the resistors in that circuit affect the bias but a quick and dirty way to change it and get rid of the dying battery sound is to replace the usual 8k2 resistor on the collector of Q2 with a pot wired as a variable resistor.
For safety(?) measures it might be best to put a 1k series resistor in case you turn the pot to zero.
Question for the experts: is that 1k resistor in series really needed or will the 470r or 330r (and 1k on the emitter) be enough to limit the current?
(https://i.postimg.cc/j2KZbjWf/fuzzfacebias.png)
that 1K should be more than enough to limit the current. when looking at the emitter as an output, its basically a buffer when the pot is at 0 ohm, a bjt buffer works fine with only a 1K load resistor. (even at max current, it won't be more than 9mA)
Actually, I do have a 10k trimpot in place of the 8.k, along with a 1k between that and the .01uf output, which is actually a 6.8nf.
The only other alteration is a 10k pot at input, but i've removed, no effect.
Battery is new. Tried other batteries, and even other breadboards.
As far as voltages, I'm still quite a noob, so haven't really dived into that yet. I've had pretty good luck in the past with this circuit, messing with various values. I don't know why now it's doing this.
Also wouldn't trying multiple transistors, both GE and SI, and having the exact same result, rule out a bias issue?
Quote from: DJPsychic on April 09, 2020, 08:41:38 AM
Actually, I do have a 10k trimpot in place of the 8.k
Have you turned it?
Do you hear a difference between different settings?
Surely there has to be difference between min and max setting.
Quote from: DJPsychic on April 09, 2020, 08:41:38 AM
As far as voltages, I'm still quite a noob, so haven't really dived into that yet.
Do you have a (digital) multimeter?
Quote
Have you turned it?
Do you hear a difference between different settings?
Surely there has to be difference between min and max setting.
yes I have turned, nothing crazy. "min" signal much weaker, after that nothing earth shattering. I can hear subtle nuances
QuoteDo you have a (digital) multimeter?
what's that? (just kidding)
yes I do
Take voltage readings from the base, emitter, and collector of each transistor relative to ground.
Are you sure you have your power supply in the right polarity (positive ground for pnp)?
Quote from: MaxPower on April 09, 2020, 10:29:11 AM
Take voltage readings from the base, emitter, and collector of each transistor relative to ground.
Are you sure you have your power supply in the right polarity (positive ground for pnp)?
Yes it's a NPN build, I am using NPN transistors. I've got it wired like the small bear build I linked in OP.
You can't troubleshoot a circuit without test equipment. The minimum is a multimeter of some sort. Are you sure you have linked the power rails on the breadboard to the components??
Quote from: tonyharker on April 09, 2020, 02:56:14 PM
You can't troubleshoot a circuit without test equipment. The minimum is a multimeter of some sort. Are you sure you have linked the power rails on the breadboard to the components??
Yes
Quote from: DJPsychic on April 09, 2020, 09:25:53 AM
QuoteDo you have a (digital) multimeter?
yes I do
Measure the voltages on collector, base and emitter on both transistors. Here's how:
(https://i.postimg.cc/bvx5WdW2/dmm1.png)
(https://i.postimg.cc/qMP5j8qG/dmm2.png)
Real quick update - I changed all the pots to new ones and everything went back to normal. I was able to mess around for about 3 hours, switching components, transistors etc...my usual process, everything sounded great.
It wasn't until I switched the 33k with a 22k that things started getting weird again. I put the 33k back and was still getting the "dying" sound. I even tried changing transistors again, and same result. Maybe i just knocked something on the breadboard while changing, idk.
Quote
Measure the voltages on collector, base and emitter on both transistors. Here's how:
This will be my next step. Thank you for super helpful graphic. The smallbear instructions I have explain this as well.
I've never had a problems prototyping my pedals on breadboard, that's why it's an odd thing.
Quote from: DJPsychic on April 09, 2020, 06:29:23 PM
It wasn't until I switched the 33k with a 22k that things started getting weird again. I put the 33k back and was still getting the "dying" sound. I even tried changing transistors again, and same result. Maybe i just knocked something on the breadboard while changing, idk.
That resistor as well affects the bias of both transistors.
