freestompboxes.org

In order to take up the issue of the topic
viewtopic.php?f=33&t=25331&p=245094&hil ... on#p245087,
I want to give you an information on the the pedal.

I grinded down the layer of joint sealing compound until a minimum has reached.
Afterwards I could remove the compound piece by piece.
I carefully removed the compound from the transistors and the IC, all but one became legible.
At least I removed all the componets and measured all values of each.
I made a PCB clone for and traced the circuit.
Measured transitor data: SprintLayout6-File:

Great work Manfred!

I did a layout for srtipboard...

Hi Mirosol

Great work too.

I compared the traced LED's characteristic curve with manufacturer specifications and found this suitable type:

Manfred, I must say thanks in actual writing for this comprehensive trace and schematic, complete with transistor data, LED curve data, and king bright part data sheet. On behalf of all us lurkers, Thanks!!!

Mirosol, thank you for those speedy ass vero layouts, I try to say thanks on the blog as much as possible, I appreciate all that you do for the community of solder junkies like myself.

dv8r601 wrote:Manfred, I must say thanks in actual writing for this comprehensive trace and schematic, complete with transistor data, LED curve data, and king bright part data sheet. On behalf of all us lurkers, Thanks!!!

Mirosol, thank you for those speedy ass vero layouts, I try to say thanks on the blog as much as possible, I appreciate all that you do for the community of solder junkies like myself.

Thank you very much for all the nice words.

Two connection lines in the schematic drawing were shifted, here the corrected schematic.

Manfred wrote: Two connection lines in the schematic drawing were shifted, here the corrected schematic.

What are the changes? I see two resistor values changed to 2k7 from 1k, but the topology seems the same - to me at least.

And one more question - are the MOSFET clippers correct? For the most, those are wired with gate and drain tied together.
+m

mirosol wrote:

Manfred wrote: Two connection lines in the schematic drawing were shifted, here the corrected schematic.

What are the changes? I see two resistor values changed to 2k7 from 1k, but the topology seems the same - to me at least.

And one more question - are the MOSFET clippers correct? For the most, those are wired with gate and drain tied together.
+m

Thanks a lot for take a close look at the schematic.
1 K is the right value.
Sorry, I probably forgot to save the CAD-drawing after exporting to the JPG-File.
Here the schematic drawing detail of the fault.
The another line fault was on a capacitor symbol. The MOSFET clippers are indeed correct, I am very surprised at.
I made a simulation with all four possible wirings of the MOSFET terminals.
The clipping curve has always the same shape.
I will made the test with the real clipping circuit varitions too.

The results of the simulation could be confirmed by measurements in the real circuit,
the clipped curves are regardless of the manner in which the gate terminal is connected to the other terminals.

Thats good to know. I always hook up the 2n7000 up the wrong way, glad to know that it sounds the same in this one no matter how I do it. I'm gonna try the zendrive trick with the germanium diode for true mosfet clipping today and see what that sounds like.
I am still shocked this sounds as damn good as it does. Its a pretty standard distortion with a few mods added in and it works wonderfully.

Yes wired in anti-parallel, like normal to ground clippers, it is just the body diode that does the clipping. If you want the internal zener clipping of the mosfet, you have to wire them like zeners.

Manfred, do you have a simulation with the 2n7000 removed? I wonder if they affect the sound at all.

roseblood11 wrote:Manfred, do you have a simulation with the 2n7000 removed? I wonder if they affect the sound at all.

Here the simulation shots:

@roseblood11: It didn't make a whole Hell of alotta difference in the sound without them. I'm wondering if there is some EE type reason for that or if I did something wrong. I used Miro's layout above as soon as he put it up.
And Manfred thanks for all this data. I really appreciate the time and effort. I know its a labour of love, but I would like to thank you none the less. Its people like you that make this such an amazing community. I've learned more here than the entire internet as far as electrical circuitry and the mechanical parts we use is concerned.