FF Breadboard always sounds like it's 'dying'

[DJPsychic]

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

[PRR]

And there's no voltages in there?

[j_flanders]

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?

[antonis]

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..

[iainpunk]

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?

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)

[DJPsychic]

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?

[j_flanders]

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.

As far as voltages, I'm still quite a noob, so haven't really dived into that yet.

Do you have a (digital) multimeter?

[DJPsychic]

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

Do you have a (digital) multimeter?

what's that? (just kidding)

yes I do

[MaxPower]

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)?

[DJPsychic]

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.

[tonyharker]

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??

[DJPsychic]

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

[j_flanders]

Do you have a (digital) multimeter?

yes I do

Measure the voltages on collector, base and emitter on both transistors. Here's how:

[DJPsychic]

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.

[DJPsychic]

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.

[j_flanders]

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:

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.

[DJPsychic]

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:

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

[DJPsychic]

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

[willienillie]

Your Q2 is hooked up wrong somehow.  You should be seeing several volts at least on the collector.

A picture would be helpful.

[DJPsychic]

Your Q2 is hooked up wrong somehow.  You should be seeing several volts at least on the collector.

A picture would be helpful.