Some pedals don't use a trimpot instead of the 8k2 resistor on the collector of Q2 but use a 100k trimpot instead of that 33k. (My older Germanium Dunlop FF has a 10k resistor + 100k trimpot instead of the 33k for example.)
So far, I seem to prefer a trimpot on Q2 instead, even though that changes more than just the bias.
Until you start posting voltages we keep on shooting in the dark.
By the way, a simple circuit like this, I don't breadboard.
I simply solder it point to point but in a way that is easily adjustable.
I pretty much use the layout of the schematic.
I do use sockets for the transistors though, because a lot of soldering and desoldering might damage them (heat...)
If I would take an overhead photo of the circuit it woud look like the drawn schematics you find of a fuzz face.
In case that sounds too vague I mean my actual working/testing circuit looks like this:
(https://i.postimg.cc/fRYLGym9/p2p.png)
For one, it eliminates potential bad contacts in a breadboard.
It also gives (me) a better insight into what component is what, because they will in the same place as in the schematic.
Quote from: j_flanders on April 09, 2020, 07:11:24 PM
Quote from: DJPsychic on April 09, 2020, 06:29:23 PM
It wasn't until I switched the 33k with a 22k that things started getting weird again. I put the 33k back and was still getting the "dying" sound. I even tried changing transistors again, and same result. Maybe i just knocked something on the breadboard while changing, idk.
That resistor as well affects the bias of both transistors.
Some pedals don't use a trimpot instead of the 8k2 resistor on the collector of Q2 but use a 100k trimpot instead of that 33k. (My older Germanium Dunlop FF has a 10k resistor + 100k trimpot instead of the 33k for example.)
So far, I seem to prefer a trimpot on Q2 instead, even though that changes more than just the bias.
Until you start posting voltages we keep on shooting in the dark.
By the way, a simple circuit like this, I don't breadboard.
I simply solder it point to point but in a way that is easily adjustable.
I pretty much use the layout of the schematic.
I do use sockets for the transistors though, because a lot of soldering and desoldering might damage them (heat...)
If I would take an overhead photo of the circuit it woud look like the drawn schematics you find of a fuzz face.
In case that sounds too vague I mean my actual working/testing circuit looks like this:
(https://i.postimg.cc/fRYLGym9/p2p.png)
For one, it eliminates potential bad contacts in a breadboard.
It also gives (me) a better insight into what component is what, because they will in the same place as in the schematic.
Actually I do the same. I've built the circuit before and worked great. I tried replicating it and that's what when started having issues. That's when I decided to breadboard to work out the kinks. Ever since I've been running into the "dying" issue. Maybe it's just the city I live in lol
Ok here's what I came up with:
Battery - 9.17 V
2N229 GE
Q1 Q2
E 0 E .46
B .08 B .63
C .64 C .79
2N2222A SI
Q1 Q2
E 0 E .23
B .49 B 1.21
C 1.21 C .54
Your Q2 is hooked up wrong somehow. You should be seeing several volts at least on the collector.
A picture would be helpful.
Quote from: willienillie on April 10, 2020, 02:05:39 PM
Your Q2 is hooked up wrong somehow. You should be seeing several volts at least on the collector.
A picture would be helpful.
(https://i.postimg.cc/DJN4SGjV/49-BBC7-C2-C8-F1-4-E04-9-A6-E-96-BE3-D2-B65-D5.jpg) (https://postimg.cc/DJN4SGjV)
Your Q2 emitter is not connected to the 1K pot.
(https://i.postimg.cc/bGH7BJBs/49-BBC7-C2-C8-F1-4-E04-9-A6-E-96-BE3-D2-B65-D5.jpg) (https://postimg.cc/bGH7BJBs)
Quote from: willienillie on April 10, 2020, 03:08:32 PM
Your Q2 emitter is not connected to the 1K pot.
(https://i.postimg.cc/bGH7BJBs/49-BBC7-C2-C8-F1-4-E04-9-A6-E-96-BE3-D2-B65-D5.jpg) (https://postimg.cc/bGH7BJBs)
There is a jumper from the emitter of Q2 to CW of 1k Fuzz...
Okay I see, but then you need to ground the CCW end.
