Feisty Little One - Thermal Detonator

turdadactyl · Post by **turdadactyl** » 30 Sep 2016, 20:42

I figured since I sponge knowledge from this place and don't have nearly as much to offer in the circuit analysis department, I'd throw some gut shots up of this seemingly rare fuzz. There is a piece of cardboard attached to the opposite side of the PCB, so I'll have to get around to pulling that off for more pics.

Both transistors are 2N3904.
The large cap is a 2.2 uF and the disc cap is .1nF.
The resistors from the pots are each 18 ohms.
The CLR on the LED is 1K.

turdadactyl · Post by **turdadactyl** » 01 Oct 2016, 01:01

Not the prettiest soldering ever.

turdadactyl · Post by **turdadactyl** » 01 Oct 2016, 12:34

I'm trying to get from this to a schematic but I'm no expert. If anybody happens to be inspired and gets it done first, the more the merrier.

deltafred · Post by **deltafred** » 01 Oct 2016, 15:12

Let's see - 2 silicon NPN transistors and 'FF' on the solder mask, it wouldn't be based on a silicon Fuzz Face by any chance would it?

turdadactyl · Post by **turdadactyl** » 01 Oct 2016, 15:23

deltafred wrote:Let's see - 2 silicon NPN transistors and 'FF' on the solder mask, it wouldn't be based on a silicon Fuzz Face by any chance would it?

They don't even try to pretend otherwise. From the website:

the thermal detonator is an oscillating fuzz pedal. the circuit itself is a fuzz face clone with silicon transistors. but we’ve added a couple features that give you many more options to create diverse sounds. this pedal is capable of effects similar to the zvex “fuzz factory” and the devi ever/effector 13 “truly beautiful disaster” (although the circuits are a bit different).

https://feistylittleone.wordpress.com/g ... detonator/

turdadactyl · Post by **turdadactyl** » 01 Oct 2016, 16:14

Well, here's my first attempt at a schematic from a pedal. Let's see if you guys think it's even remotely accurate.

FLO-ThermalDetonator102.pdf: Schematic First Attempt; (284.68 KiB) Downloaded 191 times

Manfred · Post by **Manfred** » 01 Oct 2016, 16:47

I started with the a PLC replica and I would like this to be looked at.
If no fault, then I will add the wiring.

Manfred · Post by **Manfred** » 01 Oct 2016, 22:26

Corrected Layout.
the pin assignments of the transistors were wrong.
A track was missing.

turdadactyl · Post by **turdadactyl** » 08 Oct 2016, 03:01

Posting this as an image/attachment to see if we can get any curious people to weigh in on accuracy.

Manfred · Post by **Manfred** » 08 Oct 2016, 07:26

I checked the schematic in compare to the layout and found some drawing errors.

The layout with added connection designations.

Manfred · Post by **Manfred** » 08 Oct 2016, 18:01

Hi turdadactyl,

what about the potentiometer values, do you know these?

turdadactyl · Post by **turdadactyl** » 08 Oct 2016, 20:08

Anybody know if the code printed on the backs of the pots are actual values?

Vol = 8G1
Bias = 0N1
Fuzz = 8A4
Sag = 0N1
OSC = ?

Zokk · Post by **Zokk** » 08 Oct 2016, 20:29

Hi,
you can see the value printed on the other side of the pots, but you'll have to remove the knobs to unscrew the pots.
Like this 250K Lin potentiometer:

Manfred · Post by **Manfred** » 08 Oct 2016, 21:46

turdadactyl wrote:Anybody know if the code printed on the backs of the pots are actual values?

Vol = 8G1
Bias = 0N1
Fuzz = 8A4
Sag = 0N1
OSC = ?

Hi,
could you please measure the values of the potentiometer with an ohmmeter in two positions,
at right stop and at the middle.
The ratio of both measured position values gives the curves typ.

turdadactyl · Post by **turdadactyl** » 08 Oct 2016, 22:54

Zokk I was just hoping against hope I could be lazy about it. I'll pull it apart or put a meter on them.

turdadactyl · Post by **turdadactyl** » 09 Oct 2016, 00:38

Pot values:

Vol = A500K
Bias = B10K
Fuzz = B1K
Sag = B10K
OSC = B500K

Manfred · Post by **Manfred** » 09 Oct 2016, 07:36

turdadactyl wrote:Pot values:

Vol = A500K
Bias = B10K
Fuzz = B1K
Sag = B10K
OSC = B500K

Thanks, execellent!

turdadactyl · Post by **turdadactyl** » 10 Oct 2016, 16:39

The more I look at this thing the more I think it's essentially a Fuzz Face version of a Parallel Universe

Manfred · Post by **Manfred** » 12 Oct 2016, 22:52

I completed the schematic according the images of the posts, with the request to check them.

turdadactyl · Post by **turdadactyl** » 14 Oct 2016, 15:08

For your listening pleasure:

Feisty Little One - Thermal Detonator [traced]