Quote from: willienillie on April 10, 2020, 03:24:51 PM
Okay I see, but then you need to ground the CCW end.
fixed ground, misplaced it when I tried to clean up for photo
Here's better shot of jumper
(https://i.postimg.cc/hJgX6Knf/7101-A3-D9-7-D2-B-43-E9-8-C76-1497-AF8-A5-C3-B.jpg) (https://postimg.cc/hJgX6Knf)
Okay. So I can't see it so well, but it looks like maybe you're using the two outside pins of the trimmer. In that case, it will act like a fixed resistor. You need to use the center (wiper) pin and one of the two outside pins. If that's how you do have it connected, then the issue is something else.
Quote from: willienillie on April 10, 2020, 03:38:48 PM
Okay. So I can't see it so well, but it looks like maybe you're using the two outside pins of the trimmer. In that case, it will act like a fixed resistor. You need to use the center (wiper) pin and one of the two outside pins. If that's how you do have it connected, then the issue is something else.
oh dang. I stole the configuration from GGG '69 fuzz build
(https://i.postimg.cc/wyNvxkN4/69trim.jpg) (https://postimg.cc/wyNvxkN4)
You can tie the unused outside pin to the wiper, makes no difference.
Quote from: willienillie on April 10, 2020, 04:40:46 PM
You can tie the unused outside pin to the wiper, makes no difference.
I put the unused one in circuit with other leg, basically putting them together. Surprisingly solved my issue for the time being?
I built a pedal only using 2 legs and works fine, didn't have same problem interesting...
I'm not 100% sure I'm understanding you fully. But in this application the trimmer (a pot really) is doing duty as a variable resistor. So you only need to use two of the pins, but one of those needs to be the middle/wiper pin. The leftover pin can be connected to the wiper if you like, but it makes no difference electronically. GGG connected that unused pin on the PCB you posted for mechanical strength, three soldered pins is 50% stronger than two. Sometimes when a full-size pot, connected with wires, is used as a variable resistor, people will solder the unused lug to the wiper so that part of the circuit doesn't go "open" if the wiper contact fails internally.
> only using 2 legs and works fine,
Which two?
Quote from: willienillie on April 10, 2020, 07:29:22 PM
I'm not 100% sure I'm understanding you fully. But in this application the trimmer (a pot really) is doing duty as a variable resistor. So you only need to use two of the pins, but one of those needs to be the middle/wiper pin. The leftover pin can be connected to the wiper if you like, but it makes no difference electronically. GGG connected that unused pin on the PCB you posted for mechanical strength, three soldered pins is 50% stronger than two. Sometimes when a full-size pot, connected with wires, is used as a variable resistor, people will solder the unused lug to the wiper so that part of the circuit doesn't go "open" if the wiper contact fails internally.
I was just surprised Connecting the other leg to the breadboard solved my issue.
As always, thank you all for the help. You're insights and taking the time to respond means a lot. I love building pedals, it's all I want to do.
Only issue I'm having is that little fart sound at the top of my signal. Kind of sounds liken a tiny busted speaker. I'm sure there's endless threads on the topic.. Tthis a biasing issue I'm assuming?
I biased few sets of transistors, still farty. Switched the 22uf to a 10uf and back, 22 seems a little cleaner, 10uf is a little tighter.
Finally tried a 15uf sprague I bought form Small Bear last year. Biased it, sounds amazing. Only problem is it's huge! I wish it was easier to find 15uf Lol
(https://i.postimg.cc/F73XXz29/98-E10-F3-C-6-B7-D-4945-BDD1-6063259309-F0.jpg) (https://postimg.cc/F73XXz29)
Quote from: DJPsychic on April 10, 2020, 09:42:37 PM
I biased few sets of transistors, still farty. Switched the 22uf to a 10uf and back, 22 seems a little cleaner, 10uf is a little tighter.
Finally tried a 15uf sprague I bought form Small Bear last year. Biased it, sounds amazing. Only problem is it's huge! lol
(https://i.postimg.cc/F73XXz29/98-E10-F3-C-6-B7-D-4945-BDD1-6063259309-F0.jpg) (https://postimg.cc/F73XXz29)